From 988656f475230e845fa3b553e97799b0829e9830 Mon Sep 17 00:00:00 2001
From: Cliff Click <cliffc@acm.org>
Date: Mon, 21 Apr 2025 14:18:23 -0700
Subject: Initial push

---
 .../java/com/seaofnodes/simple/BrainFuckTest.java  |  32 +
 .../java/com/seaofnodes/simple/Chapter01Test.java  |  95 +++
 .../java/com/seaofnodes/simple/Chapter02Test.java  |  61 ++
 .../java/com/seaofnodes/simple/Chapter03Test.java  |  73 ++
 .../java/com/seaofnodes/simple/Chapter04Test.java  | 131 ++++
 .../java/com/seaofnodes/simple/Chapter05Test.java  | 186 +++++
 .../java/com/seaofnodes/simple/Chapter06Test.java  | 305 ++++++++
 .../java/com/seaofnodes/simple/Chapter07Test.java  | 222 ++++++
 .../java/com/seaofnodes/simple/Chapter08Test.java  | 208 +++++
 .../java/com/seaofnodes/simple/Chapter09Test.java  | 296 +++++++
 .../java/com/seaofnodes/simple/Chapter10Test.java  | 397 ++++++++++
 .../java/com/seaofnodes/simple/Chapter11Test.java  | 551 +++++++++++++
 .../java/com/seaofnodes/simple/Chapter12Test.java  |  61 ++
 .../java/com/seaofnodes/simple/Chapter13Test.java  | 261 +++++++
 .../java/com/seaofnodes/simple/Chapter14Test.java  | 226 ++++++
 .../java/com/seaofnodes/simple/Chapter15Test.java  | 354 +++++++++
 .../java/com/seaofnodes/simple/Chapter16Test.java  | 261 +++++++
 .../java/com/seaofnodes/simple/Chapter17Test.java  | 555 +++++++++++++
 .../java/com/seaofnodes/simple/Chapter18Test.java  | 370 +++++++++
 .../java/com/seaofnodes/simple/Chapter19Test.java  | 331 ++++++++
 .../java/com/seaofnodes/simple/Chapter20Test.java  | 151 ++++
 .../java/com/seaofnodes/simple/Chapter21Test.java  | 259 ++++++
 .../test/java/com/seaofnodes/simple/Compile.java   |  65 ++
 .../src/test/java/com/seaofnodes/simple/Eval2.java | 450 +++++++++++
 .../test/java/com/seaofnodes/simple/EvalArm64.java | 360 +++++++++
 .../test/java/com/seaofnodes/simple/EvalRisc5.java | 352 +++++++++
 .../java/com/seaofnodes/simple/FuzzerWrap.java     |  43 +
 .../src/test/java/com/seaofnodes/simple/Main.java  |  18 +
 .../java/com/seaofnodes/simple/MergeSortTest.java  |  44 ++
 .../java/com/seaofnodes/simple/SchedulerTest.java  |  74 ++
 .../test/java/com/seaofnodes/simple/Simple.java    | 313 ++++++++
 .../test/java/com/seaofnodes/simple/TestArm64.java |  42 +
 .../src/test/java/com/seaofnodes/simple/TestC.java |  89 +++
 .../test/java/com/seaofnodes/simple/TestRisc5.java |  50 ++
 .../test/java/com/seaofnodes/simple/TypeTest.java  | 158 ++++
 .../com/seaofnodes/simple/evaluator/Evaluator.java | 383 +++++++++
 .../com/seaofnodes/simple/evaluator/Scheduler.java | 606 ++++++++++++++
 .../java/com/seaofnodes/simple/fuzzer/Fuzzer.java  | 174 +++++
 .../com/seaofnodes/simple/fuzzer/FuzzerUtils.java  | 111 +++
 .../java/com/seaofnodes/simple/fuzzer/Reducer.java | 176 +++++
 .../seaofnodes/simple/fuzzer/ScriptGenerator.java  | 869 +++++++++++++++++++++
 .../java/com/seaofnodes/simple/progs/antiDep1.smp  |  11 +
 .../java/com/seaofnodes/simple/progs/arg_count.c   |  10 +
 .../java/com/seaofnodes/simple/progs/arg_count.smp |   6 +
 .../java/com/seaofnodes/simple/progs/array1.smp    |   9 +
 .../java/com/seaofnodes/simple/progs/brain_fuck.c  |  18 +
 .../com/seaofnodes/simple/progs/brain_fuck.smp     |  46 ++
 .../test/java/com/seaofnodes/simple/progs/fib.c    |  16 +
 .../test/java/com/seaofnodes/simple/progs/fib.smp  |  11 +
 .../test/java/com/seaofnodes/simple/progs/jig.smp  |   2 +
 .../test/java/com/seaofnodes/simple/progs/loop2.c  |   7 +
 .../java/com/seaofnodes/simple/progs/loop2.smp     |  10 +
 .../java/com/seaofnodes/simple/progs/newtonFloat.c |  16 +
 .../com/seaofnodes/simple/progs/newtonFloat.smp    |  12 +
 .../seaofnodes/simple/progs/no_stack_arg_count.smp |   6 +
 .../test/java/com/seaofnodes/simple/progs/person.c |  34 +
 .../java/com/seaofnodes/simple/progs/person.smp    |   9 +
 .../test/java/com/seaofnodes/simple/progs/sieve.c  |  19 +
 .../java/com/seaofnodes/simple/progs/sieve.smp     |  31 +
 .../test/java/com/seaofnodes/simple/progs/sort.c   |  28 +
 .../test/java/com/seaofnodes/simple/progs/sort.smp |  38 +
 .../java/com/seaofnodes/simple/progs/stringHash.c  |  30 +
 .../com/seaofnodes/simple/progs/stringHash.smp     |  31 +
 63 files changed, 10163 insertions(+)
 create mode 100644 chapter22/src/test/java/com/seaofnodes/simple/BrainFuckTest.java
 create mode 100644 chapter22/src/test/java/com/seaofnodes/simple/Chapter01Test.java
 create mode 100644 chapter22/src/test/java/com/seaofnodes/simple/Chapter02Test.java
 create mode 100644 chapter22/src/test/java/com/seaofnodes/simple/Chapter03Test.java
 create mode 100644 chapter22/src/test/java/com/seaofnodes/simple/Chapter04Test.java
 create mode 100644 chapter22/src/test/java/com/seaofnodes/simple/Chapter05Test.java
 create mode 100644 chapter22/src/test/java/com/seaofnodes/simple/Chapter06Test.java
 create mode 100644 chapter22/src/test/java/com/seaofnodes/simple/Chapter07Test.java
 create mode 100644 chapter22/src/test/java/com/seaofnodes/simple/Chapter08Test.java
 create mode 100644 chapter22/src/test/java/com/seaofnodes/simple/Chapter09Test.java
 create mode 100644 chapter22/src/test/java/com/seaofnodes/simple/Chapter10Test.java
 create mode 100644 chapter22/src/test/java/com/seaofnodes/simple/Chapter11Test.java
 create mode 100644 chapter22/src/test/java/com/seaofnodes/simple/Chapter12Test.java
 create mode 100644 chapter22/src/test/java/com/seaofnodes/simple/Chapter13Test.java
 create mode 100644 chapter22/src/test/java/com/seaofnodes/simple/Chapter14Test.java
 create mode 100644 chapter22/src/test/java/com/seaofnodes/simple/Chapter15Test.java
 create mode 100644 chapter22/src/test/java/com/seaofnodes/simple/Chapter16Test.java
 create mode 100644 chapter22/src/test/java/com/seaofnodes/simple/Chapter17Test.java
 create mode 100644 chapter22/src/test/java/com/seaofnodes/simple/Chapter18Test.java
 create mode 100644 chapter22/src/test/java/com/seaofnodes/simple/Chapter19Test.java
 create mode 100644 chapter22/src/test/java/com/seaofnodes/simple/Chapter20Test.java
 create mode 100644 chapter22/src/test/java/com/seaofnodes/simple/Chapter21Test.java
 create mode 100644 chapter22/src/test/java/com/seaofnodes/simple/Compile.java
 create mode 100644 chapter22/src/test/java/com/seaofnodes/simple/Eval2.java
 create mode 100644 chapter22/src/test/java/com/seaofnodes/simple/EvalArm64.java
 create mode 100644 chapter22/src/test/java/com/seaofnodes/simple/EvalRisc5.java
 create mode 100644 chapter22/src/test/java/com/seaofnodes/simple/FuzzerWrap.java
 create mode 100644 chapter22/src/test/java/com/seaofnodes/simple/Main.java
 create mode 100644 chapter22/src/test/java/com/seaofnodes/simple/MergeSortTest.java
 create mode 100644 chapter22/src/test/java/com/seaofnodes/simple/SchedulerTest.java
 create mode 100644 chapter22/src/test/java/com/seaofnodes/simple/Simple.java
 create mode 100644 chapter22/src/test/java/com/seaofnodes/simple/TestArm64.java
 create mode 100644 chapter22/src/test/java/com/seaofnodes/simple/TestC.java
 create mode 100644 chapter22/src/test/java/com/seaofnodes/simple/TestRisc5.java
 create mode 100644 chapter22/src/test/java/com/seaofnodes/simple/TypeTest.java
 create mode 100644 chapter22/src/test/java/com/seaofnodes/simple/evaluator/Evaluator.java
 create mode 100644 chapter22/src/test/java/com/seaofnodes/simple/evaluator/Scheduler.java
 create mode 100644 chapter22/src/test/java/com/seaofnodes/simple/fuzzer/Fuzzer.java
 create mode 100644 chapter22/src/test/java/com/seaofnodes/simple/fuzzer/FuzzerUtils.java
 create mode 100644 chapter22/src/test/java/com/seaofnodes/simple/fuzzer/Reducer.java
 create mode 100644 chapter22/src/test/java/com/seaofnodes/simple/fuzzer/ScriptGenerator.java
 create mode 100644 chapter22/src/test/java/com/seaofnodes/simple/progs/antiDep1.smp
 create mode 100644 chapter22/src/test/java/com/seaofnodes/simple/progs/arg_count.c
 create mode 100644 chapter22/src/test/java/com/seaofnodes/simple/progs/arg_count.smp
 create mode 100644 chapter22/src/test/java/com/seaofnodes/simple/progs/array1.smp
 create mode 100644 chapter22/src/test/java/com/seaofnodes/simple/progs/brain_fuck.c
 create mode 100644 chapter22/src/test/java/com/seaofnodes/simple/progs/brain_fuck.smp
 create mode 100644 chapter22/src/test/java/com/seaofnodes/simple/progs/fib.c
 create mode 100644 chapter22/src/test/java/com/seaofnodes/simple/progs/fib.smp
 create mode 100644 chapter22/src/test/java/com/seaofnodes/simple/progs/jig.smp
 create mode 100644 chapter22/src/test/java/com/seaofnodes/simple/progs/loop2.c
 create mode 100644 chapter22/src/test/java/com/seaofnodes/simple/progs/loop2.smp
 create mode 100644 chapter22/src/test/java/com/seaofnodes/simple/progs/newtonFloat.c
 create mode 100644 chapter22/src/test/java/com/seaofnodes/simple/progs/newtonFloat.smp
 create mode 100644 chapter22/src/test/java/com/seaofnodes/simple/progs/no_stack_arg_count.smp
 create mode 100644 chapter22/src/test/java/com/seaofnodes/simple/progs/person.c
 create mode 100644 chapter22/src/test/java/com/seaofnodes/simple/progs/person.smp
 create mode 100644 chapter22/src/test/java/com/seaofnodes/simple/progs/sieve.c
 create mode 100644 chapter22/src/test/java/com/seaofnodes/simple/progs/sieve.smp
 create mode 100644 chapter22/src/test/java/com/seaofnodes/simple/progs/sort.c
 create mode 100644 chapter22/src/test/java/com/seaofnodes/simple/progs/sort.smp
 create mode 100644 chapter22/src/test/java/com/seaofnodes/simple/progs/stringHash.c
 create mode 100644 chapter22/src/test/java/com/seaofnodes/simple/progs/stringHash.smp

(limited to 'chapter22/src/test/java/com')

diff --git a/chapter22/src/test/java/com/seaofnodes/simple/BrainFuckTest.java b/chapter22/src/test/java/com/seaofnodes/simple/BrainFuckTest.java
new file mode 100644
index 00000000..391bba67
--- /dev/null
+++ b/chapter22/src/test/java/com/seaofnodes/simple/BrainFuckTest.java
@@ -0,0 +1,32 @@
+package com.seaofnodes.simple;
+
+import com.seaofnodes.simple.codegen.CodeGen;
+import com.seaofnodes.simple.node.cpus.riscv.riscv;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import org.junit.Test;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.fail;
+
+public class BrainFuckTest {
+
+    @Test public void testBrainFuck() throws IOException {
+        String brain_fuck = "Hello World!\n";
+        TestC.run("brain_fuck", brain_fuck, 40);
+
+        EvalRisc5 R5 = TestRisc5.build("brain_fuck", 0, 44, false);
+        int trap = R5.step(100000);
+        assertEquals(0,trap);
+        int ptr = (int)R5.regs[riscv.A0];
+        assertEquals(brain_fuck.length(),R5.ld4s(ptr));
+        for( int i=0; i<brain_fuck.length(); i++ )
+            assertEquals(brain_fuck.charAt(i), R5.ld1z(ptr+4+i));
+
+        // TODO: replace with ARM Eval
+        String src = Files.readString(Path.of("src/test/java/com/seaofnodes/simple/progs/brain_fuck.smp"));
+        Chapter21Test.testCPU(src,"arm", "SystemV",26,null);
+
+    }
+
+}
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/Chapter01Test.java b/chapter22/src/test/java/com/seaofnodes/simple/Chapter01Test.java
new file mode 100644
index 00000000..cddbdfcf
--- /dev/null
+++ b/chapter22/src/test/java/com/seaofnodes/simple/Chapter01Test.java
@@ -0,0 +1,95 @@
+package com.seaofnodes.simple;
+
+import com.seaofnodes.simple.codegen.CodeGen;
+import com.seaofnodes.simple.node.*;
+import com.seaofnodes.simple.type.TypeInteger;
+import org.junit.Test;
+
+import static org.junit.Assert.*;
+
+public class Chapter01Test {
+
+    @Test
+    public void testSimpleProgram() {
+        CodeGen code = new CodeGen("return 1;").parse();
+        Node expr = code.expr();
+        if( expr instanceof ConstantNode con ) {
+            assertEquals(code._start,con.in(0));
+            assertEquals(TypeInteger.constant(1), con._type);
+        } else {
+            fail();
+        }
+    }
+
+    @Test
+    public void testZero() {
+        CodeGen code = new CodeGen("return 0;");
+        code.parse();
+        for( Node use : code._start._outputs )
+            if( use instanceof ConstantNode con && con._type instanceof TypeInteger )
+                assertEquals(TypeInteger.constant(0),con._type);
+    }
+
+    @Test
+    public void testBad1() {
+        try {
+            new CodeGen("ret;").parse();
+            fail();
+        } catch( RuntimeException e ) {
+            assertEquals("Undefined name 'ret'",e.getMessage());
+        }
+    }
+
+    @Test
+    public void testBad2() {
+        try {
+            new CodeGen("return 0123;").parse();
+            fail();
+        } catch( RuntimeException e ) {
+            assertEquals("Syntax error: integer values cannot start with '0'",e.getMessage());
+        }
+    }
+
+    @Test
+    public void testNotBad3() {
+        // this test used to fail in chapter 1
+        assertEquals("return 12;", new CodeGen("return - -12;").parse()._stop.print());
+    }
+
+    @Test
+    public void testBad4() {
+        try {
+            new CodeGen("return 100").parse();
+            fail();
+        } catch( RuntimeException e ) {
+            assertEquals("Syntax error, expected ;: ",e.getMessage());
+        }
+    }
+
+    @Test
+    public void testNotBad5() {
+        // this test used to fail in chapter 1
+        assertEquals("return -100;", new CodeGen("return -100;").parse()._stop.print());
+    }
+
+    @Test
+    public void testBad6() {
+        try {
+            new CodeGen("return100;").parse();
+            fail();
+        } catch( RuntimeException e ) {
+            assertEquals("Undefined name 'return100'",e.getMessage());
+        }
+    }
+
+    @Test
+    public void testBad7() {
+        try {
+            new CodeGen("return 1;}").parse();
+            fail();
+        } catch( RuntimeException e ) {
+            assertEquals("Syntax error, unexpected: }",e.getMessage());
+        }
+    }
+
+}
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/Chapter02Test.java b/chapter22/src/test/java/com/seaofnodes/simple/Chapter02Test.java
new file mode 100644
index 00000000..631e1487
--- /dev/null
+++ b/chapter22/src/test/java/com/seaofnodes/simple/Chapter02Test.java
@@ -0,0 +1,61 @@
+package com.seaofnodes.simple;
+
+import com.seaofnodes.simple.codegen.CodeGen;
+import com.seaofnodes.simple.node.*;
+import com.seaofnodes.simple.type.TypeInteger;
+import org.junit.Test;
+
+import static org.junit.Assert.*;
+
+public class Chapter02Test {
+
+    @Test
+    public void testParseGrammar() {
+        CodeGen code = new CodeGen("return 1+2*3+-5;");
+        code.parse(); // No more disable peepholes
+        assertEquals("return 2;", code.print());
+    }
+
+    @Test
+    public void testAddPeephole() {
+        CodeGen code = new CodeGen("return 1+2;");
+        code.parse();
+        assertEquals("return 3;", code.print());
+    }
+
+    @Test
+    public void testSubPeephole() {
+        CodeGen code = new CodeGen("return 1-2;");
+        code.parse();
+        assertEquals("return -1;", code.print());
+    }
+
+    @Test
+    public void testMulPeephole() {
+        CodeGen code = new CodeGen("return 2*3;");
+        code.parse();
+        assertEquals("return 6;", code.print());
+    }
+
+    @Test
+    public void testDivPeephole() {
+        CodeGen code = new CodeGen("return 6/3;");
+        code.parse();
+        assertEquals("return 2;", code.print());
+    }
+
+    @Test
+    public void testMinusPeephole() {
+        CodeGen code = new CodeGen("return 6/-3;");
+        code.parse();
+        assertEquals("return -2;", code.print());
+    }
+
+    @Test
+    public void testExample() {
+        CodeGen code = new CodeGen("return 1+2*3+-5;");
+        code.parse();
+        assertEquals("return 2;", code.print());
+    }
+
+}
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/Chapter03Test.java b/chapter22/src/test/java/com/seaofnodes/simple/Chapter03Test.java
new file mode 100644
index 00000000..c4e4c91e
--- /dev/null
+++ b/chapter22/src/test/java/com/seaofnodes/simple/Chapter03Test.java
@@ -0,0 +1,73 @@
+package com.seaofnodes.simple;
+
+import com.seaofnodes.simple.codegen.CodeGen;
+import org.junit.Test;
+import static org.junit.Assert.*;
+
+public class Chapter03Test {
+
+    @Test
+    public void testVarDecl() {
+        CodeGen code = new CodeGen("int a=1; return a;");
+        code.parse(); assertEquals("return 1;", code.print());
+    }
+
+    @Test
+    public void testVarAdd() {
+        CodeGen code = new CodeGen("int a=1; int b=2; return a+b;");
+        code.parse();
+        assertEquals("return 3;", code.print());
+    }
+
+    @Test
+    public void testVarScope() {
+        CodeGen code = new CodeGen("int a=1; int b=2; int c=0; { int b=3; c=a+b; } return c;");
+        code.parse();
+        assertEquals("return 4;", code.print());
+    }
+
+    @Test
+    public void testVarScopeNoPeephole() {
+        CodeGen code = new CodeGen("int a=1; int b=2; int !c=0; { int b=3; c=a+b;  } return c; ");
+        code.parse();           // Peepholes always run now
+        assertEquals("return 4;", code.print());
+    }
+
+    @Test
+    public void testVarDist() {
+        CodeGen code = new CodeGen("int x0=1; int y0=2; int x1=3; int y1=4; return (x0-x1)*(x0-x1) + (y0-y1)*(y0-y1); ");
+        code.parse();
+        assertEquals("return 8;", code.print());
+    }
+
+    @Test
+    public void testSelfAssign() {
+        try {
+            new CodeGen("int a=a; return a;").parse();
+            fail();
+        } catch( RuntimeException e ) {
+            assertEquals("Undefined name 'a'",e.getMessage());
+        }
+    }
+
+    @Test
+    public void testRedeclareVar() {
+        try {
+            new CodeGen("int a=1; int b=2; int c=0; int b=3; c=a+b;").parse();
+            fail();
+        } catch( RuntimeException e ) {
+            assertEquals("Redefining name 'b'",e.getMessage());
+        }
+    }
+
+    @Test
+    public void testBad1() {
+        try {
+            new CodeGen("int a=1; int b=2; int !c=0; { int b=3; c=a+b;").parse();
+            fail();
+        } catch( RuntimeException e ) {
+            assertEquals("Syntax error, expected }: ",e.getMessage());
+        }
+    }
+
+}
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/Chapter04Test.java b/chapter22/src/test/java/com/seaofnodes/simple/Chapter04Test.java
new file mode 100644
index 00000000..c6199193
--- /dev/null
+++ b/chapter22/src/test/java/com/seaofnodes/simple/Chapter04Test.java
@@ -0,0 +1,131 @@
+package com.seaofnodes.simple;
+
+import com.seaofnodes.simple.codegen.CodeGen;
+import com.seaofnodes.simple.node.*;
+import com.seaofnodes.simple.type.TypeInteger;
+import org.junit.Test;
+import org.junit.Ignore;
+
+import static org.junit.Assert.*;
+
+public class Chapter04Test {
+
+    @Test
+    public void testPeephole() {
+        CodeGen code = new CodeGen("return 1+arg+2; ");
+        code.parse();
+        assertEquals("return (arg+3);", code.print());
+    }
+
+    @Test
+    public void testPeephole2() {
+        CodeGen code = new CodeGen("return (1+arg)+2;");
+        code.parse();
+        assertEquals("return (arg+3);", code.print());
+    }
+
+    @Test
+    public void testAdd0() {
+        CodeGen code = new CodeGen("return 0+arg;");
+        code.parse();
+        assertEquals("return arg;", code.print());
+    }
+
+    @Test
+    public void testAddAddMul() {
+        CodeGen code = new CodeGen("return arg+0+arg;");
+        code.parse();
+        assertEquals("return (arg<<1);", code.print());
+    }
+
+    @Test
+    public void testPeephole3() {
+        CodeGen code = new CodeGen("return 1+arg+2+arg+3; ");
+        code.parse();
+        assertEquals("return ((arg<<1)+6);", code.print());
+    }
+
+    @Test
+    public void testMul1() {
+        CodeGen code = new CodeGen("return 1*arg;");
+        code.parse();
+        assertEquals("return arg;", code.print());
+    }
+
+    @Test
+    public void testVarArg() {
+        CodeGen code = new CodeGen("return arg; ");
+        code.parse();
+        assertTrue(code.ctrl() instanceof  FunNode);
+        assertTrue(code.expr() instanceof ParmNode);
+    }
+
+    // Adding functions means `main` does not constant fold the incoming arg value
+    @Ignore @Test
+    public void testConstantArg() {
+        CodeGen code = new CodeGen("return arg; ", TypeInteger.constant(2), 123L).parse();
+        assertEquals("return 2;", code.expr().in(1).toString());
+    }
+
+    @Test
+    public void testCompEq() {
+        CodeGen code = new CodeGen("return 3==3; ");
+        code.parse();
+        assertEquals("return 1;", code.print());
+    }
+
+    @Test
+    public void testCompEq2() {
+        CodeGen code = new CodeGen("return 3==4; ");
+        code.parse();
+        assertEquals("return 0;", code.print());
+    }
+
+    @Test
+    public void testCompNEq() {
+        CodeGen code = new CodeGen("return 3!=3; ");
+        code.parse();
+        assertEquals("return 0;", code.print());
+    }
+
+    @Test
+    public void testCompNEq2() {
+        CodeGen code = new CodeGen("return 3!=4; ");
+        code.parse();
+        assertEquals("return 1;", code.print());
+    }
+
+    @Test
+    public void testBug1() {
+        CodeGen code = new CodeGen("int a=arg+1; int !b=a; b=1; return a+2; ");
+        code.parse();
+        assertEquals("return (arg+3);", code.print());
+    }
+
+    @Test
+    public void testBug2() {
+        CodeGen code = new CodeGen("int !a=arg+1; a=a; return a; ");
+        code.parse();
+        assertEquals("return (arg+1);", code.print());
+    }
+
+    @Test
+    public void testBug3() {
+        try { new CodeGen("inta=1; return a;").parse(); fail(); }
+        catch( RuntimeException e ) { assertEquals("Undefined name 'inta'",e.getMessage()); }
+    }
+
+    @Test
+    public void testBug4() {
+        CodeGen code = new CodeGen("return -arg;");
+        code.parse();
+        assertEquals("return (-arg);", code.print());
+    }
+
+    @Test
+    public void testBug5() {
+        CodeGen code = new CodeGen("return arg--2;");
+        code.parse();
+        assertEquals("return (arg--2);", code.print());
+    }
+}
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/Chapter05Test.java b/chapter22/src/test/java/com/seaofnodes/simple/Chapter05Test.java
new file mode 100644
index 00000000..d1dfd216
--- /dev/null
+++ b/chapter22/src/test/java/com/seaofnodes/simple/Chapter05Test.java
@@ -0,0 +1,186 @@
+package com.seaofnodes.simple;
+
+import com.seaofnodes.simple.codegen.CodeGen;
+import com.seaofnodes.simple.node.*;
+import org.junit.Test;
+
+import static org.junit.Assert.*;
+
+public class Chapter05Test {
+
+    @Test
+    public void testIfStmt() {
+        CodeGen code = new CodeGen(
+"""
+int a = 1;
+if (arg == 1)
+    a = arg+2;
+else {
+    a = arg-3;
+}
+return a;
+""");
+        code.parse().opto();
+        assertEquals("return Phi(Region,(arg+2),(arg-3));", code.print());
+    }
+
+    @Test
+    public void testTest() {
+        CodeGen code = new CodeGen(
+"""
+int c = 3;
+int b = 2;
+if (arg == 1) {
+    b = 3;
+    c = 4;
+}
+return c;
+""");
+        code.parse().opto();
+        assertEquals("return Phi(Region,4,3);", code.print());
+    }
+
+    @Test
+    public void testReturn2() {
+        CodeGen code = new CodeGen(
+"""
+if( arg==1 )
+    return 3;
+else
+    return 4;
+""");
+        code.parse();
+        assertEquals("return Phi(Region,3,4);", code.print());
+    }
+
+    @Test
+    public void testIfMergeB() {
+        CodeGen code = new CodeGen(
+"""
+int a=arg+1;
+int b=0;
+if( arg==1 )
+    b=a;
+else
+    b=a+1;
+return a+b;""");
+        code.parse().opto();
+        assertEquals("return ((arg<<1)+Phi(Region,2,3));", code.print());
+    }
+
+    @Test
+    public void testIfMerge2() {
+        CodeGen code = new CodeGen(
+"""
+int a=arg+1;
+int b=arg+2;
+if( arg==1 )
+    b=b+a;
+else
+    a=b+1;
+return a+b;""");
+        code.parse().opto();
+        assertEquals("return ((Phi(Region,(arg<<1),arg)+arg)+Phi(Region,4,5));", code.print());
+    }
+
+    @Test
+    public void testMerge3() {
+        CodeGen code = new CodeGen(
+"""
+int a=1;
+if( arg==1 )
+    if( arg==2 )
+        a=2;
+    else
+        a=3;
+else if( arg==3 )
+    a=4;
+else
+    a=5;
+return a;
+""");
+        code.parse().opto();
+        assertEquals("return Phi(Region,3,5,2,4);", code.print());
+    }
+
+    @Test
+    public void testMerge4() {
+        CodeGen code = new CodeGen(
+"""
+int a=0;
+int b=0;
+if( arg )
+    a=1;
+if( arg==0 )
+    b=2;
+return arg+a+b;
+""");
+        code.parse().opto();
+        assertEquals("return ((arg+Phi(Region,1,0))+Phi(Region,2,0));", code.print());
+    }
+
+    @Test
+    public void testMerge5() {
+        CodeGen code = new CodeGen(
+"""
+int a=arg==2;
+if( arg==1 )
+{
+    a=arg==3;
+}
+return a;
+""");
+        code.parse().opto();
+        assertEquals("return (arg==Phi(Region,3,2));", code.print());
+    }
+
+    @Test
+    public void testTrue() {
+      CodeGen code = new CodeGen("return true;").parse();
+      assertEquals("return 1;",code.print());
+    }
+
+    @Test
+    public void testHalfDef() {
+        try { new CodeGen("if( arg==1 ) int b=2; return b;").parse(); fail(); }
+        catch( RuntimeException e ) { assertEquals("Cannot define a 'b' on one arm of an if",e.getMessage()); }
+    }
+
+    @Test
+    public void testHalfDef2() {
+        try { new CodeGen("if( arg==1 ) { int b=2; } else { int b=3; } return b;").parse(); fail(); }
+        catch( RuntimeException e ) { assertEquals("Undefined name 'b'",e.getMessage()); }
+    }
+
+    @Test
+    public void testRegress1() {
+        try { new CodeGen("if(arg==2) int a=1; else int b=2; return a;").parse(); fail(); }
+        catch( RuntimeException e ) { assertEquals("Cannot define a 'a' on one arm of an if",e.getMessage()); }
+    }
+
+
+    @Test
+    public void testBadNum() {
+        try { new CodeGen("return 1-;").parse();  fail(); }
+        catch( RuntimeException e ) { assertEquals("Syntax error, expected an identifier or expression: ;",e.getMessage()); }
+    }
+
+    @Test
+    public void testKeyword1() {
+        try { new CodeGen("int true=0; return true;").parse(); fail(); }
+        catch( RuntimeException e ) { assertEquals("Expected an identifier, found 'true'",e.getMessage()); }
+    }
+
+    @Test
+    public void testKeyword2() {
+        try { new CodeGen("int else=arg; if(else) else=2; else else=1; return else;").parse(); fail(); }
+        catch( RuntimeException e ) { assertEquals("Expected an identifier, found 'else'",e.getMessage()); }
+    }
+
+    @Test
+    public void testKeyword3() {
+        try { new CodeGen("int a=1; ififif(arg);a=2;return a;").parse(); fail(); }
+        catch( RuntimeException e ) { assertEquals("Undefined name 'ififif'",e.getMessage()); }
+    }
+
+}
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/Chapter06Test.java b/chapter22/src/test/java/com/seaofnodes/simple/Chapter06Test.java
new file mode 100644
index 00000000..b6bc2bf3
--- /dev/null
+++ b/chapter22/src/test/java/com/seaofnodes/simple/Chapter06Test.java
@@ -0,0 +1,305 @@
+package com.seaofnodes.simple;
+
+import com.seaofnodes.simple.codegen.CodeGen;
+import com.seaofnodes.simple.node.*;
+import com.seaofnodes.simple.type.TypeInteger;
+import org.junit.Test;
+
+import static org.junit.Assert.*;
+
+public class Chapter06Test {
+
+    @Test
+    public void testPeepholeReturn() {
+        CodeGen code = new CodeGen("""
+if( true ) return 2;
+return 1;
+""");
+        code.parse().opto();
+        assertEquals("return 2;", code.print());
+        assertTrue(code.ctrl() instanceof FunNode);
+    }
+
+    @Test
+    public void testPeepholeRotate() {
+        CodeGen code = new CodeGen(
+"""
+int a = 1;
+if (arg)
+    a = 2;
+return (arg < a) < 3; // Because (arg < a) is a bool/uint1/[0-1], its always less than 3
+""");
+        code.parse().opto();
+        assertEquals("return 1;", code.print());
+    }
+
+    @Test
+    public void testPeepholeCFG() {
+        CodeGen code = new CodeGen(
+"""
+int a=1;
+if( true )
+  a=2;
+else
+  a=3;
+return a;
+""");
+        code.parse().opto();
+        assertEquals("return 2;", code.print());
+        assertTrue(code.ctrl() instanceof FunNode);
+    }
+
+    @Test
+    public void testIfIf() {
+        CodeGen code = new CodeGen(
+"""
+int a=1;
+if( arg!=1 )
+    a=2;
+else
+    a=3;
+int b=4;
+if( a==2 )
+    b=42;
+else
+    b=5;
+return b;
+""");
+        code.parse().opto();
+        assertEquals("return Phi(Region,42,5);", code.print());
+    }
+
+    @Test
+    public void testIfArgIf() {
+        CodeGen code = new CodeGen(
+"""
+int a=1;
+if( 1==1 )
+    a=2;
+else
+    a=3;
+int b=4;
+if( arg==2 )
+    b=a;
+else
+    b=5;
+return b;""");
+        code.parse().opto();
+        assertEquals("return Phi(Region,2,5);", code.print());
+    }
+
+    @Test
+    public void testMerge3With2() {
+        CodeGen code = new CodeGen(
+"""
+arg=2;
+int a=1;
+if( arg==1 )
+    if( arg==2 )
+        a=2;
+    else
+        a=3;
+else if( arg==3 )
+    a=4;
+else
+    a=5;
+return a;
+""", TypeInteger.constant(2), 123L).parse().opto();
+        assertEquals("return 5;", code.print());
+    }
+
+    @Test
+    public void testMerge3With1() {
+        CodeGen code = new CodeGen(
+"""
+arg=1;
+int a=1;
+if( arg==1 )
+    if( arg==2 )
+        a=2;
+    else
+        a=3;
+else if( arg==3 )
+    a=4;
+else
+    a=5;
+return a;
+""", TypeInteger.constant(1), 123L).parse().opto();
+        assertEquals("return 3;", code.print());
+    }
+
+    @Test
+    public void testMerge3Peephole() {
+        CodeGen code = new CodeGen(
+"""
+int a=1;
+if( arg==1 )
+    if( 1==2 )
+        a=2;
+    else
+        a=3;
+else if( arg==3 )
+    a=4;
+else
+    a=5;
+return a;
+""");
+        code.parse().opto();
+        assertEquals("return Phi(Region,3,5,4);", code.print());
+    }
+
+    @Test
+    public void testMerge3Peephole1() {
+        CodeGen code = new CodeGen(
+"""
+arg=1;
+int a=1;
+if( arg==1 )
+    if( 1==2 )
+        a=2;
+    else
+        a=3;
+else if( arg==3 )
+    a=4;
+else
+    a=5;
+return a;
+""", TypeInteger.constant(1), 123L);
+        code.parse().opto();
+        assertEquals("return 3;", code.print());
+    }
+
+    @Test
+    public void testMerge3Peephole3() {
+        CodeGen code = new CodeGen(
+"""
+arg=3;
+int a=1;
+if( arg==1 )
+    if( 1==2 )
+        a=2;
+    else
+        a=3;
+else if( arg==3 )
+    a=4;
+else
+    a=5;
+return a;
+""", TypeInteger.constant(3), 123L);
+        code.parse().opto();
+        assertEquals("return 4;", code.print());
+    }
+
+    @Test
+    public void testDemo1NonConst() {
+        CodeGen code = new CodeGen("""
+int a = 0;
+int b = 1;
+if( arg ) {
+    a = 2;
+    if( arg ) { b = 2; }
+    else b = 3;
+}
+return a+b;
+""");
+        code.parse().opto();
+        assertEquals("return Phi(Region,4,1);", code.print());
+    }
+
+
+    @Test
+    public void testDemo1True() {
+        CodeGen code = new CodeGen(
+"""
+arg=1;
+int a = 0;
+int b = 1;
+if( arg ) {
+    a = 2;
+    if( arg ) { b = 2; }
+    else b = 3;
+}
+return a+b;
+""", TypeInteger.constant(1), 123L);
+        code.parse().opto();
+        assertEquals("return 4;", code.print());
+    }
+
+    @Test
+    public void testDemo1False() {
+        CodeGen code = new CodeGen(
+"""
+arg=0;
+int a = 0;
+int b = 1;
+if( arg ) {
+    a = 2;
+    if( arg ) { b = 2; }
+    else b = 3;
+}
+return a+b;
+""", TypeInteger.constant(0), 123L);
+        code.parse().opto();
+        assertEquals("return 1;", code.print());
+    }
+
+    @Test
+    public void testDemo2NonConst() {
+        CodeGen code = new CodeGen("""
+int a = 0;
+int b = 1;
+int c = 0;
+if( arg ) {
+    a = 1;
+    if( arg==2 ) { c=2; } else { c=3; }
+    if( arg ) { b = 2; }
+    else b = 3;
+}
+return a+b+c;
+""");
+        code.parse().opto();
+        assertEquals("return Phi(Region,6,1,5);", code.print());
+    }
+
+
+    @Test
+    public void testDemo2True() {
+        CodeGen code = new CodeGen(
+"""
+arg=1;
+int a = 0;
+int b = 1;
+int c = 0;
+if( arg ) {
+    a = 1;
+    if( arg==2 ) { c=2; } else { c=3; }
+    if( arg ) { b = 2; }
+    else b = 3;
+}
+return a+b+c;
+""", TypeInteger.constant(1), 123L);
+        code.parse().opto();
+        assertEquals("return 6;", code.print());
+    }
+
+    @Test
+    public void testDemo2arg2() {
+        CodeGen code = new CodeGen(
+"""
+arg=2;
+int a = 0;
+int b = 1;
+int c = 0;
+if( arg ) {
+    a = 1;
+    if( arg==2 ) { c=2; } else { c=3; }
+    if( arg ) { b = 2; }
+    else b = 3;
+}
+return a+b+c;
+""", TypeInteger.constant(2), 123L);
+        code.parse().opto();
+        assertEquals("return 5;", code.print());
+    }
+
+}
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/Chapter07Test.java b/chapter22/src/test/java/com/seaofnodes/simple/Chapter07Test.java
new file mode 100644
index 00000000..88554323
--- /dev/null
+++ b/chapter22/src/test/java/com/seaofnodes/simple/Chapter07Test.java
@@ -0,0 +1,222 @@
+package com.seaofnodes.simple;
+
+import com.seaofnodes.simple.codegen.CodeGen;
+import com.seaofnodes.simple.node.*;
+import org.junit.Test;
+
+import static org.junit.Assert.*;
+
+public class Chapter07Test {
+
+    @Test
+    public void testExample() {
+        CodeGen code = new CodeGen(
+"""
+while(arg < 10) {
+    arg = arg + 1;
+}
+return arg;
+""");
+        code.parse();
+        assertEquals("return Phi(Loop,arg,(Phi_arg+1));", code.print());
+        assertTrue(code.ctrl() instanceof CProjNode);
+    }
+
+    @Test
+    public void testRegression() {
+        CodeGen code = new CodeGen(
+"""
+int a = 1;
+if(arg){}else{
+    while(a < 10) {
+        a = a + 1;
+    }
+}
+return a;
+""");
+        code.parse().opto();
+        assertEquals("return Phi(Region,1,Phi(Loop,1,(Phi_a+1)));", code.print());
+    }
+
+    @Test
+    public void testWhileNested() {
+        CodeGen code = new CodeGen(
+"""
+int sum = 0;
+int i = 0;
+while(i < arg) {
+    i = i + 1;
+    int j = 0;
+    while( j < arg ) {
+        sum = sum + j;
+        j = j + 1;
+    }
+}
+return sum;
+""");
+        code.parse().opto();
+        assertEquals("return Phi(Loop,0,Phi(Loop,Phi_sum,(Phi_sum+Phi(Loop,0,(Phi_j+1)))));", code.print());
+    }
+
+    @Test
+    public void testWhileScope() {
+        CodeGen code = new CodeGen(
+"""
+int a = 1;
+int b = 2;
+while(a < 10) {
+    if (a == 2) a = 3;
+    else b = 4;
+}
+return b;
+""");
+        code.parse();
+        assertEquals("return Phi(Loop,2,Phi(Region,Phi_b,4));", code.print());
+        assertTrue(code.ctrl() instanceof CProjNode);
+    }
+
+    @Test
+    public void testWhileNestedIfAndInc() {
+        CodeGen code = new CodeGen(
+"""
+int a = 1;
+int b = 2;
+while(a < 10) {
+    if (a == 2) a = 3;
+    else b = 4;
+    b = b + 1;
+    a = a + 1;
+}
+return b;
+""");
+        code.parse().opto();
+        assertEquals("return Phi(Loop,2,(Phi(Region,Phi_b,4)+1));", code.print());
+        assertTrue(code.ctrl() instanceof CProjNode);
+    }
+
+
+    @Test
+    public void testWhile() {
+        CodeGen code = new CodeGen(
+"""
+int a = 1;
+while(a < 10) {
+    a = a + 1;
+    a = a + 2;
+}
+return a;
+""");
+        code.parse();
+        assertEquals("return Phi(Loop,1,(Phi_a+3));", code.print());
+        assertTrue(code.ctrl() instanceof CProjNode);
+    }
+
+    @Test
+    public void testWhilePeep() {
+        CodeGen code = new CodeGen(
+"""
+int a = 1;
+while(a < 10) {
+    a = a + 1;
+    a = a + 2;
+}
+return a;
+""");
+        code.parse().opto();
+        assertEquals("return Phi(Loop,1,(Phi_a+3));", code.print());
+        assertTrue(code.ctrl() instanceof CProjNode);
+    }
+
+    @Test
+    public void testWhile2() {
+        CodeGen code = new CodeGen(
+"""
+int a = 1;
+while(arg) a = 2;
+return a;
+""");
+        code.parse();
+        assertEquals("return Phi(Loop,1,2);", code.print());
+        assertTrue(code.ctrl() instanceof CProjNode);
+    }
+
+    @Test
+    public void testWhile2Peep() {
+        CodeGen code = new CodeGen(
+"""
+int a = 1;
+while(arg) a = 2;
+return a;
+""");
+        code.parse().opto();
+        assertEquals("return Phi(Loop,1,2);", code.print());
+        assertTrue(code.ctrl() instanceof CProjNode);
+    }
+
+    @Test
+    public void testWhile3() {
+        CodeGen code = new CodeGen(
+"""
+int a = 1;
+while(a < 10) {
+    int b = a + 1;
+    a = b + 2;
+}
+return a;
+""");
+        code.parse();
+        assertEquals("return Phi(Loop,1,(Phi_a+3));", code.print());
+        assertTrue(code.ctrl() instanceof CProjNode);
+    }
+
+    @Test
+    public void testWhile3Peep() {
+        CodeGen code = new CodeGen(
+"""
+int a = 1;
+while(a < 10) {
+    int b = a + 1;
+    a = b + 2;
+}
+return a;
+""");
+        code.parse().opto();
+        assertEquals("return Phi(Loop,1,(Phi_a+3));", code.print());
+        assertTrue(code.ctrl() instanceof CProjNode);
+    }
+
+    @Test
+    public void testWhile4() {
+        CodeGen code = new CodeGen(
+"""
+int a = 1;
+int b = 2;
+while(a < 10) {
+    int b = a + 1;
+    a = b + 2;
+}
+return a;
+""");
+        code.parse();
+        assertEquals("return Phi(Loop,1,(Phi_a+3));", code.print());
+        assertTrue(code.ctrl() instanceof CProjNode);
+    }
+
+    @Test
+    public void testWhile4Peep() {
+        CodeGen code = new CodeGen(
+"""
+int a = 1;
+int b = 2;
+while(a < 10) {
+    int b = a + 1;
+    a = b + 2;
+}
+return a;
+""");
+        code.parse().opto();
+        assertEquals("return Phi(Loop,1,(Phi_a+3));", code.print());
+        assertTrue(code.ctrl() instanceof CProjNode);
+    }
+
+}
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/Chapter08Test.java b/chapter22/src/test/java/com/seaofnodes/simple/Chapter08Test.java
new file mode 100644
index 00000000..09669cc7
--- /dev/null
+++ b/chapter22/src/test/java/com/seaofnodes/simple/Chapter08Test.java
@@ -0,0 +1,208 @@
+package com.seaofnodes.simple;
+
+import com.seaofnodes.simple.codegen.CodeGen;
+import com.seaofnodes.simple.node.*;
+import org.junit.Assert;
+import org.junit.Test;
+
+import static org.junit.Assert.*;
+
+public class Chapter08Test {
+
+    @Test
+    public void testEx6() {
+        CodeGen code = new CodeGen(
+                """
+while(arg < 10) {
+    arg = arg + 1;
+    if (arg == 5)
+        break;
+    if (arg == 6)
+        break;
+}
+return arg;
+                """);
+        code.parse().opto();
+        assertEquals("return Phi(Region,(Phi(Loop,arg,Add)+1),Add,Phi_arg);", code.print());
+        assertTrue(code.ctrl() instanceof RegionNode);
+        Assert.assertEquals( "5", Eval2.eval(code, 1));
+        Assert.assertEquals("10", Eval2.eval(code, 6));
+    }
+
+
+    @Test
+    public void testEx5() {
+        CodeGen code = new CodeGen(
+                """
+int a = 1;
+while(arg < 10) {
+    arg = arg + 1;
+    if (arg == 5)
+        continue;
+    if (arg == 7)
+        continue;
+    a = a + 1;
+}
+return a;
+                """);
+        code.parse().opto();
+        assertEquals("return Phi(Loop,1,Phi(Region,Phi_a,(Phi_a+1),Phi_a));", code.print());
+        assertTrue(code.ctrl() instanceof CProjNode);
+    }
+
+
+    @Test
+    public void testEx4() {
+        CodeGen code = new CodeGen(
+                """
+while(arg < 10) {
+    arg = arg + 1;
+    if (arg == 5)
+        continue;
+    if (arg == 6)
+        break;
+}
+return arg;
+                """);
+        code.parse().opto();
+        assertEquals("return Phi(Region,Phi(Loop,arg,(Phi_arg+1)),Add);", code.print());
+        assertTrue(code.ctrl() instanceof RegionNode);
+    }
+
+    @Test
+    public void testEx3() {
+        CodeGen code = new CodeGen(
+                """
+while(arg < 10) {
+    arg = arg + 1;
+    if (arg == 6)
+        break;
+}
+return arg;
+                """);
+        code.parse().opto();
+        assertEquals("return Phi(Region,Phi(Loop,arg,(Phi_arg+1)),Add);", code.print());
+        assertTrue(code.ctrl() instanceof RegionNode);
+    }
+
+
+    @Test
+    public void testEx2() {
+        CodeGen code = new CodeGen(
+                """
+while(arg < 10) {
+    arg = arg + 1;
+    if (arg == 5)
+        continue;
+    if (arg == 6)
+        continue;
+}
+return arg;
+                """);
+        code.parse().opto();
+        assertEquals("return Phi(Loop,arg,(Phi_arg+1));", code.print());
+        assertTrue(code.ctrl() instanceof CProjNode);
+    }
+
+
+    @Test
+    public void testEx1() {
+        CodeGen code = new CodeGen(
+                """
+while(arg < 10) {
+    arg = arg + 1;
+    if (arg == 5)
+        continue;
+}
+return arg;
+                """);
+        code.parse().opto();
+        assertEquals("return Phi(Loop,arg,(Phi_arg+1));", code.print());
+        assertTrue(code.ctrl() instanceof CProjNode);
+    }
+
+    @Test
+    public void testRegress1() {
+        CodeGen code = new CodeGen(
+                """
+while( arg < 10 ) {
+    int a = arg+2;
+    if( a > 4 )
+        break;
+}
+return arg;
+                """);
+        code.parse().opto();
+        assertEquals("return arg;", code.print());
+    }
+
+    @Test
+    public void testRegress2() {
+        CodeGen code = new CodeGen("if(1) return 0;  else while(arg>- -arg) arg=arg+1; return 0;");
+        code.parse().opto();
+        assertEquals("return 0;", code.print());
+    }
+
+    @Test
+    public void testBreakOutsideLoop() {
+        try {
+            new CodeGen("""
+if(arg <= 10) {
+    break;
+    arg = arg + 1;
+}
+return arg;
+""").parse();
+            fail();
+        } catch( RuntimeException e ) {
+            assertEquals("No active loop for a break or continue",e.getMessage());
+        }
+    }
+
+    @Test
+    public void testRegress3() {
+        CodeGen code = new CodeGen("""
+while(arg < 10) {
+    break;
+}
+return arg;
+""");
+        code.parse().opto();
+        assertEquals("return arg;", code.print());
+    }
+
+    @Test
+    public void testRegress4() {
+        CodeGen code = new CodeGen("""
+int a = 1;
+while(arg < 10) {
+    a = a + 1;
+    if (arg > 2) {
+        int a = 17;
+        break;
+    }
+}
+return a;
+""");
+        code.parse().opto();
+        assertEquals("return Phi(Region,Phi(Loop,1,(Phi_a+1)),Add);", code.print());
+        assertTrue(code.ctrl() instanceof RegionNode);
+    }
+
+    @Test
+    public void testRegress5() {
+        CodeGen code = new CodeGen("""
+int a = 1;
+while(1) {
+    a = a + 1;
+    if (a<10) continue;
+    break;
+}
+return a;
+""");
+        code.parse().opto();
+        assertEquals("return (Phi(Loop,1,Add)+1);", code.print());
+        assertTrue(code.ctrl() instanceof CProjNode prj && prj._idx==1 );
+    }
+
+}
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/Chapter09Test.java b/chapter22/src/test/java/com/seaofnodes/simple/Chapter09Test.java
new file mode 100644
index 00000000..401f346f
--- /dev/null
+++ b/chapter22/src/test/java/com/seaofnodes/simple/Chapter09Test.java
@@ -0,0 +1,296 @@
+package com.seaofnodes.simple;
+
+import com.seaofnodes.simple.codegen.CodeGen;
+import com.seaofnodes.simple.type.Type;
+import com.seaofnodes.simple.type.TypeInteger;
+import org.junit.Assert;
+import org.junit.Test;
+import org.junit.Ignore;
+
+import static org.junit.Assert.*;
+
+public class Chapter09Test {
+
+    @Test
+    @Ignore
+    public void testJig() {
+        CodeGen code = new CodeGen("""
+int v0=0;
+arg=0;
+while(v0) {
+        while(1) if(arg*arg*0==0) {}
+                while(0) {}
+    arg=1;
+}
+return 0;
+                """);
+        code.parse().opto();
+    }
+
+    @Test
+    public void testGVN1() {
+        CodeGen code = new CodeGen(
+                """
+int x = arg + arg;
+if(arg < 10) {
+    return arg + arg;
+}
+else {
+    x = x + 1;
+}
+return x;
+                """);
+        code.parse().opto();
+        assertEquals("return Phi(Region,(arg<<1),(Shl+1));", code.print());
+        Assert.assertEquals( "2", Eval2.eval(code,  1));
+        Assert.assertEquals("23", Eval2.eval(code, 11));
+    }
+
+    @Test
+    public void testGVN2() {
+        CodeGen code = new CodeGen("return arg*arg-arg*arg;");
+        code.parse().opto();
+        assertEquals("return 0;", code.print());
+        Assert.assertEquals("0", Eval2.eval(code,  1, 1));
+    }
+
+    @Test
+    public void testWorklist1() {
+        CodeGen code = new CodeGen("""
+int step = 1;
+while (arg < 10) {
+    arg = arg + step + 1;
+}
+return arg;
+""");
+        code.parse().opto();
+        assertEquals("return Phi(Loop,arg,(Phi_arg+2));", code.print());
+        Assert.assertEquals("11", Eval2.eval(code,  1));
+    }
+
+    @Test
+    public void testWorklist2() {
+        CodeGen code = new CodeGen(
+                """
+int cond = 0;
+int one = 1;
+while (arg < 10) {
+    if (cond) one = 2;
+    arg = arg + one*3 + 1;
+}
+return arg;
+                """);
+        code.parse().opto();
+        assertEquals("return Phi(Loop,arg,(Phi_arg+4));", code.print());
+        Assert.assertEquals("13", Eval2.eval(code,  1));
+    }
+
+    @Test
+    public void testWorklist3() {
+        CodeGen code = new CodeGen(
+                """
+int v1 = 0;
+int v2 = 0;
+int v3 = 0;
+int v4 = 0;
+int v5 = 0;
+int v6 = 0;
+int v7 = 0;
+int v8 = 0;
+while (arg) {
+    if (v1) v2 = 1;
+    if (v2) v3 = 1;
+    if (v3) v4 = 1;
+    if (v4) v5 = 1;
+    if (v5) v6 = 1;
+    if (v6) v7 = 1;
+    if (v7) v8 = 1;
+    arg = arg + v8 + 1;
+}
+return arg;
+                """);
+        code.parse().opto();
+        assertEquals("return 0;", code.print());
+    }
+
+    @Test
+    public void testRegionPeepBug() {
+        CodeGen code = new CodeGen(
+                """
+int v0=0;
+int v1=0;
+while(v1+arg) {
+    arg=0;
+    int v2=v0;
+    while(arg+1) {}
+    v0=1;
+    v1=v2;
+}
+                """);
+        code.parse().opto();
+        assertEquals("return 0;", code.print());
+    }
+
+    @Test
+    public void testWhile0() {
+        CodeGen code = new CodeGen("while(0) continue; if(0) arg=0;");
+        code.parse().opto();
+        assertEquals("return 0;", code.print());
+    }
+
+    @Test
+    public void testWhile1() {
+        CodeGen code = new CodeGen("""
+if(0) while(0) {
+    int arg=arg;
+    while(0) {}
+}
+""");
+        code.parse().opto();
+        assertEquals("return 0;", code.print());
+    }
+
+
+    @Test
+    public void testPrecedence() {
+        CodeGen code = new CodeGen("return 3-1+2;");
+        code.parse().opto();
+        assertEquals("return 4;", code.print());
+    }
+
+    @Test
+    public void testSwap2() {
+        CodeGen code = new CodeGen("return 1+(1+1);");
+        code.parse().opto();
+        assertEquals("return 3;", code.print());
+    }
+
+
+    @Test
+    public void testFuzz0() {
+        CodeGen code = new CodeGen("""
+int one = 1;
+int a = 0;
+int zero = 0;
+while(arg) {
+    a = -(one + a + 2);
+    arg = arg + 1;
+    one = one + zero;
+}
+return a;
+""");
+        code.parse().opto();
+        assertEquals("return Phi(Loop,0,(-(Phi_a+3)));", code.print());
+    }
+
+    @Test
+    public void testFuzz1() {
+        CodeGen code = new CodeGen("""
+while(1) {}
+while(arg) break;
+while(arg) arg=0;
+arg=0;
+int v0=0!=0<-0;
+return -0+0+0;
+""");
+        code.parse().opto();
+        assertEquals("return Top;", code.print());
+    }
+
+
+    @Test
+    public void testFuzz2() {
+        CodeGen code = new CodeGen("return 0+-0;");
+        code.parse().opto();
+        assertEquals("return 0;", code.print());
+    }
+
+    @Test
+    public void testFuzz3() {
+        CodeGen code = new CodeGen("int v0=0; while(0==69) while(v0) return 0;");
+        code.parse().opto();
+        assertEquals("return 0;", code.print());
+    }
+
+    @Test
+    public void testFuzz4() {
+        CodeGen code = new CodeGen("""
+while(1) {
+    arg=0<=0;
+    if(1<0) while(arg==-0) arg=arg-arg;
+}
+""");
+        code.parse().opto();
+        assertEquals("return Top;", code.print());
+    }
+
+    @Test
+    public void testFuzz5() {
+        CodeGen code = new CodeGen("""
+{
+    int v0=0;
+    while(1)
+            int v1=0--0;
+    while(v0)
+        break;
+    while(-v0) {
+        while(0+0+v0) continue;
+        break;
+    }
+    if(-0!=-0+0+v0) while(0+0+0+0)
+                break;
+}
+return 0!=0;
+""");
+        code.parse().opto();
+        assertEquals("return Top;", code.print());
+    }
+
+    @Test
+    public void testFuzz6() {
+        CodeGen code = new CodeGen(
+"""
+int v0=0;
+while(0==1) while(v0)
+        v0=1+v0;
+""");
+        code.parse().opto();
+        assertEquals("return 0;", code.print());
+    }
+
+    @Test
+    public void testFuzz7() {
+        CodeGen code = new CodeGen("""
+while(1) {}
+int v0=0;
+while(v0)
+    {}
+int v1=0;
+while(1)
+        v1=1;
+return v1+v0;
+                                   """);
+        code.parse().opto();
+        assertEquals("return Top;", code.print());
+    }
+
+    @Test
+    public void testFuzz8() {
+        CodeGen code = new CodeGen("while(arg) arg = arg - 1;  return arg;");
+        code.parse().opto();
+        assertEquals("return 0;", code.print());
+    }
+
+    @Test
+    public void testMeet() {
+        Type t1 = Type.TOP;
+        Type t2 = TypeInteger.TOP;
+        Assert.assertEquals(TypeInteger.TOP, t1.meet(t2));
+        Assert.assertEquals(TypeInteger.TOP, t2.meet(t1));
+        t1 = Type.BOTTOM;
+        t2 = TypeInteger.BOT;
+        Assert.assertEquals(Type.BOTTOM, t1.meet(t2));
+        Assert.assertEquals(Type.BOTTOM, t2.meet(t1));
+    }
+
+}
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/Chapter10Test.java b/chapter22/src/test/java/com/seaofnodes/simple/Chapter10Test.java
new file mode 100644
index 00000000..1253e4a6
--- /dev/null
+++ b/chapter22/src/test/java/com/seaofnodes/simple/Chapter10Test.java
@@ -0,0 +1,397 @@
+package com.seaofnodes.simple;
+
+import com.seaofnodes.simple.codegen.CodeGen;
+import org.junit.Test;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.fail;
+
+public class Chapter10Test {
+
+    @Test
+    public void testFuzzer() {
+        CodeGen code = new CodeGen(
+"""
+int a = arg/3;
+int b = arg*5;
+int x = arg*7;
+int y = arg/11;
+int p; int g; int h;
+if( (arg/13)==0 ) {
+    p = x + y;
+    g = x;
+    h = y;
+} else {
+    p = a + b;
+    g = a;
+    h = b;
+}
+int r = g+h;
+return p-r;
+""");
+        code.parse().opto();
+        assertEquals("return 0;", code.print());
+    }
+
+    @Test
+    public void testStruct() {
+        CodeGen code = new CodeGen("""
+struct Bar {
+    int a;
+    int b;
+};
+struct Foo {
+    int x;
+};
+Foo? foo = null;
+Bar !bar = new Bar;
+bar.a = 1;
+bar.a = 2;
+return bar.a;
+""");
+        code.parse().opto();
+        assertEquals("return 2;", code.print());
+    }
+
+    @Test
+    public void testExample() {
+        CodeGen code = new CodeGen("""
+struct Vector2D { int x; int y; };
+Vector2D !v = new Vector2D;
+v.x = 1;
+if (arg)
+    v.y = 2;
+else
+    v.y = 3;
+return v;
+""");
+        code.parse().opto();
+        assertEquals("return Vector2D;", code.print());
+    }
+
+    @Test
+    public void testBug() {
+        CodeGen code = new CodeGen("""
+struct s0 {
+    int v0;
+};
+s0? v1=null;
+int v3=v1.zAicm;
+""");
+        try { code.parse();  fail(); }
+        catch( Exception e ) {  assertEquals("Accessing unknown field 'zAicm' from 'null'",e.getMessage());  }
+    }
+
+    @Test
+    public void testBug2() {
+        CodeGen code = new CodeGen("""
+struct s0 { int v0; };
+arg=0+new s0.0;
+""");
+        try { code.parse(); fail(); }
+        catch( Exception e ) { assertEquals("Expected an identifier, found 'null'",e.getMessage()); }
+    }
+
+    @Test
+    public void testLoop() {
+        CodeGen code = new CodeGen("""
+struct Bar { int a; };
+Bar !bar = new Bar;
+while (arg) {
+    bar.a = bar.a + 2;
+    arg = arg + 1;
+}
+return bar.a;
+""");
+        code.parse().opto();
+        assertEquals("return Phi(Loop,0,(Phi_a+2));", code.print());
+    }
+
+    @Test
+    public void testIf() {
+        CodeGen code = new CodeGen("""
+struct Bar { int a; };
+Bar !bar = new Bar;
+if (arg) bar = null;
+bar.a = 1;
+return bar.a;
+""");
+        try { code.parse().opto(); fail(); }
+        catch( Exception e ) { assertEquals("Type null is not of declared type *Bar",e.getMessage()); }
+    }
+
+    @Test
+    public void testIf2() {
+        CodeGen code = new CodeGen("""
+struct Bar { int a; };
+Bar? !bar = null;
+if (arg) bar = new Bar;
+bar.a = 1;
+return bar.a;
+""");
+        try { code.parse().opto().typeCheck(); fail(); }
+        catch( Exception e ) { assertEquals("Might be null accessing 'a'",e.getMessage()); }
+    }
+
+    @Test
+    public void testIf3() {
+        CodeGen code = new CodeGen("""
+struct Bar { int a; };
+Bar bar = null;
+if (arg) bar = null;
+bar.a = 1;
+return bar.a;
+""");
+        try { code.parse(); fail(); }
+        catch( Exception e ) { assertEquals("Type null is not of declared type *Bar", e.getMessage()); }
+    }
+
+    @Test
+    public void testIfOrNull() {
+        CodeGen code = new CodeGen("""
+struct Bar { int a; };
+Bar? !bar = new Bar;
+if (arg) bar = null;
+if( bar ) bar.a = 1;
+return bar;
+""");
+        code.parse().opto();
+        assertEquals("return Phi(Region,null,Bar);", code.print());
+    }
+
+    @Test
+    public void testIfOrNull2() {
+        CodeGen code = new CodeGen(
+"""
+struct Bar { int a; };
+Bar? !bar = new Bar;
+if (arg) bar = null;
+int rez = 3;
+if( !bar ) rez=4;
+else bar.a = 1;
+return rez;
+""");
+        code.parse().opto();
+        assertEquals("return Phi(Region,4,3);", code.print());
+    }
+
+    @Test
+    public void testWhileWithNullInside() {
+        CodeGen code = new CodeGen("""
+struct s0 {int v0;};
+s0? !v0 = new s0;
+int ret = 0;
+while(arg) {
+    ret = v0.v0;
+    v0 = null;
+    arg = arg - 1;
+}
+return ret;
+""");
+        try { code.parse().opto().typeCheck(); fail(); }
+        catch( Exception e ) {
+            assertEquals("Might be null accessing 'v0'", e.getMessage()); }
+    }
+
+    @Test
+    public void testRedeclareStruct() {
+        CodeGen code = new CodeGen("""
+struct s0 {
+    int v0;
+};
+s0? v1=new s0;
+s0? v1;
+v1=new s0;
+""");
+        try { code.parse(); fail(); }
+        catch( Exception e ) { assertEquals("Redefining name 'v1'", e.getMessage()); }
+    }
+
+    @Test
+    public void testIter() {
+        // Build and use an iterator
+        CodeGen code = new CodeGen(
+"""
+struct Iter {
+    int x;
+    int len;
+};
+Iter !i = new Iter;
+i.len = arg;
+int sum=0;
+while( i.x < i.len ) {
+    sum = sum + i.x;
+    i.x = i.x + 1;
+}
+return sum;
+""");
+        code.parse().opto();
+        assertEquals("return Phi(Loop,0,(Phi(Loop,0,(Phi_x+1))+Phi_sum));", code.print());
+    }
+
+
+    @Test
+    public void test1() {
+        CodeGen code = new CodeGen("""
+struct s0 {int v0;};
+s0 !ret = new s0;
+while(arg) {
+    s0 !v0 = new s0;
+    v0.v0 = arg;
+    arg = arg-1;
+    if (arg==5) ret=v0;
+
+}
+return ret;
+""");
+        code.parse().opto();
+        assertEquals("return Phi(Loop,s0,Phi(Region,s0,Phi_ret));", code.print());
+    }
+
+    @Test
+    public void test2() {
+        CodeGen code = new CodeGen("""
+struct s0 {int v0;};
+s0 !ret = new s0;
+s0 !v0 = new s0;
+while(arg) {
+    v0.v0 = arg;
+    arg = arg-1;
+    if (arg==5) ret=v0;
+
+}
+return ret;
+""");
+        code.parse().opto();
+        assertEquals("return Phi(Loop,s0,Phi(Region,s0,Phi_ret));", code.print());
+    }
+
+
+    @Test
+    public void test3() {
+        CodeGen code = new CodeGen("""
+struct s0 {int v0;};
+s0 !ret = new s0;
+while(arg < 10) {
+    s0 !v0 = new s0;
+    if (arg == 5) ret=v0;
+    arg = arg + 1;
+}
+return ret;
+""");
+        code.parse().opto();
+        assertEquals("return Phi(Loop,s0,Phi(Region,s0,Phi_ret));", code.print());
+    }
+
+    @Test
+    public void testBug3() {
+        CodeGen code = new CodeGen("""
+struct s0 { int f0; };
+return new s0;
+int v0=null.f0;
+""");
+        try { code.parse();  fail(); }
+        catch( Exception e ) {  assertEquals("Accessing unknown field 'f0' from 'null'",e.getMessage());  }
+    }
+
+    @Test
+    public void testBug4() {
+        CodeGen code = new CodeGen("""
+if(0) {
+    while(0) if(arg) continue;
+    int v0=0;
+    while(1) {
+        int v2=-arg;
+        v0=v2;
+    }
+}
+   """);
+        code.parse().opto();
+        assertEquals("return 0;", code.print());
+    }
+
+    @Test
+    public void testBug5() {
+        CodeGen code = new CodeGen("""
+struct s0 {
+    int f0;
+};
+if(0) return 0;
+else return new s0;
+if(new s0.f0) return 0;
+    """);
+        code.parse().opto();
+        assertEquals("return s0;", code.print());
+    }
+
+    @Test
+    public void testBug6MissedWorklist() {
+        CodeGen code = new CodeGen("""
+while(0) {}
+int v4=0;
+while(0<arg) {
+    v4=v4+1;
+    while(1) v4=-v4;
+    while(0) arg=-1;
+}
+return 0;
+    """);
+        code.parse().opto();
+    }
+
+    @Test
+    public void testBug7() {
+        CodeGen code = new CodeGen("""
+struct s0 {  int f0; };
+s0 v0 = new s0;
+while(v0.f0) {}
+s0 v1 = v0;
+return v1;
+    """);
+        code.parse().opto();
+        assertEquals("return (const)s0;", code.print());
+    }
+
+
+    @Test
+    public void testBug8() {
+        CodeGen code = new CodeGen("""
+int v2=0;
+while(0)
+while(0) {}
+{
+    {
+        {
+            int v36=0;
+            {
+                while(0) {
+                    {
+                        while(-v2) {
+                            {
+                                while(v36) {
+                                                while(v2) return 0;
+                                                break;
+                                }                            }
+                            if(-v2) break;
+                        }
+                    }
+                }
+            }
+        }    }
+}
+""");
+        code.parse().opto();
+        assertEquals("return 0;", code.print());
+    }
+
+    @Test
+    public void testBug9() {
+        CodeGen code = new CodeGen("""
+int v0=arg==0;
+while(v0) continue;
+return 0;
+""");
+        code.parse().opto();
+        assertEquals("return 0;", code.print());
+    }
+
+}
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/Chapter11Test.java b/chapter22/src/test/java/com/seaofnodes/simple/Chapter11Test.java
new file mode 100644
index 00000000..f6539ac4
--- /dev/null
+++ b/chapter22/src/test/java/com/seaofnodes/simple/Chapter11Test.java
@@ -0,0 +1,551 @@
+package com.seaofnodes.simple;
+
+import com.seaofnodes.simple.codegen.CodeGen;
+import org.junit.Test;
+import static org.junit.Assert.assertEquals;
+
+public class Chapter11Test {
+
+    // A placeholder test used to rapidly rotate through fuzzer produced issues
+    @Test
+    public void testFuzzer() {
+        CodeGen code = new CodeGen(
+"""
+while(---- -arg) {
+    while(-arg) {
+        while(-----arg*---0) {
+                int N=--false==false<--arg;
+                while(N<-4==N) {
+                    N=N+N;
+                }
+            }
+        {
+            int kzEl_r7EYz=3*----0!=-arg<(37*--97!=0/arg==arg)<=-(--arg!=0);
+            while(kzEl_r7EYz<---1) {
+                kzEl_r7EYz=kzEl_r7EYz+kzEl_r7EYz*arg>=24;
+                if(7) continue;
+                kzEl_r7EYz=false;
+                if(-kzEl_r7EYz+arg<-3) continue;
+                else {
+                    while(kzEl_r7EYz) continue;
+                    arg=----3;
+                    kzEl_r7EYz=-(-----arg*1>-kzEl_r7EYz);
+                    int v2uF_4ba=9;
+                }
+            }
+        }
+        int pjcp7rv=arg;
+        {
+            int m2ya3=--arg-pjcp7rv;
+            while(m2ya3<-----pjcp7rv>=pjcp7rv+--pjcp7rv!=---pjcp7rv!=-arg<---(-m2ya3)>m2ya3<=-----true>14!=--m2ya3) {
+                m2ya3=m2ya3+-(--0<=false<pjcp7rv/arg<=-true);
+                while((--m2ya3)<--arg<-----arg*false!=arg<pjcp7rv*arg) {
+                    pjcp7rv=-3+-arg;
+                    break;
+                }
+                while(-3) {
+                    while(67+0-61) m2ya3=m2ya3;
+                    if(----pjcp7rv==---(---arg)) pjcp7rv=0!=-23;
+                    else pjcp7rv=----89;
+                    while(m2ya3!=m2ya3<pjcp7rv) m2ya3=1;
+                    while(--arg<=pjcp7rv) pjcp7rv=-32<=-m2ya3+62;
+                }
+                break;
+            }
+        }
+        {
+            int arg=-1<-9!=(-arg>=-pjcp7rv>=arg<=arg);
+            while(arg<-arg) {
+                arg=arg+--arg;
+                {
+                    while((--93)--pjcp7rv*-pjcp7rv+arg) arg=0-(6>=(--(---41/(0))!=--pjcp7rv)>=---2*33);
+                    pjcp7rv=11;
+                    int c=pjcp7rv;
+                    if(--107) break;
+                    else break;
+                }
+            }
+        }
+        pjcp7rv=pjcp7rv;
+        int aR0Wkua=-pjcp7rv==pjcp7rv;
+        {
+            if(-0!=-0) while(-true) break;
+            else {
+                while(aR0Wkua) pjcp7rv=-0/pjcp7rv;
+                pjcp7rv=pjcp7rv;
+            }
+        }
+    }
+    if(-arg) {
+        {
+            int Isdlt0fr91=0!=arg;
+            while(Isdlt0fr91<-Isdlt0fr91==-Isdlt0fr91+true) {
+                Isdlt0fr91=Isdlt0fr91+-1!=true;
+                if(-arg) if(--arg<=Isdlt0fr91) Isdlt0fr91=-Isdlt0fr91;
+                int i=---arg<---arg!=--40;
+                {
+                    int jVX43Ln4Dm=-(6)==-Isdlt0fr91/----0;
+                    while(jVX43Ln4Dm<--(3-3)) {
+                        jVX43Ln4Dm=jVX43Ln4Dm+-0<25;
+                        i=24<--(jVX43Ln4Dm);
+                    }
+                }
+                i=(arg!=----false>=7);
+                int Te=5>-arg;
+                break;
+            }
+        }
+        arg=arg!=--true/arg;
+        {
+            int UX=arg;
+            while(UX<-3*arg) {
+                UX=UX+arg/-1;
+                arg=-3--(-UX- -47<arg==--arg==arg)/arg- -UX>=-arg;
+                if(---12) while(-UX) break;
+                break;
+            }
+        }
+        continue;
+    }
+    if(arg) arg=--0;
+    else if(1) continue;
+    int DtTlhjYq=19==arg;
+    {
+        arg=--DtTlhjYq<=(DtTlhjYq/---DtTlhjYq<=-DtTlhjYq);
+        if(---arg) continue;
+        else {
+                int Zsl=40;
+                while(Zsl<--Zsl--false>((Zsl))==Zsl!=--DtTlhjYq-DtTlhjYq-DtTlhjYq) {
+                    Zsl=Zsl+arg;
+                }
+            }
+        if((arg)) if(-DtTlhjYq) {
+            }
+            else while(((2)==3*arg/DtTlhjYq)<=0==---arg) return false;
+        else {
+                int lwbF=arg>=0;
+                while(lwbF<57) {
+                    lwbF=lwbF+--(-arg+lwbF)>=-2>=arg!=arg;
+                    arg=----0+0;
+                    while(49) break;
+                    if(true) DtTlhjYq=-----arg;
+                    DtTlhjYq=0!=-----(0);
+                }
+            }
+        arg=---arg!=DtTlhjYq/--0;
+        DtTlhjYq=-DtTlhjYq/(--arg<arg);
+        if(32) {
+                int q=-DtTlhjYq;
+                while(q<arg*(0*q)/0) {
+                    q=q+DtTlhjYq;
+                    DtTlhjYq=arg;
+                }
+            }
+        else if(--arg) if(15) break;
+                else arg=0==arg<=-55>DtTlhjYq;
+            else {
+            }
+        DtTlhjYq=-0;
+        {
+            while((0)<-arg) DtTlhjYq=-DtTlhjYq;
+        }
+        if(30/--(arg)>=0) DtTlhjYq=-0>=arg;
+        else {
+            int Y2wcIQJ=--DtTlhjYq*---11;
+            if(arg==arg) {
+                Y2wcIQJ=-----Y2wcIQJ;
+                Y2wcIQJ=Y2wcIQJ<7;
+                if(DtTlhjYq) arg=arg;
+                else break;
+                while(-arg!=-31==(false<=-15>=-DtTlhjYq+--6*-----Y2wcIQJ<=---arg!=-Y2wcIQJ<=---0<-arg*--Y2wcIQJ)) DtTlhjYq=arg!=3;
+            }
+            continue;
+        }
+        arg=DtTlhjYq;
+        arg=--3/(---arg)>=80>=-DtTlhjYq<=DtTlhjYq;
+        arg=51+---(-true)!=arg!=----1==-DtTlhjYq;
+        if(11<=arg) if((arg)+79<32+(-arg)) continue;
+            else if(true==DtTlhjYq) break;
+        break;
+    }
+}
+if(arg!=62==arg) {
+    while(---arg) {
+        {
+            int bhmDacPM=arg/arg;
+            while(bhmDacPM<arg) {
+                bhmDacPM=bhmDacPM+80*((-bhmDacPM)/---bhmDacPM>1)<bhmDacPM-2!=7;
+                arg=-0;
+                arg=bhmDacPM>=-arg+-arg;
+                break;
+            }
+        }
+        int arg=true;
+        arg=arg<=arg;
+        {
+            int KlC=30;
+            while(KlC<-2) {
+                KlC=KlC+-1!=25<=-KlC>KlC>----0;
+                int Ij=arg>=-arg<=---10;
+                {
+                    int LAbgurVa2R=-arg!=Ij;
+                    while(LAbgurVa2R<-true) {
+                        LAbgurVa2R=LAbgurVa2R+Ij;
+                        KlC=-LAbgurVa2R;
+                        Ij=42*(-Ij>true);
+                        while(Ij) arg=KlC;
+                        KlC=-----7>-(--KlC<--7)==-LAbgurVa2R;
+                    }
+                }
+                int a=Ij<=-KlC;
+                if(Ij) {
+                    int r1W=a!=-false;
+                }
+                else {
+                    arg=56>=Ij;
+                    while(54) break;
+                    arg=8>=-(a<--Ij)/a>=-a-KlC;
+                }
+                int Yt_T=KlC;
+                arg=KlC;
+            }
+        }
+        if(----false/--arg/12+-----0) if(-9+-arg) while(arg!=(arg)) arg=--1>=-71-arg!=---(--arg*11+102)/--arg;
+            else if(----arg) continue;
+        if(-arg-arg) {
+            arg=-(-arg)*--(-3)<(-7==-arg----arg);
+            {
+                int arg=arg;
+                while(arg<-0>arg==-arg-(-arg>1+11)) {
+                    arg=arg+6-arg!=--0>---30>=---arg<=arg/(3)+---arg;
+                }
+            }
+            arg=-arg+arg;
+            arg=--47+-arg<1>arg*(-arg==-arg- -0>3);
+            arg=(----arg)!=arg+--59;
+            arg=- -4+arg==-(arg)-arg;
+        }
+        else {
+            while(--true-----true*-25+-18>arg>=-----(-arg)---13) {
+                arg=-0+--true<false;
+                continue;
+            }
+            arg=true<=arg;
+            break;
+        }
+        arg=arg*22<--(0+-arg);
+        {
+            continue;
+        }
+    }
+    arg=1*---((3<=true)==---2);
+    arg=7+-(-1);
+    return arg+--true;
+}
+else {
+    int o3ypEsewxM=-(---arg);
+    int vzXB=(-(---11<=--o3ypEsewxM>=--0))<=-0/-arg;
+    int L=-arg;
+    int B4mHcrf=---vzXB;
+    int oZWGdzZl=-o3ypEsewxM;
+    int K6tQqa1=11;
+    while(0!=--L) {
+            int sdZfTM=vzXB*true+K6tQqa1;
+            while(sdZfTM<false) {
+                sdZfTM=sdZfTM+arg;
+                sdZfTM=oZWGdzZl;
+                K6tQqa1=-K6tQqa1;
+                arg=---K6tQqa1;
+                while((3+-K6tQqa1)<oZWGdzZl) {
+                    if(-----(-1)) sdZfTM=-false;
+                    {}
+                }
+                K6tQqa1=vzXB!=-(B4mHcrf+-7>false);
+                sdZfTM=vzXB;
+            }
+        }
+    L=false;
+    while(31) B4mHcrf=arg;
+    oZWGdzZl=-0<--oZWGdzZl<=--2;
+    if(K6tQqa1>=20<=46) {
+        if(-1+-L) if(oZWGdzZl) {
+                int wmhv=-----0;
+            }
+        int arg=0;
+        o3ypEsewxM=---(oZWGdzZl);
+        return -oZWGdzZl/0;
+    }
+    else if(arg) {
+            int yKk5=B4mHcrf>=4>K6tQqa1<-B4mHcrf/o3ypEsewxM;
+            return -K6tQqa1;
+        }
+        else {
+            if(---0) {
+                {}
+                {}
+            }
+            return o3ypEsewxM;
+        }
+}
+""");
+        code.parse().opto().typeCheck().GCM();
+        assertEquals("return 9;", code.print());
+    }
+
+
+    @Test
+    public void testPrimes() {
+        CodeGen code = new CodeGen(
+"""
+if( arg < 2 ) return 0;
+int primeCount = 1;
+int prime = 3;
+while( prime <= arg ) {
+    int isPrime = 1;
+    // Check for even case, so the next loop need only check odds
+    if( (prime/2)*2 == prime )
+        continue;
+    // Check odds up to sqrt of prime
+    int j = 3;
+    while( j*j <= prime ) {
+        if( (prime/j)*j == prime ) {
+            isPrime = 0;
+            break;
+        }
+        j = j + 2;
+    }
+    if( isPrime )
+        primeCount = primeCount + 1;
+    prime = prime + 2;
+}
+return primeCount;
+""");
+        code.parse().opto();
+        assertEquals("return Phi(Region,0,Phi(Loop,1,Phi(Region,Phi_primeCount,Phi_primeCount,(Phi_primeCount+1))));", code.print());
+        assertEquals("0", Eval2.eval(code,  1)); // No primes 1 or below
+        assertEquals("1", Eval2.eval(code,  2)); // 2
+        assertEquals("2", Eval2.eval(code,  3)); // 2, 3
+        assertEquals("2", Eval2.eval(code,  4)); // 2, 3
+        assertEquals("3", Eval2.eval(code,  5)); // 2, 3, 5
+        assertEquals("4", Eval2.eval(code, 10)); // 2, 3, 5, 7
+    }
+
+    @Test
+    public void testAntiDeps1() {
+        CodeGen code = new CodeGen(
+"""
+struct S { int f; };
+S !v=new S;
+v.f = 2;
+int i=new S.f;
+i=v.f;
+if (arg) v.f=1;
+return i;
+""");
+        code.parse().opto();
+        assertEquals("return 2;", code.print());
+        assertEquals("2", Eval2.eval(code, 0));
+        assertEquals("2", Eval2.eval(code, 1));
+    }
+
+    @Test
+    public void testAntiDeps2() {
+        CodeGen code = new CodeGen(
+"""
+struct S { int f; };
+S !v = new S;
+v.f = arg;
+S !t = new S;
+int i = 0;
+if (arg) {
+    if (arg+1) v = t;
+    i = v.f;
+} else {
+    v.f = 2;
+}
+return i;
+""");
+        code.parse().opto();
+        assertEquals("return Phi(Region,.f,0);", code.print());
+    }
+
+    @Test
+    public void testAntiDeps3() {
+        CodeGen code = new CodeGen(
+"""
+struct S { int f; };
+S !v0 = new S;
+S? v1;
+if (arg) v1 = new S;
+if (v1) {
+    v0.f = v1.f;
+} else {
+    v0.f = 2;
+}
+return v0;
+""");
+        code.parse().opto();
+        assertEquals("return S;", code.print());
+    }
+
+
+    @Test
+    public void testAntiDeps4() {
+        CodeGen code = new CodeGen(
+"""
+struct S { int f; };
+S !v = new S;
+v.f = arg;
+S t = new S;
+int i = v.f;
+if (arg+1) arg= 0;
+while (arg) v.f = 2;
+return i;
+""");
+        code.parse().opto();
+        assertEquals("return arg;", code.print());
+    }
+
+    @Test
+    public void testAntiDeps5() {
+        CodeGen code = new CodeGen(
+"""
+struct S { int f; };
+S !v = new S;
+while(1) {
+    while(arg+1) { arg=arg-1; }
+    if (arg) break;
+    v.f = 2;
+}
+return v;
+""");
+        code.parse().opto();
+        assertEquals("return S;", code.print());
+    }
+
+    @Test
+    public void testAntiDeps6() {
+        CodeGen code = new CodeGen(
+"""
+struct s { int v; };
+s !ptr=new s;
+while( -arg )
+  ptr = new s;
+while(1)
+  arg = arg+ptr.v;
+""");
+        code.parse().opto();
+        assertEquals("return Top;", code.print());
+    }
+
+    @Test
+    public void testAntiDeps7() {
+        CodeGen code = new CodeGen(
+"""
+struct S { int f; };
+S !v = new S;
+S t = new S;
+int i = v.f;
+while (arg) {
+    v.f = arg;
+    arg = arg-1;
+}
+return i;
+""");
+        code.parse().opto();
+        assertEquals("return 0;", code.print());
+    }
+
+    @Test
+    public void testAntiDeps8() {
+        CodeGen code = new CodeGen(
+"""
+struct S { int f; };
+S !v = new S;
+S t = new S;
+while(arg) {
+    arg=arg-1;
+    int f = v.f;
+    v.f = 2;
+    if (arg) arg = f;
+    else v.f = 3;
+}
+return arg;
+""");
+        code.parse().opto();
+        assertEquals("return 0;", code.print());
+    }
+
+    @Test
+    public void testAntiDeps9() {
+        CodeGen code = new CodeGen(
+"""
+struct S { int f; };
+S !v = new S;
+S t = new S;
+if (arg) {
+    v.f=2;
+    int i=t.f;
+    v.f=i;
+}
+return v;
+""");
+        code.parse().opto();
+        assertEquals("return S;", code.print());
+    }
+
+    @Test
+    public void testExample2() {
+        CodeGen code = new CodeGen(
+"""
+struct S { int f; };
+S !v = new S;
+int i = arg;
+while (arg > 0) {
+    int j = i/3;
+    if (arg == 5)
+        v.f = j;
+    arg = arg - 1;
+}
+return v;
+                """);
+        code.parse().opto();
+        //assertEquals("return new S;", code.print());
+    }
+
+    @Test
+    public void testScheduleUse() {
+        CodeGen code = new CodeGen(
+"""
+int v0=0;
+while(0>=0) {
+    u1 v1=0;
+    v1=v0;
+    if(v1*0)
+        v0=-v1;
+}
+return 0;
+""");
+        code.parse().opto();
+        assertEquals("return Top;", code.print());
+    }
+
+    @Test
+    public void testLoopCarriedDep() {
+        CodeGen code = new CodeGen(
+"""
+u32 v0=0;
+{
+    int v1=0;
+    while(v1) {
+        v1=1>>>v0!=0;
+        v0=v1/0;
+    }
+    return v1;
+}
+""");
+        code.parse().opto();
+        assertEquals("return 0;", code.print());
+    }
+
+}
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/Chapter12Test.java b/chapter22/src/test/java/com/seaofnodes/simple/Chapter12Test.java
new file mode 100644
index 00000000..8069ddaa
--- /dev/null
+++ b/chapter22/src/test/java/com/seaofnodes/simple/Chapter12Test.java
@@ -0,0 +1,61 @@
+package com.seaofnodes.simple;
+
+import com.seaofnodes.simple.codegen.CodeGen;
+import com.seaofnodes.simple.node.StopNode;
+import org.junit.Test;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.fail;
+
+public class Chapter12Test {
+    @Test
+    public void testJig() {
+        CodeGen code = new CodeGen(
+"""
+return 3.14;
+""");
+        code.parse().opto();
+        assertEquals("return 3.14;", code.print());
+        assertEquals("3.14", Eval2.eval(code,  0));
+    }
+
+    @Test
+    public void testFloat() {
+        CodeGen code = new CodeGen(
+"""
+return 3.14;
+""");
+        code.parse().opto();
+        assertEquals("return 3.14;", code.print());
+        assertEquals("3.14", Eval2.eval(code,  0));
+    }
+
+    @Test
+    public void testSquareRoot() {
+        CodeGen code = new CodeGen(
+"""
+flt guess = arg;
+while( 1 ) {
+    flt next = (arg/guess + guess)/2;
+    if( next == guess ) break;
+    guess = next;
+}
+return guess;
+""");
+        code.parse().opto();
+        assertEquals("return Phi(Loop,(flt)arg,(((ToFloat/Phi_guess)+Phi_guess)*0.5f));", code.print());
+        assertEquals("3.0", Eval2.eval(code,  9));
+        assertEquals("1.414213562373095", Eval2.eval(code,  2));
+    }
+
+    @Test
+    public void testFPOps() {
+        CodeGen code = new CodeGen(
+"""
+flt x = arg;
+return x+1==x;
+""");
+        code.parse().opto();
+        assertEquals("return ((flt)arg==(ToFloat+1.0f));", code.print());
+        assertEquals("0", Eval2.eval(code, 1));
+    }
+}
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/Chapter13Test.java b/chapter22/src/test/java/com/seaofnodes/simple/Chapter13Test.java
new file mode 100644
index 00000000..6bf45a22
--- /dev/null
+++ b/chapter22/src/test/java/com/seaofnodes/simple/Chapter13Test.java
@@ -0,0 +1,261 @@
+package com.seaofnodes.simple;
+
+import com.seaofnodes.simple.codegen.CodeGen;
+import org.junit.Test;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.fail;
+
+public class Chapter13Test {
+    @Test
+    public void testJig() {
+        CodeGen code = new CodeGen(
+"""
+return 3.14;
+""");
+        code.parse().opto();
+        assertEquals("return 3.14;", code.print());
+        assertEquals("3.14", Eval2.eval(code,  0));
+    }
+
+    @Test
+    public void testLinkedList0() {
+        CodeGen code = new CodeGen(
+"""
+struct LLI { LLI? next; int i; };
+LLI? !head = null;
+while( arg ) {
+    LLI !x = new LLI;
+    x.next = head;
+    x.i = arg;
+    head = x;
+    arg = arg-1;
+}
+return head.next.i;
+""");
+        try { code.parse().opto().typeCheck(); fail(); }
+        catch( Exception e ) { assertEquals("Might be null accessing 'next'",e.getMessage()); }
+    }
+
+    @Test
+    public void testLinkedList1() {
+        CodeGen code = new CodeGen(
+"""
+struct LLI { LLI? next; int i; };
+LLI? !head = null;
+while( arg ) {
+    LLI !x = new LLI;
+    x.next = head;
+    x.i = arg;
+    head = x;
+    arg = arg-1;
+}
+if( !head ) return 0;
+LLI? next = head.next;
+if( next==null ) return 1;
+return next.i;
+""");
+        code.parse().opto();
+        assertEquals("return Phi(Region,0,1,.i);", code.print());
+        assertEquals("2", Eval2.eval(code,  3));
+    }
+
+    @Test
+    public void testCoRecur() {
+        CodeGen code = new CodeGen(
+"""
+struct int0 { int i; flt0? f; };
+struct flt0 { flt f; int0? i; };
+int0 !i0 = new int0;
+i0.i = 17;
+flt0 !f0 = new flt0;
+f0.f = 3.14;
+i0.f = f0;
+f0.i = i0;
+return f0.i.f.i.i;
+""");
+        code.parse().opto();
+        assertEquals("return 17;", code.print());
+    }
+
+    @Test
+    public void testNullRef0() {
+        CodeGen code = new CodeGen(
+"""
+struct N { N? next; int i; };
+N n = new N;
+return n.next;
+""");
+        code.parse().opto();
+        assertEquals("return null;", code.print());
+    }
+
+    @Test
+    public void testNullRef1() {
+        CodeGen code = new CodeGen(
+"""
+struct M { int m; };
+struct N { M next; int i; };
+N n = new N { next = new M; };
+return n.next;
+""");
+        code.parse().opto();
+        assertEquals("return (const)M;", code.print());
+    }
+
+    @Test
+    public void testNullRef2() {
+        CodeGen code = new CodeGen(
+"""
+struct M { int m; };
+struct N { M next; int i; };
+N n = new N { next = null; }
+return n.next;
+""");
+        try { code.parse().opto(); fail(); }
+        catch( Exception e ) { assertEquals("Type null is not of declared type *M",e.getMessage()); }
+    }
+
+    @Test
+    public void testNullRef3() {
+        CodeGen code = new CodeGen(
+"""
+struct N { N? next; int i; };
+N !n = new N;
+n.i = 3.14;
+return n.i;
+""");
+        try { code.parse().opto(); fail(); }
+        catch( Exception e ) { assertEquals("Type 3.14 is not of declared type int",e.getMessage()); }
+    }
+
+    @Test
+    public void testNullRef4() {
+        CodeGen code = new CodeGen("-null-5/null-5;");
+        try { code.parse().opto().typeCheck(); fail(); }
+        catch( Exception e ) { assertEquals("Cannot 'Add' null",e.getMessage()); }
+    }
+
+    @Test public void testNullRef5() {
+        CodeGen code = new CodeGen("return null+42;");
+        try { code.parse().opto().typeCheck(); fail(); }
+        catch( Exception e ) { assertEquals("Cannot 'Add' null",e.getMessage()); }
+    }
+
+    @Test
+    public void testEmpty() {
+        CodeGen code = new CodeGen(
+"""
+struct S{};
+""");
+        code.parse().opto();
+        assertEquals("return 0;", code.print());
+        assertEquals("0", Eval2.eval(code,  0));
+    }
+
+    @Test
+    public void testForwardRef0() {
+        CodeGen code = new CodeGen(
+"""
+struct S1 { S2? s; };
+return new S2;
+""");
+        try { code.parse().opto(); fail(); }
+        catch( Exception e ) { assertEquals("Unknown struct type 'S2'",e.getMessage()); }
+    }
+
+    @Test
+    public void testForwardRef1() {
+        CodeGen code = new CodeGen(
+"""
+struct S1 { S2? s; };
+struct S2 { int x; };
+return new S1.s=new S2;
+""");
+        code.parse().opto();
+        assertEquals("return S2;", code.print());
+    }
+
+    @Test
+    public void testcheckNull() {
+        CodeGen code = new CodeGen(
+"""
+struct I {int i;};
+struct P { I? pi; };
+P !p1 = new P;
+P !p2 = new P;
+p2.pi = new I;
+p2.pi.i = 2;
+if (arg) p1 = new P;
+return p1.pi.i + 1;
+""");
+        try { code.parse().opto().typeCheck();  fail(); }
+        catch( Exception e ) {  assertEquals("Might be null accessing 'i'",e.getMessage());  }
+    }
+
+    @Test
+    public void testCoRecur2() {
+        CodeGen code = new CodeGen(
+"""
+struct A { L? a; T? b; F? c; };  A? !a = new A;
+struct B { M? a; U? b; G? c; };  B? !b = new B;
+struct C { N? a; V? b; H? c; };  C? !c = new C;
+struct D { O? a; W? b; I? c; };  D? !d = new D;
+struct E { P? a; X? b; J? c; };  E? !e = new E;
+struct F { Q? a; Y? b; K? c; };  F? !f = new F;
+struct G { R? a; Z? b; L? c; };  G? !g = new G;
+struct H { S? a; A? b; M? c; };  H? !h = new H;
+struct I { T? a; B? b; N? c; };  I? !i = new I;
+struct J { U? a; C? b; O? c; };  J? !j = new J;
+struct K { V? a; D? b; P? c; };  K? !k = new K;
+struct L { W? a; E? b; Q? c; };  L? !l = new L;
+struct M { X? a; F? b; R? c; };  M? !m = new M;
+struct N { Y? a; G? b; S? c; };  N? !n = new N;
+struct O { Z? a; H? b; T? c; };  O? !o = new O;
+struct P { A? a; I? b; U? c; };  P? !p = new P;
+struct Q { B? a; J? b; V? c; };  Q? !q = new Q;
+struct R { C? a; K? b; W? c; };  R? !r = new R;
+struct S { D? a; L? b; X? c; };  S? !s = new S;
+struct T { E? a; M? b; Y? c; };  T? !t = new T;
+struct U { F? a; N? b; Z? c; };  U? !u = new U;
+struct V { G? a; O? b; A? c; };  V? !v = new V;
+struct W { H? a; P? b; B? c; };  W? !w = new W;
+struct X { I? a; Q? b; C? c; };  X? !x = new X;
+struct Y { J? a; R? b; D? c; };  Y? !y = new Y;
+struct Z { K? a; S? b; E? c; };  Z? !z = new Z;
+
+a.a=l;  a.b=t; a.c=f;
+b.a=m;  b.b=u; b.c=g;
+c.a=n;  c.b=v; c.c=h;
+d.a=o;  d.b=w; d.c=i;
+e.a=p;  e.b=x; e.c=j;
+f.a=q;  f.b=y; f.c=k;
+g.a=r;  g.b=z; g.c=l;
+h.a=s;  h.b=a; h.c=m;
+i.a=t;  i.b=b; i.c=n;
+j.a=u;  j.b=c; j.c=o;
+k.a=v;  k.b=d; k.c=p;
+l.a=w;  l.b=e; l.c=q;
+m.a=x;  m.b=f; m.c=r;
+n.a=y;  n.b=g; n.c=s;
+o.a=z;  o.b=h; o.c=t;
+p.a=a;  p.b=i; p.c=u;
+q.a=b;  q.b=j; q.c=v;
+r.a=c;  r.b=k; r.c=w;
+s.a=d;  s.b=l; s.c=x;
+t.a=e;  t.b=m; t.c=y;
+u.a=f;  u.b=n; u.c=z;
+v.a=g;  v.b=o; v.c=a;
+w.a=h;  w.b=p; w.c=b;
+x.a=i;  x.b=q; x.c=c;
+y.a=j;  y.b=r; y.c=d;
+z.a=k;  z.b=s; z.c=e;
+
+return a.b.c.a.b.c.a.b.c.a.b.c.a.b.c.a.b.c;
+
+""");
+        code.parse().opto().typeCheck().GCM().localSched();
+        assertEquals("return R;", code._stop.toString());
+        assertEquals("R{a=C{a=N{a=Y{a=J{a=U{a=F{a=Q{a=B{a=M{a=X{a=I{a=T{a=E{a=P{a=A{a=L{a=W{a=H{a=S{a=D{a=O{a=Z{a=K{a=V{a=G{a=$cyclic,b=$cyclic,c=$cyclic},b=$cyclic,c=$cyclic},b=$cyclic,c=$cyclic},b=$cyclic,c=$cyclic},b=$cyclic,c=$cyclic},b=$cyclic,c=$cyclic},b=$cyclic,c=$cyclic},b=$cyclic,c=$cyclic},b=$cyclic,c=$cyclic},b=$cyclic,c=$cyclic},b=$cyclic,c=$cyclic},b=$cyclic,c=$cyclic},b=$cyclic,c=$cyclic},b=$cyclic,c=$cyclic},b=$cyclic,c=$cyclic},b=$cyclic,c=$cyclic},b=$cyclic,c=$cyclic},b=$cyclic,c=$cyclic},b=$cyclic,c=$cyclic},b=$cyclic,c=$cyclic},b=$cyclic,c=$cyclic},b=$cyclic,c=$cyclic},b=$cyclic,c=$cyclic},b=$cyclic,c=$cyclic},b=$cyclic,c=$cyclic},b=$cyclic,c=$cyclic}", Eval2.eval(code,  0));
+    }
+
+}
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/Chapter14Test.java b/chapter22/src/test/java/com/seaofnodes/simple/Chapter14Test.java
new file mode 100644
index 00000000..7af35b56
--- /dev/null
+++ b/chapter22/src/test/java/com/seaofnodes/simple/Chapter14Test.java
@@ -0,0 +1,226 @@
+package com.seaofnodes.simple;
+
+import com.seaofnodes.simple.codegen.CodeGen;
+import com.seaofnodes.simple.node.StopNode;
+import org.junit.Test;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.fail;
+
+public class Chapter14Test {
+
+    @Test
+    public void testJig() {
+        CodeGen code = new CodeGen(
+"""
+return 3.14;
+""");
+        code.parse().opto();
+        assertEquals("return 3.14;", code.print());
+        assertEquals("3.14", Eval2.eval(code,  0));
+    }
+
+    @Test
+    public void testRange() {
+        CodeGen code = new CodeGen(
+"""
+int b;
+if( arg ) b=1; else b=0;
+int c = 99;
+if( b < 0 ) c = -1;
+if( b > 2 ) c =  1;
+return c;
+""");
+        code.parse().opto();
+        assertEquals("return 99;", code.print());
+        assertEquals("99", Eval2.eval(code,  0));
+    }
+
+    @Test
+    public void testU8() {
+        CodeGen code = new CodeGen(
+"""
+u8 b = 123;
+b = b + 456;// Truncate
+return b;
+""");
+        code.parse().opto();
+        assertEquals("return 67;", code.print());
+        assertEquals("67", Eval2.eval(code,  0));
+    }
+
+
+    @Test
+    public void testU8While() {
+        CodeGen code = new CodeGen(
+"""
+u8 b = 123;
+while( b ) b = b + 456;// Truncate
+return b;
+""");
+        code.parse().opto();
+        assertEquals("return 0;", code.print());
+    }
+
+    @Test
+    public void testU1() {
+        CodeGen code = new CodeGen(
+"""
+bool b = 123;
+b = b + 456;// Truncate
+u1 c = b;   // No more truncate needed
+return c;
+""");
+        code.parse().opto();
+        assertEquals("return 1;", code.print());
+        assertEquals("1", Eval2.eval(code,  0));
+    }
+
+    @Test
+    public void testAnd() {
+        CodeGen code = new CodeGen(
+"""
+int b = 123;
+b = b+456 & 31;                 // Precedence
+return b;
+""");
+        code.parse().opto();
+        assertEquals("return 3;", code.print());
+        assertEquals("3", Eval2.eval(code,  0));
+    }
+
+    @Test
+    public void testRefLoad() {
+        CodeGen code = new CodeGen(
+"""
+struct Foo { u1 b; };
+Foo !f = new Foo;
+f.b = 123;
+return f.b;
+""");
+        code.parse().opto();
+        assertEquals("return 1;", code.print());
+        assertEquals("1", Eval2.eval(code,  0));
+    }
+
+    @Test
+    public void testSigned() {
+        CodeGen code = new CodeGen(
+"""
+i8 b = 255;                     // Chopped
+return b;                       // Sign extend
+""");
+        code.parse().opto();
+        assertEquals("return -1;", code.print());
+        assertEquals("-1", Eval2.eval(code,  0));
+    }
+
+    @Test
+    public void testI8() {
+        CodeGen code = new CodeGen(
+"""
+i8 b = arg;
+b = b + 1;// Truncate
+return b;
+""");
+        code.parse().opto();
+        assertEquals("return (((((arg<<56)>>56)+1)<<56)>>56);", code.print());
+        assertEquals("1", Eval2.eval(code, 0));
+        assertEquals("-128", Eval2.eval(code, 127));
+    }
+
+    @Test
+    public void testMask() {
+        CodeGen code = new CodeGen(
+"""
+u16 mask = (1<<16)-1;           // AND mask
+int c = 123456789 & mask;
+return c;                       //
+""");
+        code.parse().opto();
+        assertEquals("return 52501;", code.print());
+        assertEquals("52501", Eval2.eval(code,  0));
+    }
+
+    @Test
+    public void testOr() {
+        CodeGen code = new CodeGen(
+"""
+return (arg | 123 ^ 456) >>> 1;
+""");
+        code.parse().opto();
+        assertEquals("return (((arg|123)^456)>>>1);", code.print());
+        assertEquals("217", Eval2.eval(code,  0));
+    }
+
+    @Test
+    public void testMaskFloat() {
+        CodeGen code = new CodeGen(
+"""
+flt f = arg;
+arg = f & 1;
+return arg;
+""");
+        try { code.parse().opto().typeCheck(); fail(); }
+        catch( Exception e ) { assertEquals("Cannot '&' flt",e.getMessage()); }
+    }
+
+    @Test
+    public void testCloneAnd() {
+        CodeGen code = new CodeGen("""
+int v0=0;
+u32 v1 = 1&(1<<arg)&(1<<arg);
+while(arg) v1=-v0;
+while(v1) break;
+return v1;
+""");
+        code.parse().opto();
+        assertEquals("return Phi(Loop,(((1<<arg)&1)&Shl),0);", code.print());
+        assertEquals("1", Eval2.eval(code,  0));
+    }
+
+    @Test
+    public void testAndHigh() {
+        CodeGen code = new CodeGen("""
+int v0=0;
+if(0&0>>>0) {
+    while(0) {
+        u8 v1=0;
+        v0=0>>>0;
+        v1=arg;
+        while(v1+0) {}
+    }
+}
+return v0;
+""");
+        code.parse().opto();
+        assertEquals("return 0;", code.print());
+        assertEquals("0", Eval2.eval(code,  0));
+    }
+
+    @Test
+    public void testTypes() {
+        CodeGen code = new CodeGen(
+"""
+i8  xi8  = 123456789;  if( xi8  !=        21 ) return -8;
+i16 xi16 = 123456789;  if( xi16 !=    -13035 ) return -16;
+i32 xi32 = 123456789;  if( xi32 != 123456789 ) return -32;
+i64 xi64 = 123456789;  if( xi64 != 123456789 ) return -64;
+int xint = 123456789;  if( xint != 123456789 ) return -64;
+
+u1  ui1  = 123456789;  if( ui1  !=         1 ) return 1;
+u8  ui8  = 123456789;  if( ui8  !=        21 ) return 8;
+u16 ui16 = 123456789;  if( ui16 !=     52501 ) return 16;
+u32 ui32 = 123456789;  if( ui32 != 123456789 ) return 32;
+
+flt fflt = 3.141592653589793;  if( fflt != 3.141592653589793 ) return 3;
+f64 ff64 = 3.141592653589793;  if( ff64 != 3.141592653589793 ) return 3;
+f32 ff32 = 3.141592653589793;  if( ff32 != 3.1415927410125732) return 5;
+
+return 0;
+""");
+        code.parse().opto();
+        assertEquals("return 0;", code.print());
+        assertEquals("0", Eval2.eval(code,  0));
+    }
+
+}
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/Chapter15Test.java b/chapter22/src/test/java/com/seaofnodes/simple/Chapter15Test.java
new file mode 100644
index 00000000..8b138b46
--- /dev/null
+++ b/chapter22/src/test/java/com/seaofnodes/simple/Chapter15Test.java
@@ -0,0 +1,354 @@
+package com.seaofnodes.simple;
+
+import com.seaofnodes.simple.codegen.CodeGen;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import org.junit.Test;
+import static org.junit.Assert.*;
+
+public class Chapter15Test {
+
+    @Test
+    public void testJig() {
+        CodeGen code = new CodeGen(
+"""
+return 3.14;
+""");
+        code.parse().opto();
+        assertEquals("return 3.14;", code.print());
+        assertEquals("3.14", Eval2.eval(code,  0));
+    }
+
+    @Test
+    public void testCyclic() {
+        CodeGen code = new CodeGen(
+"""
+struct C { C? l; };
+C !c = new C;
+c.l = c;
+return c;
+""");
+        code.parse().opto();
+        assertEquals("return C;", code.print());
+        assertEquals("C{l=$cyclic}", Eval2.eval(code,  0));
+    }
+
+    @Test
+    public void testSafetyCheck() {
+        CodeGen code = new CodeGen(
+"""
+u8[] old = new u8[0];
+u8[] !output = new u8[1];
+int i = 0;
+while (i < old#) {
+    output[i] = old[i];
+    i = i + 1;
+}
+output[i] = 1;
+return output;
+""");
+        code.parse().opto();
+        assertEquals("return [u8];", code.print());
+        assertEquals("\u0001", Eval2.eval(code,  0));
+    }
+
+    @Test
+    public void testBasic1() {
+        CodeGen code = new CodeGen(
+"""
+int[] is = new int[2];
+return is[1];
+""");
+        code.parse().opto();
+        assertEquals("return 0;", code.print());
+        assertEquals("0", Eval2.eval(code,  0));
+    }
+
+    @Test
+    public void testBasic2() {
+        CodeGen code = new CodeGen(
+"""
+int[] is = new int[2];
+int[] is2 = new int[2];
+return is[1];
+""");
+        code.parse().opto();
+        assertEquals("return 0;", code.print());
+        assertEquals("0", Eval2.eval(code,  0));
+    }
+
+    @Test
+    public void testBasic3() {
+        CodeGen code = new CodeGen(
+"""
+int[] !a = new int[2];
+a[0] = 1;
+a[1] = 2;
+return a[0];
+""");
+        code.parse().opto();
+        assertEquals("return 1;", code.print());
+        assertEquals("1", Eval2.eval(code,  0));
+    }
+
+    @Test
+    public void testBasic4() {
+        CodeGen code = new CodeGen(
+"""
+struct A { int i; };
+A?[] !a = new A?[2];
+return a;
+""");
+        code.parse().opto();
+        assertEquals("return [*A?];", code.print());
+        assertEquals("*A {int !i; }?[ null,null]", Eval2.eval(code, 0));
+    }
+
+    @Test
+    public void testBasic5() {
+        CodeGen code = new CodeGen(
+"""
+struct S { int x; flt y; };
+// A new S
+S !s = new S; s.x=99; s.y = 3.14;
+
+// Double-d array of Ss.  Fill in one row.
+S?[]?[] !iss = new S?[]?[2];
+iss[0] = new S?[7];
+iss[0][2] = s;
+
+// Now pull out the filled-in value, with null checks
+flt rez;
+S?[]? is = iss[arg];
+if( !is ) rez = 1.2;
+else {
+    S? i = is[2];
+    if( !i ) rez = 2.3;
+    else rez = i.y;
+}
+return rez;
+""");
+        code.parse().opto();
+        assertEquals("return Phi(Region,1.2,.y,2.3);", code.print());
+        assertEquals("3.14", Eval2.eval(code, 0));
+        assertEquals("1.2", Eval2.eval(code, 1));
+    }
+
+    @Test
+    public void testBasic6() {
+        CodeGen code = new CodeGen(
+"""
+struct S { int x; flt y; };
+// A new S
+S !s = new S; s.x=99; s.y = 3.14;
+
+// Double-d array of Ss.  Fill in one row.
+S?[]?[] !iss = new S?[]?[2];
+iss[0] = new S?[7];
+iss[0][2] = s;
+
+// Now pull out the filled-in value, with null checks
+flt rez = 1.2;
+if( iss[arg] )
+    if( iss[arg][2] )
+        rez = iss[arg][2].y;
+return rez;""");
+        code.parse().opto().typeCheck();
+        assertEquals("return Phi(Region,1.2,1.2,.y);", code.print());
+        assertEquals("3.14", Eval2.eval(code,  0));
+        try { Eval2.eval(code, 10); fail(); } // Fails AIOOBE in Eval2, no range checks
+        catch( Exception e ) { assertEquals("Index 10 out of bounds for length 2",e.getMessage()); }
+    }
+
+    @Test
+    public void testTree() {
+        CodeGen code = new CodeGen(
+"""
+// Can we define a forward-reference array?
+struct Tree { Tree?[]? _kids; };
+Tree !root = new Tree;
+root._kids = new Tree?[2]; // NO BANG SO ARRAY IS OF IMMUTABLE TREES????
+root._kids[0] = new Tree;
+return root;
+""");
+        code.parse().opto();
+        assertEquals("return Tree;", code.print());
+        assertEquals("Tree{_kids=*Tree?[ Tree{_kids=null},null]}", Eval2.eval(code,  0));
+    }
+
+    @Test
+    public void testNestedStructAddMemProj() {
+        CodeGen code = new CodeGen(
+"""
+struct S { int a; int[] b; };
+return 0;
+""");
+        code.parse().opto();
+        assertEquals("return 0;", code.print());
+    }
+
+    @Test
+    public void testRollingSum() {
+        CodeGen code = new CodeGen(
+"""
+int[] !ary = new int[arg];
+// Fill [0,1,2,3,4,...]
+int i=0;
+while( i < ary# ) {
+    ary[i] = i;
+    i = i+1;
+}
+// Fill [0,1,3,6,10,...]
+i=0;
+while( i < ary# - 1 ) {
+    ary[i+1] = ary[i+1] + ary[i];
+    i = i+1;
+}
+return ary[1] * 1000 + ary[3]; // 1 * 1000 + 6
+""");
+        code.parse().opto();
+        assertEquals("return (.[]+(.[]*1000));", code.print());
+        assertEquals("1006", Eval2.eval(code,  4));
+    }
+
+    @Test
+    public void sieveOEratosthenes() throws IOException {
+        String src = Files.readString(Path.of("src/test/java/com/seaofnodes/simple/progs/sieve.smp"));
+        CodeGen code = new CodeGen(src+"return sieve(arg);");
+        code.parse().opto();
+        assertEquals("return [u32];", code.print());
+        assertEquals("u32[ 2,3,5,7,11,13,17,19]",Eval2.eval(code, 20));
+    }
+
+    @Test
+    public void testNewNodeInit() {
+        CodeGen code = new CodeGen(
+"""
+struct S {int i; flt f;};
+S !s1 = new S;
+S !s2 = new S;
+s2.i = 3;
+s2.f = 2.0;
+if (arg) s1 = new S;
+return s1.i + s1.f;
+""");
+        code.parse().opto();
+        assertEquals("return ((flt).i+.f);", code.print());
+        assertEquals("0.0", Eval2.eval(code,  0));
+    }
+
+
+    @Test
+    public void testBad0() {
+        CodeGen code = new CodeGen(
+"""
+return new flt;
+""");
+        try { code.parse().opto(); fail(); }
+        catch( Exception e ) { assertEquals("Cannot allocate a flt",e.getMessage()); }
+    }
+
+    @Test
+    public void testBad1() {
+        CodeGen code = new CodeGen(
+"""
+int is = new int[2];
+""");
+        try { code.parse().opto(); fail(); }
+        catch( Exception e ) { assertEquals("Type *[int] is not of declared type int",e.getMessage()); }
+    }
+
+    @Test
+    public void testBad2() {
+        CodeGen code = new CodeGen(
+"""
+int[] is = new int[3.14];
+return is[1];
+""");
+        try { code.parse().opto(); fail(); }
+        catch( Exception e ) { assertEquals("Cannot allocate an array with length 3.14",e.getMessage()); }
+    }
+
+    @Test
+    public void testBad3() {
+        CodeGen code = new CodeGen("""
+int[] is = new int[arg];
+return is[1];
+""");
+        code.parse().opto();
+        assertEquals("return 0;", code.print());
+        assertEquals("0", Eval2.eval(code,  4));
+        try { Eval2.eval(code,-1); fail(); }
+        catch( NegativeArraySizeException e ) { assertEquals("-1",e.getMessage()); }
+        // This test will not pass (i.e., failed range-check) until we have range checks.
+        // Without the range check, the load `is[1]` optimizes against the `new int[]`
+        // and assumes it loads a zero then folds away, and the Eval2 never sees an OOB load.
+        //try { Eval2.eval(code,0); fail(); }
+        //catch( ArrayIndexOutOfBoundsException e ) { assertEquals("Array index 1 out of bounds for array length 0",e.getMessage()); }
+    }
+
+    @Test
+    public void testProgress() {
+        CodeGen code = new CodeGen("""
+i8 v1=0&0;
+u8 v2=0;
+byte v4=0;
+if(0) {}
+while(v2<0) {
+    v4=0-v1;
+    break;
+}
+int v5=0&0;
+while(v5+(0&0)) {
+    int v7=0&0;
+    while(v7)
+        v4=0>>>v5;
+    while(v1)
+        return 0;
+}
+return v1;
+""");
+        code.parse().opto();
+        assertEquals("return 0;", code.print());
+        assertEquals("0", Eval2.eval(code,  0));
+    }
+
+    @Test
+    public void testSharpNot() {
+        CodeGen code = new CodeGen(
+"""
+if(0>>0) {}
+while(0) {}
+u32 v7=0;
+int v8=0;
+while(0<--1>>>---(v7*0==v8)) {}
+""");
+        code.parse().opto();
+        assertEquals("return 0;", code.print());
+    }
+
+
+    @Test
+    public void testProgress2() {
+        CodeGen code = new CodeGen(
+"""
+if(1) {}
+else {
+        while(arg>>>0&0>>>0) {}
+    byte v3=0>>>0;
+                while(0) {}
+        int v7=0>>>0;
+        while(v7<0>>>0) {
+                    while(0+v7<=0) if(1) arg=-12;
+            if(arg) {
+                v3=arg+v3+0;
+                arg=0;
+            }
+        }
+}
+""");
+        code.parse().opto();
+        assertEquals("return 0;", code.print());
+    }
+}
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/Chapter16Test.java b/chapter22/src/test/java/com/seaofnodes/simple/Chapter16Test.java
new file mode 100644
index 00000000..930624e5
--- /dev/null
+++ b/chapter22/src/test/java/com/seaofnodes/simple/Chapter16Test.java
@@ -0,0 +1,261 @@
+package com.seaofnodes.simple;
+
+import com.seaofnodes.simple.codegen.CodeGen;
+import com.seaofnodes.simple.evaluator.Evaluator;
+import com.seaofnodes.simple.node.StopNode;
+import org.junit.Test;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.fail;
+
+public class Chapter16Test {
+
+    @Test
+    public void testJig() {
+        CodeGen code = new CodeGen(
+"""
+return 3.14;
+""");
+        code.parse().opto();
+        assertEquals("return 3.14;", code.print());
+        assertEquals("3.14", Eval2.eval(code,  0));
+    }
+
+
+    @Test
+    public void testMulti0() {
+        CodeGen code = new CodeGen(
+"""
+int x, y;
+return x+y;
+""");
+        code.parse().opto();
+        assertEquals("return 0;", code.print());
+        assertEquals("0", Eval2.eval(code,  0));
+    }
+    @Test
+    public void testMulti1() {
+        CodeGen code = new CodeGen(
+"""
+int x=2, y=x+1;
+return x+y;
+""");
+        code.parse().opto();
+        assertEquals("return 5;", code.print());
+        assertEquals("5", Eval2.eval(code,  0));
+    }
+
+//    @Test
+//    public void testFinal0() {
+//        CodeGen code = new CodeGen(
+//"""
+//int !x=2;
+//x=3;
+//return x;
+//""");
+//        try { code.parse().opto(); fail(); }
+//        catch( Exception e ) { assertEquals("Cannot reassign final 'x'",e.getMessage()); }
+//    }
+
+    @Test
+    public void testFinal1() {
+        CodeGen code = new CodeGen(
+"""
+int x=2, y=3;
+if( arg ) { int x = y; x = x*x; y=x; } // Shadow final x
+return y;
+""");
+        code.parse().opto();
+        assertEquals("return Phi(Region,9,3);", code.print());
+        assertEquals("3", Eval2.eval(code, 0));
+        assertEquals("9", Eval2.eval(code, 1));
+    }
+
+    @Test
+    public void testConstruct0() {
+        CodeGen code = new CodeGen("""
+struct X { int x=3; };
+X z = new X;
+return z.x;
+""");
+        code.parse().opto();
+        assertEquals("return 3;", code.print());
+        assertEquals("3", Eval2.eval(code,  0));
+    }
+
+    @Test
+    public void testConstruct1() {
+        CodeGen code = new CodeGen("""
+struct X { int !x; };
+X z = new X { x=3; };
+return z.x;
+""");
+        code.parse().opto();
+        assertEquals("return 3;", code.print());
+        assertEquals("3", Eval2.eval(code,  0));
+    }
+
+    @Test
+    public void testConstruct2() {
+        CodeGen code = new CodeGen("""
+struct X { int x=3; };
+X z = new X { x = 4; };
+return z.x;
+""");
+        code.parse().opto();
+        assertEquals("return 4;", code.print());
+        assertEquals("4", Eval2.eval(code,  0));
+    }
+
+
+    @Test
+    public void testStructFinal0() {
+        CodeGen code = new CodeGen("""
+struct Point { int !x, !y; };
+Point p = new Point { x=3; y=4; };
+return p;
+""");
+        code.parse().opto();
+        assertEquals("return (const)Point;", code.print());
+        assertEquals("Point{x=3,y=4}", Eval2.eval(code,  0));
+    }
+
+    @Test
+    public void testStructFinal1() {
+        CodeGen code = new CodeGen("""
+struct Point { int x=3, y=4; };
+Point p = new Point { x=5; y=6; };
+p.x++;
+return p;
+""");
+        try { code.parse().opto().typeCheck(); fail(); }
+        catch( Exception e ) { assertEquals("Cannot modify final field 'x'",e.getMessage()); }
+    }
+
+    @Test
+    public void testStructFinal2() {
+        CodeGen code = new CodeGen("""
+struct Point { int x=3, y=4; };
+Point p = new Point;
+p.x++;
+return p;
+""");
+        try { code.parse().opto().typeCheck(); fail(); }
+        catch( Exception e ) { assertEquals("Cannot modify final field 'x'",e.getMessage()); }
+    }
+
+    @Test
+    public void testStructFinal3() {
+        CodeGen code = new CodeGen("""
+struct Point { var x; var y; };
+Point p = new Point;
+p.x++;
+return p;
+""");
+        try { code.parse().opto(); fail(); }
+        catch( Exception e ) { assertEquals("'Point' is not fully initialized, field 'x' needs to be set in a constructor",e.getMessage()); }
+    }
+
+    @Test
+    public void testStructFinal4() {
+        CodeGen code = new CodeGen("""
+struct Point { val x=3; val y=4; };
+Point p = new Point;
+p.x++;
+return p;
+""");
+        try { code.parse().opto(); fail(); }
+        catch( Exception e ) { assertEquals("Cannot reassign final 'x'",e.getMessage()); }
+    }
+
+    @Test
+    public void testStructFinal5() {
+        CodeGen code = new CodeGen("""
+struct Point { var x=3; var y=4; };
+Point !p = new Point;
+p.x++;
+return p;
+""");
+        code.parse().opto();
+        assertEquals("return Point;", code.print());
+        assertEquals("Point{x=4,y=4}", Eval2.eval(code,  0));
+    }
+
+    // Same as the Chapter13 test with the same name, but using the new
+    // constructor syntax
+    @Test
+    public void testLinkedList1() {
+        CodeGen code = new CodeGen(
+"""
+struct LLI { LLI? next; int i; };
+LLI? !head = null;
+while( arg ) {
+    head = new LLI { next=head; i=arg; };
+    arg = arg-1;
+}
+if( !head ) return 0;
+LLI? next = head.next;
+if( !next ) return 1;
+return next.i;
+""");
+        code.parse().opto();
+        assertEquals("return Phi(Region,0,1,.i);", code.print());
+        assertEquals("0", Eval2.eval(code,  0));
+        assertEquals("1", Eval2.eval(code,  1));
+        assertEquals("2", Eval2.eval(code,  3));
+    }
+
+    @Test
+    public void testLinkedList2() {
+        CodeGen code = new CodeGen(
+"""
+struct LLI { LLI? next; int i; };
+LLI? !head = null;
+while( arg ) {
+    head = new LLI {
+        next=head;
+        // Any old code in the constructor
+        int !tmp=arg;
+        while( arg > 10 ) {
+            tmp = tmp + arg;
+            arg = arg - 1;
+        }
+        i=tmp;
+    };
+    arg = arg-1;
+}
+if( !head ) return 0;
+LLI? next = head.next;
+if( !next ) return 1;
+return next.i;
+""");
+        code.parse().opto();
+        assertEquals("return Phi(Region,0,1,.i);", code.print());
+        assertEquals("0", Eval2.eval(code,  0));
+        assertEquals("1", Eval2.eval(code,  1));
+        assertEquals("2", Eval2.eval(code, 11));
+    }
+
+    @Test
+    public void testSquare() {
+        CodeGen code = new CodeGen(
+"""
+struct Square {
+    flt !side = arg;
+    // Newtons approximation to the square root, computed in a constructor.
+    // The actual allocation will copy in this result as the initial
+    // value for 'diag'.
+    flt !diag = arg*arg/2;
+    while( 1 ) {
+        flt next = (side/diag + diag)/2;
+        if( next == diag ) break;
+        diag = next;
+    }
+};
+return new Square;
+""");
+        code.parse().opto();
+        assertEquals("return Square;", code.print());
+        assertEquals("Square{side=3.0,diag=1.7320508075688772}", Eval2.eval(code,  3));
+        assertEquals("Square{side=4.0,diag=2.0}", Eval2.eval(code, 4));
+    }
+}
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/Chapter17Test.java b/chapter22/src/test/java/com/seaofnodes/simple/Chapter17Test.java
new file mode 100644
index 00000000..78515083
--- /dev/null
+++ b/chapter22/src/test/java/com/seaofnodes/simple/Chapter17Test.java
@@ -0,0 +1,555 @@
+package com.seaofnodes.simple;
+
+import com.seaofnodes.simple.codegen.CodeGen;
+import org.junit.Test;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.fail;
+
+public class Chapter17Test {
+
+    @Test
+    public void testJig() {
+        CodeGen code = new CodeGen(
+"""
+return 1;
+""");
+        code.parse().opto().typeCheck();
+        assertEquals("return 1;", code.print());
+        assertEquals("1", Eval2.eval(code,  0));
+    }
+
+
+    // ---------------------------------------------------------------
+    @Test
+    public void testInc0() {
+        CodeGen code = new CodeGen("""
+return arg++;
+""");
+        code.parse().opto();
+        assertEquals("return arg;", code.print());
+        assertEquals("0", Eval2.eval(code, 0));
+    }
+
+    @Test
+    public void testInc1() {
+        CodeGen code = new CodeGen("""
+return arg+++arg++;
+""");
+        code.parse().opto();
+        assertEquals("return ((arg<<1)+1);", code.print());
+        assertEquals("1", Eval2.eval(code, 0));
+    }
+
+    @Test
+    public void testInc2() {
+        CodeGen code = new CodeGen("""
+//   -(arg--)-(arg--)
+return -arg---arg--;
+""");
+        code.parse().opto();
+        assertEquals("return (-((arg<<1)+-1));", code.print());
+        assertEquals("1", Eval2.eval(code, 0));
+    }
+
+    @Test
+    public void testInc3() {
+        CodeGen code = new CodeGen("""
+int[] !xs = new int[arg];
+xs[0]++;
+xs[1]++;
+return xs[0];
+""");
+        code.parse().opto();
+        assertEquals("return 1;", code.print());
+        assertEquals("1", Eval2.eval(code, 2));
+    }
+
+    @Test
+    public void testInc4() {
+        CodeGen code = new CodeGen("""
+u8[] !xs = new u8[1];
+xs[0]--;
+return xs[0];
+""");
+        code.parse().opto();
+        assertEquals("return 255;", code.print());
+        assertEquals("255", Eval2.eval(code, 2));
+    }
+
+    @Test
+    public void testInc5() {
+        CodeGen code = new CodeGen("""
+struct S { u16 x; };
+S !s = new S;
+s.x--;
+return s.x;
+""");
+        code.parse().opto();
+        assertEquals("return 65535;", code.print());
+        assertEquals("65535", Eval2.eval(code, 2));
+    }
+
+    @Test
+    public void testInc6() {
+        CodeGen code = new CodeGen("return --arg;");
+        code.parse().opto();
+        assertEquals("return (arg+-1);", code.print());
+        assertEquals("-1", Eval2.eval(code, 0));
+    }
+
+    @Test
+    public void testInc7() {
+        CodeGen code = new CodeGen("u8 x=0; return --x;");
+        code.parse().opto();
+        assertEquals("return 255;", code.print());
+        assertEquals("255", Eval2.eval(code, 0));
+    }
+
+    @Test
+    public void testInc8() {
+        CodeGen code = new CodeGen("int x; x+=2; return x+=3;");
+        code.parse().opto();
+        assertEquals("return 5;", code.print());
+        assertEquals("5", Eval2.eval(code, 0));
+    }
+
+    @Test
+    public void testInc9() {
+        CodeGen code = new CodeGen("flt x = 1.5; x++; return x;");
+        code.parse().opto();
+        assertEquals("return 2.5f;", code.print());
+        assertEquals("2.5", Eval2.eval(code, 0));
+    }
+
+    @Test public void testInt10() {
+        CodeGen code = new CodeGen("flt x = 1.5; x++; int i = x; return i;");
+        try { code.parse().opto(); fail(); }
+        catch( Exception e ) { assertEquals("Type 2.5f is not of declared type int",e.getMessage()); }
+    }
+
+
+    // ---------------------------------------------------------------
+    @Test public void testVar0() {
+        CodeGen code = new CodeGen("var d; return d;");
+        try { code.parse().opto(); fail(); }
+        catch( Exception e ) { assertEquals("Syntax error, expected =expression: ;",e.getMessage()); }
+    }
+
+    @Test public void testVar1() {
+        CodeGen code = new CodeGen("val d; return d;");
+        try { code.parse().opto(); fail(); }
+        catch( Exception e ) { assertEquals("Syntax error, expected =expression: ;",e.getMessage()); }
+    }
+
+    @Test public void testVar2() {
+        CodeGen code = new CodeGen("int x; x=3; x++; return x; // Ok, no initializer so x is mutable ");
+        code.parse().opto();
+        assertEquals("return 4;", code.print());
+        assertEquals("4", Eval2.eval(code, 0));
+    }
+
+    @Test public void testVar3() {
+        CodeGen code = new CodeGen("int x=3; x++; return x; // Ok, primitive so x is mutable despite initializer ");
+        code.parse().opto();
+        assertEquals("return 4;", code.print());
+        assertEquals("4", Eval2.eval(code, 0));
+    }
+
+    @Test public void testVar4() {
+        CodeGen code = new CodeGen("struct S{int x;}; S? s; s=new S; s.x++; return s.x; // Ok, no initializer so x is mutable ");
+        code.parse().opto();
+        assertEquals("return 1;", code.print());
+        assertEquals("1", Eval2.eval(code, 0));
+    }
+
+    @Test public void testVar5() {
+        CodeGen code = new CodeGen("struct S{int x;}; S? s; s=new S{x=3;}; s.x++; return s.x; // Ok, no initializer so x is mutable ");
+        code.parse().opto();
+        assertEquals("return 4;", code.print());
+        assertEquals("4", Eval2.eval(code, 0));
+    }
+
+    @Test public void testVar6() {
+        CodeGen code = new CodeGen("struct S{int x;}; S s=new S; s.x++; return s.x; // Error initializer so x is immutable ");
+        try { code.parse().opto().typeCheck(); fail(); }
+        catch( Exception e ) { assertEquals("Cannot modify final field 'x'",e.getMessage()); }
+    }
+
+    @Test public void testVar7() {
+        CodeGen code = new CodeGen("struct S{int x;}; S s=new S{x=3;}; s.x++; return s.x; // Error initializer so x is immutable ");
+        try { code.parse().opto().typeCheck(); fail(); }
+        catch( Exception e ) { assertEquals("Cannot modify final field 'x'",e.getMessage()); }
+    }
+
+    @Test public void testVar8() {
+        CodeGen code = new CodeGen("struct S{int x;}; S !s=new S; s.x++; return s.x; // Ok, has '!' so s.x is mutable ");
+        code.parse().opto();
+        assertEquals("return 1;", code.print());
+        assertEquals("1", Eval2.eval(code, 0));
+    }
+
+    @Test public void testVar9() {
+        CodeGen code = new CodeGen("struct S{int x;}; var s=new S; s.x++; return s.x; // Ok, has var so s.x is mutable ");
+        code.parse().opto();
+        assertEquals("return 1;", code.print());
+        assertEquals("1", Eval2.eval(code, 0));
+    }
+
+    @Test public void testVar10() {
+        CodeGen code = new CodeGen("struct S{int x;}; val s=new S; s.x++; return s.x; // Error, has val so x is immutable ");
+        try { code.parse().opto().typeCheck(); fail(); }
+        catch( Exception e ) { assertEquals("Cannot modify final field 'x'",e.getMessage()); }
+    }
+
+    @Test public void testVar11() {
+        CodeGen code = new CodeGen("""
+struct Bar { int x; };
+Bar !bar = new Bar;
+bar.x = 3; // Ok, bar is mutable
+
+struct Foo { Bar? !bar; int y; };
+Foo !foo = new Foo { bar = bar; };
+foo.bar = bar; // Ok foo is mutable
+foo.bar.x++;   // Ok foo and foo.bar and foo.bar.x are all mutable
+
+val xfoo = foo; // Throw away mutability
+xfoo.bar.x++;   // Error, cannot mutate through xfoo
+ """);
+        try { code.parse().opto().typeCheck(); fail(); }
+        catch( Exception e ) { assertEquals("Cannot modify final field 'x'",e.getMessage()); }
+    }
+
+    @Test public void testVar12() {
+        CodeGen code = new CodeGen("""
+struct Bar { int x; };
+Bar !bar = new Bar;
+bar.x = 3; // Ok, bar is mutable
+
+struct Foo { Bar? !bar; int y; };
+Foo !foo = new Foo;
+foo.bar = bar; // Ok bar is mutable
+foo.bar.x++;   // Ok foo and foo.bar and foo.bar.x are all mutable
+
+val xfoo = foo;        // Throw away mutability
+int x4 = xfoo.bar.x;   // Ok to read through xfoo, gets 4
+foo.bar.x++;           // Bumps to 5
+int x5 = xfoo.bar.x;   // Ok to read through xfoo, gets 5
+return x4*10+x5;
+""");
+        code.parse().opto();
+        assertEquals("return 45;", code.print());
+        assertEquals("45", Eval2.eval(code, 0));
+    }
+
+    @Test
+    public void testVar13() {
+        CodeGen code = new CodeGen("""
+int i,i++;
+""");
+        try { code.parse().opto().typeCheck(); fail(); }
+        catch( Exception e ) { assertEquals("Redefining name 'i'",e.getMessage()); }
+    }
+
+
+    @Test
+    public void testVar14() {
+        CodeGen code = new CodeGen("""
+struct B {};
+struct A { B b; };
+A x = new A {
+    return b; // read before init
+    b = new B;
+};
+""");
+        try { code.parse().opto(); fail(); }
+        catch( Exception e ) { assertEquals("Cannot read uninitialized field 'b'",e.getMessage()); }
+    }
+
+    @Test
+    public void testVar15() {
+        CodeGen code = new CodeGen("""
+struct B {};
+struct A { B b; };
+return new A {
+    if (arg) b = new B; // Constructor ends with partial init of b
+}.b;
+""");
+        try { code.parse().opto(); fail(); }
+        catch( Exception e ) { assertEquals("'A' is not fully initialized, field 'b' needs to be set in a constructor",e.getMessage()); }
+    }
+
+    @Test
+    public void testVar16() {
+        CodeGen code = new CodeGen(
+"""
+struct S{};
+val x = 1;
+val s = new S{x = 2;};
+return x;
+"""
+);
+        try { code.parse().opto().typeCheck(); fail(); }
+        catch( Exception e ) { assertEquals("Cannot reassign final 'x'",e.getMessage()); }
+    }
+
+    @Test
+    public void testVar17() {
+        CodeGen code = new CodeGen(
+"""
+struct Person {
+    bool focused;
+};
+val focus = { Person p ->
+    p.focused = true;
+};
+Person me; // Person !me = new Person;
+focus(me);
+return me;
+"""
+);
+        try { code.parse().opto().typeCheck(); fail(); }
+        catch( Exception e ) { assertEquals("Syntax error, expected =expression: ;",e.getMessage()); }
+    }
+
+    // ---------------------------------------------------------------
+    @Test
+    public void testTrinary0() {
+        CodeGen code = new CodeGen("""
+return arg ? 1 : 2;
+""");
+        code.parse().opto();
+        assertEquals("return Phi(Region,1,2);", code.print());
+        assertEquals("2", Eval2.eval(code, 0));
+        assertEquals("1", Eval2.eval(code, 1));
+    }
+
+    @Test
+    public void testTrinary1() {
+        CodeGen code = new CodeGen("""
+return arg ? 0 : arg;
+""");
+        code.parse().opto();
+        assertEquals("return 0;", code.print());
+        assertEquals("0", Eval2.eval(code, 0));
+    }
+
+    @Test
+    public void testTrinary2() {
+        CodeGen code = new CodeGen("""
+struct Bar { int x; };
+var b = arg ? new Bar : null;
+return b ? b.x++ + b.x++ : -1;
+""");
+        code.parse().opto();
+        assertEquals("return Phi(Region,((.x<<1)+1),-1);", code.print());
+        assertEquals("-1", Eval2.eval(code, 0));
+        assertEquals("1", Eval2.eval(code, 1));
+    }
+
+    @Test
+    public void testTrinary3() {
+        CodeGen code = new CodeGen("""
+struct Bar { int x; };
+var b = arg ? new Bar;
+return b ? b.x++ + b.x++ : -1;
+""");
+        code.parse().opto();
+        assertEquals("return Phi(Region,((.x<<1)+1),-1);", code.print());
+        assertEquals("-1", Eval2.eval(code, 0));
+        assertEquals("1", Eval2.eval(code, 1));
+    }
+
+    @Test
+    public void testTrinary4() {
+        // This test case will benefit from an unzipping transformation
+        CodeGen code = new CodeGen("""
+struct Bar { Bar? next; int x; };
+var b = arg ? new Bar { next = (arg==2) ? new Bar{x=2;}; x=1; };
+return b ? b.next ? b.next.x : b.x; // parses "b ? (b.next ? b.next.x : b.x) : 0"
+""");
+        code.parse().opto();
+        assertEquals("return Phi(Region,.x,0);", code.print());
+        assertEquals("0", Eval2.eval(code, 0));
+        assertEquals("1", Eval2.eval(code, 1));
+        assertEquals("2", Eval2.eval(code, 2));
+    }
+
+    @Test
+    public void testTrinary5() {
+        CodeGen code = new CodeGen("""
+flt f=arg?1:1.2;
+return f;   // missing widening
+""");
+        code.parse().opto();
+        assertEquals("return Phi(Region,1.0f,1.2);", code.print());
+        assertEquals("1.2", Eval2.eval(code,  0));
+    }
+
+
+    @Test
+    public void testTrinary6() {
+        CodeGen code = new CodeGen("""
+struct S{};
+return arg ? 7 : new S;
+""");
+        try { code.parse().opto().typeCheck(); fail(); }
+        catch( Exception e ) { assertEquals("No common type amongst int and reference",e.getMessage()); }
+    }
+
+    // ---------------------------------------------------------------
+    @Test
+    public void testFor0() {
+        CodeGen code = new CodeGen("""
+int sum=0;
+for( int i=0; i<arg; i++ )
+    sum += i;
+return sum;
+""");
+        code.parse().opto();
+        assertEquals("return Phi(Loop,0,(Phi_sum+Phi(Loop,0,(Phi_i+1))));", code.print());
+        assertEquals("3", Eval2.eval(code, 3));
+        assertEquals("45", Eval2.eval(code, 10));
+    }
+    @Test
+    public void testFor1() {
+        CodeGen code = new CodeGen("""
+int sum=0, i=0;
+for( ; i<arg; i++ )
+    sum += i;
+return sum;
+""");
+        code.parse().opto();
+        assertEquals("return Phi(Loop,0,(Phi_sum+Phi(Loop,0,(Phi_i+1))));", code.print());
+        assertEquals("3", Eval2.eval(code, 3));
+        assertEquals("45", Eval2.eval(code, 10));
+    }
+    @Test
+    public void testFor2() {
+        CodeGen code = new CodeGen("""
+int sum=0;
+for( int i=0; ; i++ ) {
+    if( i>=arg ) break;
+    sum += i;
+}
+return sum;
+""");
+        code.parse().opto();
+        assertEquals("return Phi(Loop,0,(Phi_sum+Phi(Loop,0,(Phi_i+1))));", code.print());
+        assertEquals("3", Eval2.eval(code, 3));
+        assertEquals("45", Eval2.eval(code, 10));
+    }
+    @Test
+    public void testFor3() {
+        CodeGen code = new CodeGen("""
+int sum=0;
+for( int i=0; i<arg; )
+    sum += i++;
+return sum;
+""");
+        code.parse().opto();
+        assertEquals("return Phi(Loop,0,(Phi_sum+Phi(Loop,0,(Phi_i+1))));", code.print());
+        assertEquals("3", Eval2.eval(code, 3));
+        assertEquals("45", Eval2.eval(code, 10));
+    }
+    @Test
+    public void testFor4() {
+        CodeGen code = new CodeGen("""
+int sum=0;
+for( int i=0; i<arg; i++ )
+    sum += i;
+return i;
+""");
+        try { code.parse().opto(); fail(); }
+        catch( Exception e ) { assertEquals("Undefined name 'i'",e.getMessage()); }
+    }
+    @Test
+    public void testFor5() {
+        CodeGen code = new CodeGen("""
+for(;;arg++;) {}
+""");
+        try { code.parse().opto(); fail(); }
+        catch( Exception e ) { assertEquals("Syntax error, expected Unexpected code after expression: ;",e.getMessage()); }
+    }
+
+
+
+    // ---------------------------------------------------------------
+    @Test
+    public void testForward0() {
+        CodeGen code = new CodeGen("""
+struct A{
+    B? f1;
+    B? f2;
+};
+return new A;
+""");
+        code.parse().opto();
+        assertEquals("return A;", code.print());
+        assertEquals("A{f1=null,f2=null}", Eval2.eval(code,0));
+    }
+
+    @Test
+    public void testForward1() {
+        CodeGen code = new CodeGen("""
+struct A{
+    B?[]? nil_array_of_b;
+    B?[]  not_array_of_b = new B?[0];
+};
+return new A.not_array_of_b;
+""");
+        code.parse().opto();
+        assertEquals("return (const)[*B?];", code.print());
+        assertEquals("*B?[]", Eval2.eval(code,0));
+    }
+
+    // ---------------------------------------------------------------
+    @Test
+    public void testLinkedList2() {
+        CodeGen code = new CodeGen("""
+struct LLI { LLI? next; int i; };
+LLI? !head = null;
+while( arg-- )
+    head = new LLI { next=head; i=arg; };
+int sum=0;
+var ptr = head; // A read-only ptr, to be assigned from read-only next fields
+for( ; ptr; ptr = ptr.next )
+    sum += ptr.i;
+return sum;
+""");
+        code.parse().opto();
+        assertEquals("return Phi(Loop,0,(Phi_sum+.i));", code.print());
+        assertEquals("45", Eval2.eval(code, 10));
+    }
+
+    @Test
+    public void sieveOfEratosthenes() {
+        CodeGen code = new CodeGen(
+"""
+var ary = new bool[arg], primes = new int[arg];
+var nprimes=0, p=0;
+// Find primes while p^2 < arg
+for( p=2; p*p < arg; p++ ) {
+    // skip marked non-primes
+    while( ary[p] ) p++;
+    // p is now a prime
+    primes[nprimes++] = p;
+    // Mark out the rest non-primes
+    for( int i = p + p; i < ary#; i += p )
+        ary[i] = true;
+}
+// Now just collect the remaining primes, no more marking
+for( ; p < arg; p++ )
+    if( !ary[p] )
+        primes[nprimes++] = p;
+// Copy/shrink the result array
+var !rez = new int[nprimes];
+for( int j=0; j<nprimes; j++ )
+    rez[j] = primes[j];
+return rez;
+""");
+        code.parse().opto().typeCheck().GCM();
+        assertEquals("return [int];", code.print());
+        assertEquals("int[ 2,3,5,7,11,13,17,19]",Eval2.eval(code, 20));
+    }
+
+}
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/Chapter18Test.java b/chapter22/src/test/java/com/seaofnodes/simple/Chapter18Test.java
new file mode 100644
index 00000000..c0e28412
--- /dev/null
+++ b/chapter22/src/test/java/com/seaofnodes/simple/Chapter18Test.java
@@ -0,0 +1,370 @@
+package com.seaofnodes.simple;
+
+import com.seaofnodes.simple.codegen.CodeGen.Phase;
+import com.seaofnodes.simple.codegen.CodeGen;
+import org.junit.Ignore;
+import org.junit.Test;
+import static org.junit.Assert.*;
+import static org.junit.Assert.fail;
+
+public class Chapter18Test {
+
+    @Test
+    public void testJig() {
+        CodeGen code = new CodeGen(
+"""
+return 0;
+""");
+        code.driver(Phase.LocalSched);
+        assertEquals("return 0;", code._stop.toString());
+        assertEquals("0", Eval2.eval(code,  2));
+    }
+
+    @Test
+    public void testPhiParalleAssign() {
+        CodeGen code = new CodeGen(
+"""
+int a = 1;
+int b = 2;
+while(arg--) {
+  int t = a;
+  a = b;
+  b = t;
+}
+return a;
+""");
+        code.parse().opto().typeCheck().GCM();
+        assertEquals("return Phi(Loop,1,Phi(Loop,2,Phi_a));", code._stop.toString());
+        assertEquals("1", Eval2.eval(code,  0));
+        assertEquals("2", Eval2.eval(code,  1));
+        assertEquals("1", Eval2.eval(code,  2));
+        assertEquals("2", Eval2.eval(code,  3));
+    }
+
+
+    // ---------------------------------------------------------------
+    @Test
+    public void testType0() {
+        CodeGen code = new CodeGen(
+"""
+{int -> int}? x2 = null; // null function ptr
+return x2;
+""");
+        code.parse().opto();
+        assertEquals("return null;", code._stop.toString());
+        assertEquals("null", Eval2.eval(code, 0 ) );
+    }
+
+    @Test
+    public void testFcn0() {
+        CodeGen code = new CodeGen(
+"""
+{int -> int}? sq = { int x ->
+    x*x;
+};
+""");
+        code.parse().opto();
+        assertEquals("return (Parm_x(sq,int)*x);", code._stop.toString());
+        //assertEquals("{ int -> int #1}", Eval2.eval(code, 3));
+    }
+
+    @Test
+    public void testFcn1() {
+        CodeGen code = new CodeGen(
+"""
+var sq = { int x ->
+    x*x;
+};
+return sq(arg)+sq(3);
+""");
+        code.driver(Phase.LocalSched);
+        assertEquals("Stop[ return (#2+#2); return (Parm_x(sq,int)*x); ]", code._stop.toString());
+        assertEquals("13", Eval2.eval(code, 2));
+    }
+
+    // Function scope test
+    @Test
+    public void testFcn2() {
+        CodeGen code = new CodeGen(
+"""
+int cnt=1;
+return { -> cnt; };
+""");
+        try { code.parse().opto(); fail(); }
+        catch( Exception e ) { assertEquals("Variable 'cnt' is out of function scope and must be a final constant",e.getMessage()); }
+    }
+
+    // Function scope test
+    @Test
+    public void testFcn3() {
+        CodeGen code = new CodeGen(
+"""
+val cnt=2;
+return { -> cnt; }();
+""");
+        code.parse().opto();
+        assertEquals("return 2;", code._stop.toString());
+        assertEquals("2", Eval2.eval(code, 0));
+    }
+
+    // Function variables
+    @Test
+    public void testFcn4() {
+        CodeGen code = new CodeGen(
+"""
+var fcn = arg ? { int x -> x*x; } : { int x -> x+x; };
+return fcn(3);
+""");
+        code.parse().opto();
+        assertEquals("Stop[ return #2; return (Parm_x($fun1,int,3)*x); return (Parm_x($fun2,int,3)<<1); ]", code._stop.toString());
+        assertEquals("6", Eval2.eval(code, 0));
+        assertEquals("9", Eval2.eval(code, 1));
+    }
+
+    // Recursive factorial test
+    @Test
+    public void testFcn5() {
+        CodeGen code = new CodeGen("val fact = { int x -> x <= 1 ? 1 : x*fact(x-1); }; return fact(arg);");
+        code.parse().opto().typeCheck();
+        assertEquals("Stop[ return #2; return Phi(Region,1,(Parm_x(fact,int,arg,(x-1))*#2)); ]", code._stop.toString());
+        assertEquals( "1", Eval2.eval(code, 0));
+        assertEquals( "1", Eval2.eval(code, 1));
+        assertEquals( "2", Eval2.eval(code, 2));
+        assertEquals( "6", Eval2.eval(code, 3));
+        assertEquals("24", Eval2.eval(code, 4));
+    }
+
+    @Test
+    public void testFcn6() {
+        CodeGen code = new CodeGen(
+"""
+struct S { int i; };
+val newS = { int x -> return new S { i=x; }; };
+return newS(1).i;
+""");
+        code.parse().opto().typeCheck().GCM();
+        assertEquals("return 1;", code._stop.toString());
+        assertEquals("1", Eval2.eval(code,  0));
+    }
+
+    // Double forward reference
+    @Test
+    public void testFcn7() {
+        CodeGen code = new CodeGen(
+"""
+if( arg ? f : g ) return 1;
+val f = {->1;};
+val g = {->2;};
+return 2;
+""");
+        code.parse().opto().typeCheck().GCM();
+        assertEquals("Stop[ return 1; return 1; return 2; ]", code._stop.toString());
+        assertEquals("1", Eval2.eval(code,  0));
+    }
+
+    @Test
+    public void testFcn8() {
+        CodeGen code = new CodeGen(
+"""
+{int -> int}? i2i = null;
+var id = {{int->int} f-> return f;};
+for(;;) {
+    if (i2i) return i2i(arg);
+    var x = {int i-> return i;};
+    arg = x(3);
+    i2i = id(x);
+}
+""");
+        code.driver(Phase.LocalSched);
+        assertEquals("Stop[ return #2; return Parm_i(x,int); ]", code._stop.toString());
+        assertEquals("3", Eval2.eval(code,  0));
+    }
+
+    @Test
+    public void testFcn9() {
+        CodeGen code = new CodeGen(
+"""
+{int -> int}? i2i = null;
+for(;;) {
+    if (i2i) return i2i(arg);
+    var x = {int i-> return i;};
+    arg = x(3);
+}
+""");
+        code.driver(Phase.LocalSched);
+        assertEquals("return Top;", code._stop.toString());
+        assertEquals("null", Eval2.eval(code,  0));
+    }
+
+
+    @Test
+    public void testFcn10() {
+        CodeGen code = new CodeGen(
+"""
+struct Person {
+  int age;
+};
+
+val fcn = { Person?[] ps, int x ->
+  val tmp = ps[x];
+  if( ps[x] )
+    ps[x].age++;
+};
+
+var ps = new Person?[2];
+ps[0] = new Person;
+ps[1] = new Person;
+fcn(ps,1);
+""");
+        code.driver(Phase.LocalSched);
+        assertEquals("return 0;", code._stop.toString());
+        assertEquals("0", Eval2.eval(code,  0));
+    }
+
+    // Function break
+    @Test
+    public void testErr1() {
+        CodeGen code = new CodeGen(
+"""
+for(;;) {
+    val f = { ->
+        break;
+    };
+    f();
+    return 2;
+}
+return 1;
+""");
+        try { code.parse().opto(); fail(); }
+        catch( Exception e ) { assertEquals("No active loop for a break or continue",e.getMessage()); }
+    }
+
+    // Calling and inlining a null function
+    @Test
+    public void testErr2() {
+        CodeGen code = new CodeGen(
+"""
+{int -> int}? !i2i = { int i -> return i; };
+for(;;) {
+    if (i2i(2) == arg) break;
+    i2i = null;
+}
+""");
+        try { code.parse().opto().typeCheck(); fail(); }
+        catch( Exception e ) { assertEquals("Might be null calling { int -> int #1}?",e.getMessage()); }
+    }
+
+
+    @Test
+    public void testErr3() {
+        CodeGen code = new CodeGen(
+"""
+val f = { int i, int j -> return i+j; };
+return f();
+""");
+        try { code.parse().opto().typeCheck(); fail(); }
+        catch( Exception e ) { assertEquals("Expecting 2 arguments, but found 0",e.getMessage()); }
+    }
+
+
+    @Test
+    public void testErr4() {
+        CodeGen code = new CodeGen(
+"""
+struct S {
+    {int} f = { -> x(); return 0; }; // Do not let fref x be a field
+};
+val x = { -> return 1; };
+S? s = null;
+for(;;) {
+    if (s) return s.x;
+}
+""");
+        try { code.parse().opto().typeCheck(); fail(); }
+        catch( Exception e ) { assertEquals("Accessing unknown field 'x' from '*S'",e.getMessage()); }
+    }
+
+    @Test
+    public void testErr5() {
+        CodeGen code = new CodeGen(
+"""
+val g = { ->
+    g();
+};
+return 0;
+""");
+        try { code.parse().opto().typeCheck(); fail(); }
+        catch( Exception e ) { assertEquals("No defined return type",e.getMessage()); }
+    }
+
+
+    // Mutual recursion.  Fails without SCCP to lift the recursive return types.
+    @Ignore @Test
+    public void testFcnMutRec() {
+        CodeGen code = new CodeGen(
+"""
+val is_even = { int x -> x ? is_odd (x-1) : true ; };
+val is_odd  = { int x -> x ? is_even(x-1) : false; };
+return is_even(arg);
+""");
+        code.parse().opto();
+        assertEquals("Stop[ return is_even( arg); return Phi(Region,Phi(Region,is_even( ((Parm_x(is_even,int,arg,Sub)-1)-1)),0),1); ]", code._stop.toString());
+        assertEquals("1", Eval2.eval(code, 0));
+        assertEquals("0", Eval2.eval(code, 1));
+        assertEquals("1", Eval2.eval(code, 2));
+        assertEquals("0", Eval2.eval(code, 3));
+    }
+
+    // Forward ref to 'x' means that
+    @Ignore @Test
+    public void testForwardRef1() {
+        CodeGen code = new CodeGen(
+"""
+struct S {
+    { int } f = { -> return x(); };
+};
+val x = { -> return 1; };
+S? s = null;
+for(;;) {
+    if (s) return s.f;
+}
+""");
+        code.parse().opto().typeCheck().GCM();
+        assertEquals("return 0;", code._stop.toString());
+        assertEquals("0", Eval2.eval(code,  0));
+    }
+
+    // Inline hidden called more than once
+    @Test
+    public void testInline() {
+        CodeGen code = new CodeGen(
+"""
+{int->int}?! i2i = {int i->return i;};
+{{int->int}->{int->int}}! f2f = {{int->int} f->return f;};
+val o = i2i;
+if (arg) i2i = null;
+if (i2i) return i2i(arg);
+return f2f(o)(1);
+""");
+        code.driver(Phase.LocalSched);
+        assertEquals("Stop[ return Phi(Region,#2,#2); return Parm_i(o,int); ]", code._stop.toString());
+        assertEquals("1", Eval2.eval(code,  2));
+    }
+
+    @Test
+    public void testOperField() {
+        CodeGen code = new CodeGen(
+"""
+struct Person {
+    int coffee_count;
+};
+Person !p = new Person;
+p.coffee_count += 1;
+return p.coffee_count;
+""");
+        code.driver(Phase.LocalSched);
+        assertEquals("return 1;", code._stop.toString());
+        assertEquals("1", Eval2.eval(code,  2));
+    }
+
+}
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/Chapter19Test.java b/chapter22/src/test/java/com/seaofnodes/simple/Chapter19Test.java
new file mode 100644
index 00000000..bce75c81
--- /dev/null
+++ b/chapter22/src/test/java/com/seaofnodes/simple/Chapter19Test.java
@@ -0,0 +1,331 @@
+package com.seaofnodes.simple;
+
+import com.seaofnodes.simple.codegen.CodeGen.Phase;
+import com.seaofnodes.simple.codegen.CodeGen;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import org.junit.Test;
+import static org.junit.Assert.*;
+
+public class Chapter19Test {
+
+    @Test
+    public void testJig() {
+        CodeGen code = new CodeGen("""
+return 0;
+""");
+        code.parse().opto().typeCheck();
+        assertEquals("return 0;", code._stop.toString());
+        assertEquals("0", Eval2.eval(code,  2));
+    }
+
+
+    @Test
+    public void testString() throws IOException {
+        String src = Files.readString(Path.of("src/test/java/com/seaofnodes/simple/progs/stringHash.smp"));
+        CodeGen code = new CodeGen(src).parse().opto().typeCheck().GCM().localSched();
+        assertEquals("Stop[ return Phi(Region,._hashCode,Phi(Region,123456789,Phi(Loop,0,(.[]+((Phi_hash<<5)-Phi_hash))))); return Phi(Region,1,0,0,1); ]", code._stop.toString());
+        //assertEquals("-4898613127354160978", Eval2.eval(code,  2));
+    }
+
+    @Test
+    public void testBasic0() {
+        CodeGen code = new CodeGen("return 0;").driver(Phase.LocalSched,"x86_64_v2", "SystemV");
+        assertEquals("return 0;", code._stop.toString());
+    }
+
+    @Test
+    public void testBasic1() {
+        CodeGen code = new CodeGen("return arg+1;").driver(Phase.LocalSched,"x86_64_v2", "SystemV");
+        assertEquals("return (inc,arg);", code._stop.toString());
+    }
+
+    @Test
+    public void testBasic2() {
+        CodeGen code = new CodeGen("return -17;").driver(Phase.LocalSched,"x86_64_v2", "SystemV");
+        assertEquals("return -17;", code._stop.toString());
+    }
+
+
+    @Test
+    public void testBasic3() {
+        CodeGen code = new CodeGen("return arg==1;").driver(Phase.LocalSched,"x86_64_v2", "SystemV");
+        assertEquals("return (set==,(cmp,arg));", code._stop.toString());
+    }
+
+    @Test
+    public void testBasic4() {
+        CodeGen code = new CodeGen("return arg<<1;").driver(Phase.LocalSched,"x86_64_v2", "SystemV");
+        assertEquals("return (shli,arg);", code._stop.toString());
+    }
+
+    @Test
+    public void testBasic5() {
+        CodeGen code = new CodeGen("return arg >> 1;").driver(Phase.LocalSched,"x86_64_v2", "SystemV");
+        assertEquals("return (sari,arg);", code._stop.toString());
+    }
+
+    @Test
+    public void testBasic6() {
+        CodeGen code = new CodeGen("return arg >>> 1;").driver(Phase.LocalSched,"x86_64_v2", "SystemV");
+        assertEquals("return (shri,arg);", code._stop.toString());
+    }
+
+    @Test
+    public void testBasic7() {
+        CodeGen code = new CodeGen("return arg / 2;").driver(Phase.LocalSched,"x86_64_v2", "SystemV");
+        assertEquals("return (div,arg,2);", code._stop.toString());
+    }
+
+    @Test
+    public void testBasic8() {
+        CodeGen code = new CodeGen("return arg * 6;").driver(Phase.LocalSched,"x86_64_v2", "SystemV");
+        assertEquals("return (muli,arg);", code._stop.toString());
+    }
+
+    @Test
+    public void testBasic9() {
+        CodeGen code = new CodeGen("return arg & 2;").driver(Phase.LocalSched,"x86_64_v2", "SystemV");
+        assertEquals("return (andi,arg);", code._stop.toString());
+    }
+
+    @Test
+    public void testBasic10() {
+        CodeGen code = new CodeGen("return arg | 2;").driver(Phase.LocalSched,"x86_64_v2", "SystemV");
+        assertEquals("return (ori,arg);", code._stop.toString());
+    }
+
+    @Test
+    public void testBasic11() {
+        CodeGen code = new CodeGen("return arg ^ 2;").driver(Phase.LocalSched,"x86_64_v2", "SystemV");
+        assertEquals("return (xori,arg);", code._stop.toString());
+    }
+
+    @Test
+    public void testBasic12() {
+        CodeGen code = new CodeGen("return arg + 2.0;").driver(Phase.LocalSched,"x86_64_v2", "SystemV");
+        assertEquals("return (addf,(cvtf,arg),2.0f);", code._stop.toString());
+    }
+
+    @Test
+    public void testBasic13() {
+        CodeGen code = new CodeGen("return arg - 2.0;").driver(Phase.LocalSched,"x86_64_v2", "SystemV");
+        assertEquals("return (subf,(cvtf,arg),2.0f);", code._stop.toString());
+    }
+
+    @Test
+    public void testBasic14() {
+        CodeGen code = new CodeGen("return arg * 2.0;").driver(Phase.LocalSched,"x86_64_v2", "SystemV");
+        assertEquals("return (mulf,(cvtf,arg),2.0f);", code._stop.toString());
+    }
+
+    @Test
+    public void testBasic15() {
+        CodeGen code = new CodeGen("return arg / 2.0;").driver(Phase.LocalSched,"x86_64_v2", "SystemV");
+        assertEquals("return (mulf,(cvtf,arg),0.5f);", code._stop.toString());
+    }
+
+    @Test
+    public void testBasic16() {
+        CodeGen code = new CodeGen(
+"""
+int arg1 =  arg + 1;
+return arg1 / arg;""");
+        code.driver(Phase.LocalSched,"x86_64_v2", "SystemV");
+        assertEquals("return (div,(inc,arg),arg);", code._stop.toString());
+    }
+
+    @Test
+    public void testBasic17() {
+        CodeGen code = new CodeGen(
+"""
+int arg1 =  arg + 1;
+return arg1 * arg;
+""");
+        code.driver(Phase.LocalSched,"x86_64_v2", "SystemV");
+        assertEquals("return (mul,(inc,arg),arg);", code._stop.toString());
+    }
+
+    @Test
+    public void testToFloat() {
+        CodeGen code = new CodeGen("""
+int a = arg;
+return a + 2.0;
+"""
+        ).driver(Phase.LocalSched,"x86_64_v2", "SystemV");
+        assertEquals("return (addf,(cvtf,arg),2.0f);", code._stop.toString());
+    }
+
+    @Test
+    public void testIfStmt() {
+        CodeGen code = new CodeGen(
+"""
+int a = 1;
+if (arg == 1)
+    a = arg+2;
+else {
+    a = arg-3;
+}
+return a;""");
+        code.driver(Phase.LocalSched,"x86_64_v2", "SystemV");
+        assertEquals("return Phi(Region,(addi,arg),(addi,arg));", code.print());
+    }
+
+    @Test
+    public void testIfMerge2() {
+        CodeGen code = new CodeGen(
+"""
+int a=arg+1;
+int b=arg+2;
+if( arg==1 )
+    b=b+a;
+else
+    a=b+1;
+return a+b;""");
+        code.driver(Phase.LocalSched,"x86_64_v2", "SystemV");
+        assertEquals("return (add,(add,Phi(Region,(shli,arg),arg),arg),Phi(Region,4,5));", code.print());
+    }
+
+    @Test
+    public void testLoop() {
+        CodeGen code = new CodeGen(
+"""
+int sum=0;
+for( int i=0; i<arg; i++ )
+    sum += i;
+return sum;""");
+        code.driver(Phase.LocalSched,"x86_64_v2", "SystemV");
+        assertEquals("return Phi(Loop,0,(add,Phi_sum,Phi(Loop,0,(inc,Phi_i))));", code.print());
+    }
+
+    @Test
+    public void testAlloc1() {
+        CodeGen code = new CodeGen(
+"""
+struct S { int a; S? c; };
+return new S;""");
+        code.driver(Phase.LocalSched,"x86_64_v2", "SystemV");
+        assertEquals("return S;", code.print());
+    }
+
+    @Test
+    public void testLea1() {
+        CodeGen code = new CodeGen("int x = arg/3; return arg+x+7;");
+        code.driver(Phase.LocalSched,"x86_64_v2", "SystemV");
+        assertEquals("return (lea,arg,(div,arg,3));", code.print());
+    }
+
+    @Test
+    public void testLea2() {
+        CodeGen code = new CodeGen("int x = arg/3; return arg+x*4+7;");
+        code.driver(Phase.LocalSched,"x86_64_v2", "SystemV");
+        assertEquals("return (lea,arg,(div,arg,3));", code.print());
+    }
+
+    @Test
+    public void testLea3() {
+        CodeGen code = new CodeGen("int x = arg/3; return x*4+arg;");
+        code.driver(Phase.LocalSched,"x86_64_v2", "SystemV");
+        assertEquals("return (lea,arg,(div,arg,3));", code.print());
+    }
+
+    @Test
+    public void testAlloc2() {
+        CodeGen code = new CodeGen("int[] !xs = new int[3]; xs[arg]=1; return xs[arg&1];");
+        code.driver(Phase.LocalSched,"x86_64_v2", "SystemV");
+        assertEquals("return .[];", code.print());
+    }
+
+    @Test
+    public void testAlloc3() {
+        CodeGen code = new CodeGen("int[] !xs = new int[3]; xs[arg]=1; return xs[arg&1]+3;");
+        code.driver(Phase.LocalSched,"x86_64_v2", "SystemV");
+        assertEquals("return .[];", code.print());
+    }
+
+    @Test
+    public void testArray1() {
+        CodeGen code = new CodeGen(
+"""
+int[] !ary = new int[arg];
+// Fill [0,1,2,3,4,...]
+for( int i=0; i<ary#; i++ )
+    ary[i] = i;
+// Fill [0,1,3,6,10,...]
+for( int i=0; i<ary#-1; i++ )
+    ary[i+1] += ary[i];
+return ary[1] * 1000 + ary[3]; // 1 * 1000 + 6
+""");
+        code.driver(Phase.LocalSched,"x86_64_v2", "SystemV");
+        assertEquals("return .[];", code.print());
+    }
+
+    @Test
+    public void testArray2() {
+        CodeGen code = new CodeGen(
+"""
+flt[] !A = new flt[arg], !B = new flt[arg];
+// Fill [0,1,2,3,4,...]
+for( int i=0; i<A#; i++ )
+    A[i] = i;
+for( int i=0; i<A#; i++ )
+    B[i] += A[i];
+""");
+        code.driver(Phase.LocalSched,"x86_64_v2", "SystemV");
+        assertEquals("return 0;", code.print());
+    }
+
+    @Test
+    public void testArray3() {
+        CodeGen code = new CodeGen(
+"""
+byte[] !A = new byte[arg];
+for( int i=0; i<A#; i++ )
+    A[i]++;
+return A[1];
+""");
+        code.driver(Phase.LocalSched,"x86_64_v2", "SystemV");
+        assertEquals("return .[];", code.print());
+    }
+
+    @Test
+    public void testNewton() throws IOException {
+        String src = Files.readString(Path.of("src/test/java/com/seaofnodes/simple/progs/newtonFloat.smp"))
+            + "flt farg = arg;  return test_sqrt(farg);";
+        CodeGen code = new CodeGen(src).driver(Phase.LocalSched,"x86_64_v2", "SystemV");
+        assertEquals("return Phi(Loop,(cvtf,arg),(mulf,(addf,(divf,cvtf,Phi_guess),Phi_guess),0.5f));", code.print());
+    };
+
+
+    @Test
+    public void sieveOfEratosthenes() throws IOException {
+        String src = Files.readString(Path.of("src/test/java/com/seaofnodes/simple/progs/sieve.smp"));
+        CodeGen code = new CodeGen(src).driver(Phase.LocalSched,"x86_64_v2", "SystemV");
+        assertEquals("return [u32];", code.print());
+        //assertEquals("u32[ 2,3,5,7,11,13,17,19]",Eval2.eval(code, 20));
+    }
+
+
+    @Test
+    public void testFcn1() {
+        CodeGen code = new CodeGen(
+"""
+val fcn = arg ? { int x -> x*x; } : { int x -> x+x; };
+return fcn(2)*10 + fcn(3);
+""");
+        code.driver(Phase.LocalSched,"x86_64_v2", "SystemV");
+        assertEquals("Stop[ return (add,#2,(muli,#2)); return (mul,Parm_x($fun1,int),x); return (shli,Parm_x($fun2,int)); ]", code.print());
+    }
+
+    @Test
+    public void testFcn2() {
+        CodeGen code = new CodeGen(
+"""
+val sq = { int x -> x*x; };
+return sq(arg) + sq(3);
+""");
+        code.driver(Phase.LocalSched,"x86_64_v2", "SystemV");
+        assertEquals("Stop[ return (add,#2,#2); return (mul,Parm_x(sq,int),x); ]", code.print());
+    }
+}
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/Chapter20Test.java b/chapter22/src/test/java/com/seaofnodes/simple/Chapter20Test.java
new file mode 100644
index 00000000..83902b6d
--- /dev/null
+++ b/chapter22/src/test/java/com/seaofnodes/simple/Chapter20Test.java
@@ -0,0 +1,151 @@
+package com.seaofnodes.simple;
+
+import com.seaofnodes.simple.codegen.CodeGen;
+import com.seaofnodes.simple.print.ASMPrinter;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import org.junit.Assert;
+import org.junit.Ignore;
+import org.junit.Test;
+import static org.junit.Assert.*;
+
+public class Chapter20Test {
+
+    @Test
+    public void testJig() {
+        CodeGen code = new CodeGen("return 0;");
+        code.parse().opto().typeCheck();
+        assertEquals("return 0;", code._stop.toString());
+        assertEquals("0", Eval2.eval(code,  2));
+    }
+
+    static void testCPU( String src, String cpu, String os, int spills, String stop ) {
+        CodeGen code = new CodeGen(src);
+        code.driver(CodeGen.Phase.RegAlloc,cpu,os);
+        int delta = spills>>3;
+        if( delta==0 ) delta = 1;
+        if( spills != -1 )
+            assertEquals("Expect spills:",spills,code._regAlloc._spillScaled,delta);
+        if( stop != null )
+            assertEquals(stop, code._stop.toString());
+    }
+
+    private static void testAllCPUs( String src, int spills, String stop ) {
+        testCPU(src,"x86_64_v2", "SystemV",spills,stop);
+        testCPU(src,"riscv"    , "SystemV",spills,stop);
+        testCPU(src,"arm"      , "SystemV",spills,stop);
+    }
+
+    @Test public void testAlloc0() {
+        testCPU("return new u8[arg];","x86_64_v2", "SystemV",3,"return [u8];");
+        testCPU("return new u8[arg];","riscv"    , "SystemV",5,"return [u8];");
+        testCPU("return new u8[arg];","arm"      , "SystemV",5,"return [u8];");
+    }
+
+    @Test public void testBasic1() {
+        String src = "return arg | 2;";
+        testCPU(src,"x86_64_v2", "SystemV",1,"return (ori,mov(arg));");
+        testCPU(src,"riscv"    , "SystemV",0,"return ( arg | #2 );");
+        testCPU(src,"arm"      , "SystemV",0,"return (ori,arg);");
+    }
+
+    @Test
+    public void testNewtonInteger() {
+        String src =
+"""
+// Newtons approximation to the square root
+val sqrt = { int x ->
+    int guess = x;
+    while( 1 ) {
+        int next = (x/guess + guess)/2;
+        if( next == guess ) return guess;
+        guess = next;
+    }
+};
+return sqrt(arg) + sqrt(arg+2);
+""";
+        testCPU(src,"x86_64_v2", "Win64"  ,23,null);
+        testCPU(src,"riscv"    , "SystemV",19,null);
+        testCPU(src,"arm"      , "SystemV",19,null);
+    }
+
+    @Test
+    public void testNewtonFloat() throws IOException {
+        String src = Files.readString(Path.of("src/test/java/com/seaofnodes/simple/progs/newtonFloat.smp"))
+            + "flt farg = arg; return test_sqrt(farg) + test_sqrt(farg+2.0);";
+        testCPU(src,"x86_64_v2", "SystemV",39,null);
+        testCPU(src,"riscv"    , "SystemV",17,null);
+        testCPU(src,"arm"      , "SystemV",18,null);
+    }
+
+    @Test
+    public void testAlloc2() {
+        String src = "int[] !xs = new int[3]; xs[arg]=1; return xs[arg&1];";
+        testCPU(src,"x86_64_v2", "SystemV",-1,"return .[];");
+        testCPU(src,"riscv"    , "SystemV", 6,"return .[];");
+        testCPU(src,"arm"      , "SystemV", 4,"return .[];");
+    }
+
+
+
+    @Test
+    public void testArray1() throws IOException {
+        String src = Files.readString(Path.of("src/test/java/com/seaofnodes/simple/progs/array1.smp"));
+        testCPU(src,"x86_64_v2", "SystemV",-1,"return .[];");
+        testCPU(src,"riscv"    , "SystemV", 8,"return (add,.[],(mul,.[],1000));");
+        testCPU(src,"arm"      , "SystemV", 5,"return (add,.[],(mul,.[],1000));");
+    }
+
+
+    @Test
+    public void testString() throws IOException {
+        String src = Files.readString(Path.of("src/test/java/com/seaofnodes/simple/progs/stringHash.smp"));
+        testCPU(src,"x86_64_v2", "SystemV", 9,null);
+        testCPU(src,"riscv"    , "SystemV", 5,null);
+        testCPU(src,"arm"      , "SystemV", 6,null);
+    }
+
+    @Test
+    public void testCast() {
+        String src = "struct Bar { int x; }; var b = arg ? new Bar;  return b ? b.x++ + b.x++ : -1;";
+        testCPU(src,"x86_64_v2", "SystemV",2,null);
+        testCPU(src,"riscv"    , "SystemV",2,null);
+        testCPU(src,"arm"      , "SystemV",2,null);
+    }
+
+    @Test
+    public void testFltArg() {
+        String src = "return {int i, flt f, int j->return i+f+j;};";
+        testAllCPUs(src,0,null);
+    }
+
+    @Test
+    public void testFlags1() {
+        String src = """
+bool b1 = arg == 1;
+bool b2 = arg == 2;
+if (b2) if (b1) return 1;
+if (b1) return 2;
+return 0;
+""";
+        testCPU(src,"x86_64_v2", "SystemV",0,"return Phi(Region,1,2,0);");
+        testCPU(src,"riscv"    , "SystemV",0,"return Phi(Region,1,2,0);");
+        testCPU(src,"arm"      , "SystemV",0,"return Phi(Region,1,2,0);");
+    }
+
+    @Test
+    public void testFlags2() {
+        String src = """
+bool b1 = arg == 1;
+while (arg > 0) {
+    arg--;
+    if (b1) arg--;
+}
+return arg;
+""";
+        testCPU(src,"x86_64_v2", "SystemV",3,null);
+        testCPU(src,"riscv"    , "SystemV",2,null);
+        testCPU(src,"arm"      , "SystemV",2,null);
+    }
+}
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/Chapter21Test.java b/chapter22/src/test/java/com/seaofnodes/simple/Chapter21Test.java
new file mode 100644
index 00000000..1857367b
--- /dev/null
+++ b/chapter22/src/test/java/com/seaofnodes/simple/Chapter21Test.java
@@ -0,0 +1,259 @@
+package com.seaofnodes.simple;
+
+import com.seaofnodes.simple.codegen.CodeGen;
+import com.seaofnodes.simple.node.cpus.arm.arm;
+import com.seaofnodes.simple.node.cpus.riscv.riscv;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import org.junit.Ignore;
+import org.junit.Test;
+import static org.junit.Assert.*;
+
+public class Chapter21Test {
+
+    @Test
+    public void testJig() throws IOException {
+        String src = Files.readString(Path.of("src/test/java/com/seaofnodes/simple/progs/jig.smp"));
+        testCPU(src,"x86_64_v2", "Win64"  ,-1,null);
+        testCPU(src,"riscv"    , "SystemV",-1,null);
+        testCPU(src,"arm"      , "SystemV",-1,null);
+    }
+
+    static void testCPU( String src, String cpu, String os, int spills, String stop ) {
+        CodeGen code = new CodeGen(src).driver(CodeGen.Phase.Encoding,cpu,os);
+        int delta = spills>>3;
+        if( delta==0 ) delta = 1;
+        if( spills != -1 )
+            assertEquals("Expect spills:",spills,code._regAlloc._spillScaled,delta);
+        if( stop != null )
+            assertEquals(stop, code._stop.toString());
+    }
+
+
+    @Test public void testBasic1() {
+        String src = "return arg | 2;";
+        testCPU(src,"x86_64_v2", "SystemV",1,"return (ori,mov(arg));");
+        testCPU(src,"riscv"    , "SystemV",0,"return ( arg | #2 );");
+        testCPU(src,"arm"      , "SystemV",0,"return (ori,arg);");
+    }
+
+    @Test public void testInfinite() {
+        String src = "struct S { int i; }; S !s = new S; while(1) s.i++;";
+        testCPU(src,"x86_64_v2", "SystemV",0,"return Top;");
+        testCPU(src,"riscv"    , "SystemV",2,"return Top;");
+        testCPU(src,"arm"      , "SystemV",2,"return Top;");
+    }
+
+    @Test
+    public void testArray1() throws IOException {
+        String src = Files.readString(Path.of("src/test/java/com/seaofnodes/simple/progs/array1.smp"));
+        testCPU(src,"x86_64_v2", "SystemV",-1,"return .[];");
+        testCPU(src,"riscv"    , "SystemV", 7,"return (add,.[],(mul,.[],1000));");
+        testCPU(src,"arm"      , "SystemV", 5,"return (add,.[],(mul,.[],1000));");
+    }
+
+    @Test
+    public void testAntiDeps1() throws IOException {
+        String src = Files.readString(Path.of("src/test/java/com/seaofnodes/simple/progs/antiDep1.smp"));
+        testCPU(src,"x86_64_v2", "SystemV", 7,"return mov(mov(S));");
+        testCPU(src,"riscv"    , "SystemV",10,"return mov(mov(S));");
+        testCPU(src,"arm"      , "SystemV",10,"return mov(mov(S));");
+    }
+
+    @Test
+    public void testString() throws IOException {
+        String src = Files.readString(Path.of("src/test/java/com/seaofnodes/simple/progs/stringHash.smp"));
+        testCPU(src,"x86_64_v2", "SystemV", 9,null);
+        testCPU(src,"riscv"    , "SystemV", 5,null);
+        testCPU(src,"arm"      , "SystemV", 6,null);
+    }
+
+    @Test public void testStringExport() throws IOException {
+        TestC.run("stringHash", 9);
+    }
+
+    @Test public void testLoop2() throws IOException {
+        String src = Files.readString(Path.of("src/test/java/com/seaofnodes/simple/progs/loop2.smp"));
+        testCPU(src,"x86_64_v2", "Win64"  ,0,"return (inc,Phi(Loop,0,inc));");
+        testCPU(src,"riscv"    , "SystemV",0,"return ( Phi(Loop,0,addi) + #1 );");
+        testCPU(src,"arm"      , "SystemV",0,"return (inc,Phi(Loop,0,inc));");
+    }
+
+    @Test public void testNewtonExport() throws IOException {
+        String result = """
+0  0.000000   (0)
+1  1.000000   (0)
+2  1.414214   (2.22045e-16)
+3  1.732051   (0)
+4  2.000000   (0)
+5  2.236068   (0)
+6  2.449490   (0)
+7  2.645751   (0)
+8  2.828427   (4.44089e-16)
+9  3.000000   (0)
+""";
+        TestC.run("newtonFloat",result,34);
+
+        EvalRisc5 R5 = TestRisc5.build("newtonFloat", 0, 10, false);
+        R5.fregs[riscv.FA0 - riscv.F_OFFSET] = 3.0;
+        int trap_r5 = R5.step(1000);
+        assertEquals(0,trap_r5);
+        // Return register A0 holds fib(8)==55
+        assertEquals(1.732051,R5.fregs[riscv.FA0 - riscv.F_OFFSET], 0.00001);
+
+        // arm
+        EvalArm64 A5 = TestArm64.build("newtonFloat", 0, 10, false);
+        A5.fregs[arm.D0 - arm.D_OFFSET] = 3.0;
+        int trap_arm = A5.step(1000);
+        assertEquals(0,trap_arm);
+        assertEquals(1.732051, A5.fregs[arm.D0 - arm.D_OFFSET], 0.00001);
+    }
+
+
+    @Test public void testSieve() throws IOException {
+        // The primes
+        int[] primes = new int[] { 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, };
+        SB sb = new SB().p(primes.length).p("[");
+        for( int prime : primes )
+            sb.p(prime).p(", ");
+        String sprimes = sb.p("]").toString();
+
+        // Compile, link against native C; expect the above string of primes to be printed out by C
+        TestC.run("sieve",sprimes, 257);
+
+        // Evaluate on RISC5 emulator; expect return of an array of primes in
+        // the simulated heap.
+        EvalRisc5 R5 = TestRisc5.build("sieve", 100, 160, false);
+        int trap = R5.step(10000);
+        assertEquals(0,trap);
+        // Return register A0 holds sieve(100)
+        int ary = (int)R5.regs[riscv.A0];
+        // Memory layout starting at ary(length,pad, prime1, primt2, prime3, prime4)
+        assertEquals(primes.length, R5.ld4s(ary));
+        for( int i=0; i<primes.length; i++ )
+            assertEquals(primes[i], R5.ld4s(ary + 4 + i*4));
+
+        //// Evaluate on ARM5 emulator; expect return of an array of primes in the simulated heap.
+        //EvalArm64 A5 = TestArm64.build("sieve", 100, 160, false);
+        //int trap_arm = A5.step(10000);
+        //assertEquals(0, trap_arm);
+        //int ary_arm = (int)A5.regs[arm.X0];
+        //// Memory layout starting at ary(length,pad, prime1, primt2, prime3, prime4)
+        //assertEquals(primes.length, A5.ld4s(ary_arm));
+        //for(int i = 0; i<primes.length; i++)
+        //    assertEquals(primes[i], A5.ld4s(ary_arm + 4 + i * 4));
+    }
+
+    @Test public void testFibExport() throws IOException {
+        String fib = "[1, 1, 2, 3, 5, 8, 13, 21, 34, 55]";
+        TestC.run("fib", fib, 24);
+
+        EvalRisc5 R5 = TestRisc5.build("fib", 9, 16, false);
+        int trap = R5.step(100);
+        assertEquals(0,trap);
+        // Return register A0 holds fib(8)==55
+        assertEquals(55,R5.regs[riscv.A0]);
+
+        // arm
+        EvalArm64 A5 = TestArm64.build("fib", 9, 16, false);
+        int trap_arm = A5.step(100);
+        assertEquals(0,trap_arm);
+        // Return register X0 holds fib(8)==55
+        assertEquals(55, A5.regs[arm.X0]);
+    }
+
+    @Test public void testPerson() throws IOException {
+        String person = "6\n";
+        TestC.run("person", person, 0);
+
+        // Memory layout starting at PS:
+        int ps = 1<<16;         // Person array pointer
+        // Person[3] = { len,pad,P0,P1,P2 }; // sizeof = 4*8
+        // P0 = { age } // sizeof=8
+        int p0 = ps+4*8+0*8;
+        // P1 = { age } // sizeof=8
+        int p1 = ps+4*8+1*8;
+        // P2 = { age } // sizeof=8
+        int p2 = ps+4*8+2*8;
+        EvalRisc5 R5 = TestRisc5.build("person", ps, 0, false);
+        R5.regs[riscv.A1] = 1;  // Index 1
+        R5.st4(ps,3);           // Length
+        R5.st8(ps+1*8,p0);
+        R5.st8(ps+2*8,p1);
+        R5.st8(ps+3*8,p2);
+        R5.st8(p0, 5); // age= 5
+        R5.st8(p1,17); // age=17
+        R5.st8(p2,60); // age=60
+
+        int trap = R5.step(100);
+        assertEquals(0,trap);
+        assertEquals( 5+0,R5.ld8(p0));
+        assertEquals(17+1,R5.ld8(p1));
+        assertEquals(60+0,R5.ld8(p2));
+    }
+
+    @Test public void testArgCount() throws IOException {
+        // Test passes more args than registers in Sys5, which is far far more
+        // than what Win64 allows - so Win64 gets a lot more spills here.
+        String arg_count = "191.000000\n";
+        TestC.run("arg_count", arg_count,
+                  TestC.CALL_CONVENTION.equals("Win64") ? 42 : 15);
+
+
+        EvalRisc5 R5 = TestRisc5.build("no_stack_arg_count", 0, 0, false);
+
+        // Todo: handle stack(imaginary stack in emulator)
+        // pass in float arguments
+        R5.fregs[riscv.FA0 - riscv.F_OFFSET] = 1.1;
+        R5.fregs[riscv.FA1 - riscv.F_OFFSET] = 1.1;
+        R5.fregs[riscv.FA2 - riscv.F_OFFSET] = 1.1;
+        R5.fregs[riscv.FA3 - riscv.F_OFFSET] = 1.1;
+        R5.fregs[riscv.FA4 - riscv.F_OFFSET] = 1.1;
+        R5.fregs[riscv.FA5 - riscv.F_OFFSET] = 1.1;
+        R5.fregs[riscv.FA6 - riscv.F_OFFSET] = 1.1;
+        R5.fregs[riscv.FA7 - riscv.F_OFFSET] = 1.1;
+
+        // a0 is passed in arg
+        R5.regs[riscv.A1] = 2;
+        R5.regs[riscv.A2] = 2;
+        R5.regs[riscv.A3] = 2;
+        R5.regs[riscv.A4] = 2;
+        R5.regs[riscv.A5] = 2;
+        R5.regs[riscv.A6] = 2;
+        R5.regs[riscv.A7] = 2;
+
+        int trap = R5.step(100);
+        assertEquals(0,trap);
+
+        double result = R5.fregs[riscv.FA0 - riscv.F_OFFSET];
+
+        assertEquals(22.8, result, 0.00001);
+
+        // arm
+        EvalArm64 A5 = TestArm64.build("no_stack_arg_count", 0, 0, false);
+
+        A5.fregs[arm.D0 - arm.D_OFFSET] = 1.1;
+        A5.fregs[arm.D1 - arm.D_OFFSET] = 1.1;
+        A5.fregs[arm.D2 - arm.D_OFFSET] = 1.1;
+        A5.fregs[arm.D3 - arm.D_OFFSET] = 1.1;
+        A5.fregs[arm.D4 - arm.D_OFFSET] = 1.1;
+        A5.fregs[arm.D5 - arm.D_OFFSET] = 1.1;
+        A5.fregs[arm.D6 - arm.D_OFFSET] = 1.1;
+        A5.fregs[arm.D7 - arm.D_OFFSET] = 1.1;
+
+        A5.regs[arm.X1]  = 2;
+        A5.regs[arm.X2]  = 2;
+        A5.regs[arm.X3]  = 2;
+        A5.regs[arm.X4]  = 2;
+        A5.regs[arm.X5]  = 2;
+        A5.regs[arm.X6]  = 2;
+        A5.regs[arm.X7]  = 2;
+
+        int trap_arm = A5.step(100);
+        assertEquals(0,trap_arm);
+
+        double result1 = A5.fregs[arm.D0 - arm.D_OFFSET];
+        assertEquals(22.8, result1, 0.00001);
+    }
+}
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/Compile.java b/chapter22/src/test/java/com/seaofnodes/simple/Compile.java
new file mode 100644
index 00000000..088055f9
--- /dev/null
+++ b/chapter22/src/test/java/com/seaofnodes/simple/Compile.java
@@ -0,0 +1,65 @@
+package com.seaofnodes.simple;
+
+import com.seaofnodes.simple.codegen.CodeGen;
+import com.seaofnodes.simple.node.FunNode;
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.ArrayList;
+import org.junit.Ignore;
+import org.junit.Test;
+import static org.junit.Assert.*;
+
+public class Compile {
+
+    private static Process run(String simple, String c) throws IOException, InterruptedException {
+        boolean USE_WSL = System.getProperty("os.name").startsWith("Windows");
+        CodeGen code = new CodeGen(simple);
+        code.parse().opto().typeCheck().instSelect("x86_64_v2", "SystemV").GCM().localSched().regAlloc().encode();
+        if (c != null) for (var n:code._start._outputs) if (n instanceof FunNode f && f._name.equals("main")) f._name = "simple_main";
+        code.exportELF("test.o");
+        var params = new ArrayList<String>();
+        if (USE_WSL) params.add("wsl.exe");
+        params.add("gcc");
+        params.add("-o");
+        params.add("test");
+        if (c != null) {
+            Files.writeString(Path.of("test.c"), c);
+            params.add("test.c");
+        }
+        params.add("test.o");
+        Process p = Runtime.getRuntime().exec(params.toArray(String[]::new));
+        assertEquals(0, p.waitFor());
+        return Runtime.getRuntime().exec(USE_WSL ? new String[]{"wsl.exe", "./test"}:new String[]{"./test"});
+    }
+
+    @Test
+    @Ignore
+    public void testCompile() throws IOException, InterruptedException {
+        var p = run("""
+                val testMy = { flt x ->
+                    flt guess = x;
+                    while( 1 ) {
+                        flt next = (x/guess + guess)/2;
+                        if( next == guess ) return guess;
+                        guess = next;
+                    }
+                };
+                ""","""
+
+                #include <stdio.h>
+
+                extern double testMy(double);
+
+                int main(int argc, char** argv) {
+                    printf("%f\\n", testMy(2.0));
+                    return 0;
+                }
+
+                """);
+        assertEquals(0, p.waitFor());
+        assertEquals("1.414214\n", new String(p.getInputStream().readAllBytes(), StandardCharsets.UTF_8));
+    }
+
+}
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/Eval2.java b/chapter22/src/test/java/com/seaofnodes/simple/Eval2.java
new file mode 100644
index 00000000..ecea97dd
--- /dev/null
+++ b/chapter22/src/test/java/com/seaofnodes/simple/Eval2.java
@@ -0,0 +1,450 @@
+package com.seaofnodes.simple;
+
+import com.seaofnodes.simple.codegen.CodeGen;
+import com.seaofnodes.simple.node.*;
+import com.seaofnodes.simple.print.IRPrinter;
+import com.seaofnodes.simple.type.*;
+import java.util.*;
+
+public abstract class Eval2 {
+
+    // A mapping from Node ID to evaluation data Object.
+    // Data Objsts are a boxed Long or Double; or an Object[] of fields, which
+    // themselves are just more Objects.
+    private static class Frame {
+        private static int UID=1;
+
+        private final IdentityHashMap<Node,Object> _data;
+        private Frame _prior;   // Prior frame in this sequence, means when making a new frame we can find old stuff
+        private int _refcnt;    // TODO: Use this in a sentence (free/recycle unused stack frames)
+        final int _uid = UID++; // Debugging aid
+        Frame(Frame prior) {
+            _prior = prior;
+            if( prior!=null ) prior._refcnt++;
+            _data = new IdentityHashMap<>();
+            _refcnt = 1;
+        }
+
+        // Dec ref count
+        void dec() {
+            assert _refcnt>0;
+            if( --_refcnt == 0 ) {
+                Frame prior = _prior;
+                _prior = null;
+                _data.clear();
+                // TODO: FREE LIST?
+                if( prior!=null )
+                    prior.dec();
+            }
+        }
+
+        // Put a mapping from Node->Object
+        Node put(Node n, Object d) {
+            assert d!=null;
+            return put0(n,d);
+        }
+        // Put a mapping from Node->Object?
+        Node put0(Node n, Object d) {
+            assert _refcnt>0;
+            _data.put(n,d);
+            return n;
+        }
+        // Get a mapped Node, perhaps using the prior stack frame crawl
+        Object get(Node n) {
+            assert _refcnt>0;
+            Object d = _data.get(n);
+            return d != null ? d
+                : _prior == null ? null
+                : _prior.get(n);
+        }
+
+        // Short debugging print
+        public String p() {
+            return "#"+_uid + (_prior==null ? "" : " >> " + _prior.p());
+        }
+        // Long debugging print
+        @Override public String toString() {
+            String s = "";
+            if( _prior != null ) s+= _prior+" << ";
+            s += "#"+_uid+"[ ";
+            for( Node n : _data.keySet() )
+                s += n + ":" + _data.get(n) + ",";
+            s += "]";
+
+            return s;
+        }
+    }
+
+    // Classic Closure; an environment (stack of frames) and an execution point
+    private static class Closure {
+        // Where to return too; either a CallEnd or a Function
+        final CFGNode _cc;
+
+        // Stack frame at the execution point.  Includes Closures which
+        // recursively include other stack frames
+        private Frame _frame;
+
+        Closure(CFGNode cc, Frame frame) {
+            _cc = cc;           // One of Fun, CallEnd or Stop (null)
+            _frame = frame;
+            assert _frame._refcnt >=0;
+            _frame._refcnt++;
+        }
+
+        FunNode fun() { return (FunNode)_cc; }
+        CallEndNode cend() { return (CallEndNode)_cc; }
+        boolean isStop() { return _cc instanceof StopNode; } // or Stop
+
+        //
+        void pushFrame() {
+            _frame = new Frame(_frame);
+            _frame._refcnt++;
+        }
+
+        @Override public String toString() {
+            return _cc.toString();
+        }
+    }
+
+    // CodeGen has the linker tables
+    public static CodeGen CODE;
+
+    // Current active Frame, to avoid having to pass it everywhere
+    public static Frame F;
+
+    public static String eval( CodeGen code, long arg ) { return eval(code,arg,1000); }
+    public static String eval( CodeGen code, long arg, int timeout ) {
+        SB trace = null; // new SB(); // TRACE, set to null for off, new SB() for on
+        // Force local scheduling phase
+        if( code._phase.ordinal() < CodeGen.Phase.TypeCheck .ordinal() )  code.typeCheck();
+        if( code._phase.ordinal() < CodeGen.Phase.Schedule  .ordinal() )  code.GCM();
+        if( code._phase.ordinal() < CodeGen.Phase.LocalSched.ordinal() )  code.localSched();
+        // Set global, so don't have to pass everywhere
+        CODE = code;
+
+        // Timer for when we run too long.  Ticks once per backedge or function call
+        int loopCnt = 0;
+
+        // Current value for each Node; boxed Long or Double; or an Object[] of
+        // fields, which themselves are just more Objects.
+        F = new Frame(null);
+
+        // Start at the START
+        CFGNode BB = code._start, prior = null;
+        // Return from main hits Stop
+        F.put(BB,new Closure(code._stop,F));
+
+
+        // ------------
+        // Evaluate until exit or timeout.  Each outer loop step computes
+        // all data nodes under some new Control.
+        while( true ) {
+            assert BB!=null;
+            traceCtrl(BB,trace);
+            if( trace!=null ) System.out.println(F.p());
+
+            // Parallel assign Phis
+            int i = BB instanceof RegionNode r
+                    ? parallelAssignPhis(r,prior,arg,trace)
+                    : 0;
+
+            // Compute the data nodes until BB control
+            for( ; i < BB.nOuts(); i++ )
+                if( !(BB.out(i) instanceof CFGNode) )
+                    step(BB.out(i), trace);
+
+            // Find the next control target
+            prior = BB;
+            BB = BB.uctrl();      // Next unique control target
+            switch( prior ) {
+            case StartNode start:  F = new Frame(F); break; // Frame for the call to main, as-if Called
+            case CallNode  call :  BB = call(call); break;
+            case IfNode    iff  :  Object p = val(iff.pred()); BB = iff.cproj( p==null || (p instanceof Long x && x==0L)  ? 1 : 0);  break;
+            case ReturnNode ret :  if( clj(ret.rpc()).isStop() ) return exit(ret); else BB = ret(ret); break;
+            case FunNode   fun  :  if( loopCnt++ > timeout ) return null;  break; // Timeout
+            case LoopNode  loop :  if( loopCnt++ > timeout ) return null;  break; // Timeout
+            case CallEndNode cend: break;
+            case CProjNode cproj:  break;
+            case RegionNode r   :  break;
+            default:               throw Utils.TODO();
+            }
+            assert !BB.isDead();
+        }
+    }
+
+
+    // Phi cache; size is limited to number of Phis at a merge point
+    private static final Object[] PHICACHE = new Object[256];
+    static int parallelAssignPhis(RegionNode r, CFGNode prior, long arg, SB trace) {
+
+        // Compute input path on Phis for this Region
+        int path = r._inputs.find( prior );
+        // Parameters read from prior frame, Phis from local frame
+        Frame frame = (r instanceof FunNode ? F._prior : F);
+        boolean isMain = r instanceof FunNode fun && fun.sig().isa(CodeGen.CODE._main);
+
+        // Parallel assign Phis.  First parallel read and cache
+        int i;
+        for( i = 0; i < r.nOuts(); i++ ) {
+            if( !(r.out(i) instanceof PhiNode phi) ) break;
+            if( isMain && phi instanceof ParmNode parm && parm._idx==2 )
+                PHICACHE[i] = arg; // Reading the initial arguments to main()
+            else {
+                Node n = phi instanceof ParmNode parm
+                    // RPC reads the Call directly;
+                    // Parms may not be linked, so read call args directly
+                    ? (parm._idx==0 ? prior : prior.in(parm._idx))
+                    // Phis read from path input
+                    :  phi.in(path);
+                PHICACHE[i] = frame.get(n);
+            }
+        }
+        // Parallel assign; might assign before read, so read from cache
+        for( int j=0; j < i; j++ )
+            traceData(F.put0(r.out(j),PHICACHE[j]),trace);
+        // Return point in basic block past last Phi
+        return i;
+    }
+
+
+    // Make a call.
+    private static CFGNode call( CallNode call ) {
+        // Set up the Return PC and return frame (which is just the current frame).
+        // Really making a Continuation, but it's just a Closure
+        Closure cont = new Closure(call.cend(),F);
+        // Set the return continuation into the current frame RPC
+        F.put(call, cont );
+        // Next Frame to use
+        F = new Frame(F);
+        // Target function and environment
+        return CODE.link(tfp(call.fptr()));
+    }
+
+    private static CFGNode ret( ReturnNode ret ) {
+        // Fetch return expression value and continuation from current frame
+        Object rez = val(ret.expr());
+        Closure cont = clj(ret.rpc());
+        // Lower Frame reference count; might delete frame
+        F.dec();                // Lower ref count
+        // Install replacement Frame; set return result over the CallEnd
+        F = cont._frame;
+        F.put0(cont._cc,rez);   // Set return value into CallEnd
+        return cont._cc;        // Return CallEnd as the new control
+    }
+
+    private static String exit( ReturnNode ret ) {
+        return prettyPrint(ret.expr()._type,val(ret.expr()));
+    }
+
+    // Take a worklist step: one data op from the current Control is updated.
+    private static void step(Node n, SB trace) {
+        if( n instanceof PhiNode ) return;
+        // Compute new value
+        F.put0(n,compute(n));
+        traceData(n,trace);
+        // Also do any following projections, which are not in the local schedule otherwise
+        if( n instanceof MultiNode )
+            for( Node use : n._outputs )
+                step(use,trace);
+    }
+
+    // From here down shamelessly copied from Evaluator, written by @Xmilia
+    private static Object compute( Node n ) {
+        return switch( n ) {
+        case AddFNode     adf  -> d(adf.in(1)) +  d(adf.in(2));
+        case AddNode      add  -> x(add.in(1)) +  x(add.in(2));
+        case AndNode      and  -> x(and.in(1)) &  x(and.in(2));
+        case BoolNode.EQF eqf  -> d(eqf.in(1)) == d(eqf.in(2)) ? 1L : 0L;
+        case BoolNode.LEF lef  -> d(lef.in(1)) <= d(lef.in(2)) ? 1L : 0L;
+        case BoolNode.LTF ltf  -> d(ltf.in(1)) <  d(ltf.in(2)) ? 1L : 0L;
+        case BoolNode.EQ  eq   -> Objects.equals(val(eq.in(1)), val(eq.in(2))) ? 1L : 0L; // Bool EQ supports pointers, nil, and integers
+        case BoolNode.LE  le   -> x(le .in(1)) <= x(le .in(2)) ? 1L : 0L;
+        case BoolNode.LT  lt   -> x(lt .in(1)) <  x(lt .in(2)) ? 1L : 0L;
+        case CastNode    cast  -> val(cast.in(1));
+        case ConstantNode con  -> con(con._con);
+        case DivFNode     dvf  -> d(dvf.in(2))==0 ? 0D : d(dvf.in(1)) /  d(dvf.in(2));
+        case DivNode      div  -> x(div.in(2))==0 ? 0L : x(div.in(1)) /  x(div.in(2));
+        case LoadNode     ld   -> load(ld);
+        case MinusFNode   mnf  -> - d(mnf.in(1));
+        case MinusNode    sub  -> - x(sub.in(1));
+        case MulFNode     mlf  -> d(mlf.in(1)) *  d(mlf.in(2));
+        case MulNode      mul  -> x(mul.in(1)) *  x(mul.in(2));
+        case NewNode      alloc-> alloc(alloc);
+        case NotNode      not  -> x(not.in(1)) == 0 ? 1L : 0L;
+        case OrNode       or   -> x(or .in(1)) |  x(or .in(2));
+        case ProjNode     proj -> proj._type instanceof TypeMem ? "$mem" : val(proj.in(0));
+        case ReadOnlyNode read -> val(read.in(1));
+        case SarNode      sar  -> x(sar.in(1)) >> x(sar.in(2));
+        case MemMergeNode merge-> "$mem";
+        case ShlNode      shl  -> x(shl.in(1)) << x(shl.in(2));
+        case ShrNode      shr  -> x(shr.in(1)) >>>x(shr.in(2));
+        case StoreNode    st   -> store(st);
+        case SubNode      sub  -> x(sub.in(1)) -  x(sub.in(2));
+        case SubFNode     sbf  -> d(sbf.in(1)) -  d(sbf.in(2));
+        case ToFloatNode  toflt-> (double)x(toflt.in(1));
+        case XorNode      xor  -> x(xor.in(1)) ^  x(xor.in(2));
+        default -> throw Utils.TODO();
+        };
+    }
+
+    // Fetch without unboxing, searching up-Frame
+    static Object val( Node n ) { return F.get(n); }
+    // Fetch and unbox as primitive long
+    static long   x( Node n ) { Object d = F.get(n); return d==null ? 0 : (Long)  F.get(n);  }
+    // Fetch and unbox as primitive double
+    static double d( Node n ) { Object d = F.get(n); return d==null ? 0 : (Double)F.get(n);  }
+    // Fetch and unbox a function constant
+    static TypeFunPtr tfp(Node n) { return (TypeFunPtr)F.get(n); }
+    // Fetch and unbox a closure
+    static Closure clj(Node n) { return (Closure)F.get(n); }
+
+    // Java box ints and floats.  Other things can just be null or some informative string
+    private static Object con( Type t ) {
+        return switch ( t ) {
+        case TypeInteger i -> i.isConstant() ? (Long  )i.value() : "INT";
+        case TypeFloat   f -> f.isConstant() ? (Double)f.value() : "FLT";
+        case TypeMemPtr tmp -> tmp;
+        case TypeFunPtr tfp -> tfp;
+        case TypeMem mem -> "MEM";
+        default -> null;
+        };
+    }
+
+    // Convert array size to array element count
+    private static int offToIdx( long off, TypeStruct t) {
+        off -= t.aryBase();
+        int scale = t.aryScale();
+        long mask = (1L << scale)-1;
+        assert (off & mask) == 0;
+        return (int)(off>>scale);
+    }
+
+    // Builds and returns a pointer Object
+    private static Object alloc(NewNode alloc) {
+        TypeStruct type = alloc._ptr._obj;
+        if( type.isAry() ) {
+            long sz = (Long)val(alloc.in(1));
+            long x = offToIdx(sz, type);
+            int n = (int)x;
+            if( n!=x || n<0 )
+                throw new NegativeArraySizeException(""+n);
+            Object[] ary = new Object[n]; // Array body
+            var elem = type._fields[1]._type;
+            if (elem instanceof TypeInteger) {
+                Arrays.fill( ary, 0L );
+            } else if (elem instanceof TypeFloat) {
+                Arrays.fill( ary, 0D );
+            } else {
+                assert elem instanceof TypeMemPtr || elem instanceof TypeFunPtr;
+            }
+            return ary;
+        }
+
+        int num = type._fields.length;
+        Object[] ptr = new Object[num];
+        for( int i=0; i<num; i++ )
+            ptr[i] = con(type._fields[i]._type.makeZero());
+        return ptr;
+    }
+
+    private static Object load( LoadNode ld ) {
+        TypeMemPtr tmp = (TypeMemPtr)ld.ptr()._type;
+        Object[] fs = (Object[])val(ld.ptr());
+        if( ld._name.equals("#") )
+            return (long)fs.length;
+        int idx = tmp._obj.isAry()
+            ? offToIdx(x(ld.off()),tmp._obj)
+            : tmp._obj.find(ld._name);
+        return fs[idx];
+    }
+
+    private static Object store( StoreNode st ) {
+        if( st._name.equals("#") )
+            return "$mem";      // Eval stores the length in the java object[], no need to set it now
+        TypeMemPtr tmp = (TypeMemPtr)st.ptr()._type;
+        Object[] fs = (Object[])val(st.ptr());
+        int idx = tmp._obj.isAry()
+            ? offToIdx(x(st.off()),tmp._obj)
+            : tmp._obj.find(st._name);
+        Object val = val(st.val());
+        fs[idx] = val;
+        return "$mem";
+    }
+
+
+    // ------------------------------------------------------------------------
+    private static final IdentityHashMap<Object,Object> VISIT = new IdentityHashMap<>();
+
+
+    static void traceCtrl( CFGNode BB, SB sb ) {
+        if( sb==null ) return;
+        IRPrinter.printLine(BB,sb.p("--- "));
+        System.out.print(sb);
+        sb.clear();
+    }
+    static void traceData( Node n, SB sb ) {
+        if( sb==null ) return;
+        IRPrinter.printLine(n,sb).unchar();
+        _print( n._type, F.get(n), sb.p('\t'), VISIT );
+        System.out.println(sb);
+        sb.clear();
+        VISIT.clear();
+    }
+
+    // Use type to print x as a string.  Uses a new VISIT table so the debugger
+    // doesn't try to reuse VISIT if stopping mid-print.  The trace code reuses
+    // VISIT endlessly for some minor speed hope
+    static String prettyPrint( Type t, Object x ) { return _print(t,x,new SB(), new IdentityHashMap<>()).toString(); }
+    static SB _print( Type t, Object x, SB sb, IdentityHashMap<Object,Object> visit ) {
+        if( x instanceof String s ) return sb.p(s);
+        if( x == null ) return sb.p("null");
+        return switch( t ) {
+        case TypeInteger i -> sb.p(  (Long)x);
+        case TypeFloat   f -> sb.p((Double)x);
+        case TypeMemPtr tmp -> {
+            if( visit.containsKey(x) ) yield sb.p("$cyclic");
+            visit.put(x,x);
+            // Since never can close the type cycle, without cyclic types, have
+            // to handle FRefs even here
+            if( tmp.isFRef() )
+                tmp = tmp.makeFrom(((TypeMemPtr)Parser.TYPES.get(tmp._obj._name))._obj);
+
+            Object[] xs = (Object[])x; // Array of fields
+            if( tmp._obj.isAry() ) {
+                Type elem = tmp._obj._fields[1]._type;
+                if( elem == TypeInteger.U8 ) {
+                    // Shortcut u8[] as a String
+                    for( Object o : xs )
+                        sb.p((char)(long)(Long)o);
+                } else {
+                    // Array of elements
+                    elem.print(sb).p("[ ");
+                    for( Object o : xs )
+                        _print( elem, o, sb, visit ).p( "," );
+                    sb.unchar().p("]");
+                }
+            } else {
+                sb.p(tmp._obj._name).p("{");
+                Field[] flds = tmp._obj._fields;
+                for( int i=0; i<flds.length; i++ )
+                    _print( flds[i]._type,xs[i], sb.p(flds[i]._fname).p("="), visit ).p(",");
+                sb.unchar().p("}");
+            }
+            yield sb;
+        }
+        case TypeFunPtr tfp -> sb.p(x.toString());
+        case TypeRPC rpc -> sb.p(x.toString());
+        case TypeMem mem -> sb.p("$mem");
+        case TypeTuple tt -> {
+            if( tt._types.length>1 && tt._types[1] instanceof TypeMemPtr )
+                // Assume a NewNode
+                yield _print( tt._types[1], x, sb, visit );
+            throw Utils.TODO();
+        }
+        case Type tt -> {
+            if( tt == Type.NIL ) yield sb.p("null");
+            throw Utils.TODO();
+        }
+        };
+    }
+}
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/EvalArm64.java b/chapter22/src/test/java/com/seaofnodes/simple/EvalArm64.java
new file mode 100644
index 00000000..4a4cf25c
--- /dev/null
+++ b/chapter22/src/test/java/com/seaofnodes/simple/EvalArm64.java
@@ -0,0 +1,360 @@
+package com.seaofnodes.simple;
+
+import com.seaofnodes.simple.codegen.Encoding;
+import com.seaofnodes.simple.node.cpus.arm.arm;
+
+public class EvalArm64 {
+    // Memory image, always 0-based
+    public final byte[] _buf;
+
+    // GPRs
+    final long[] regs;
+    // FRs
+    final double[] fregs;
+
+    int _pc;
+
+    // Start of free memory for allocation
+    int _heap;
+
+    // Cycle counters
+    int _cycle;
+
+    // flags
+    boolean N = false;
+    boolean Z = false;
+    boolean C = false;
+    boolean V = false;
+
+    EvalArm64(byte[] buf, int stackSize) {
+        _buf = buf;
+        regs  = new long[32];
+        fregs = new double[32];
+        // Stack grows down, heap grows up
+        regs[arm.RSP] = _heap = stackSize;
+        _pc = 0;
+    }
+
+    // Little endian
+    public int  ld1s(int x) { return _buf[x  ]     ; }
+    public int  ld1z(int x) { return _buf[x  ]&0xFF; }
+    public int  ld2s(int x) { return ld1z(x) | ld1s(x+1)<< 8; }
+    public int  ld2z(int x) { return ld1z(x) | ld1z(x+1)<< 8; }
+    public int  ld4s(int x) { return ld2z(x) | ld2s(x+2)<<16; }
+    public long ld8 (int x) { return (long)ld4s(x)&0xFFFFFFFFL | ((long)ld4s(x+4))<<32; }
+
+
+    public float  ld4f(int x) { return Float.intBitsToFloat(ld4s(x)); }
+    public double ld8f(int x) { return Double.longBitsToDouble(ld8(x)); }
+
+    public void st1(int x, int  val) { _buf[x] = (byte)val; }
+    public void st2(int x, int  val) { st1(x,val); st1(x+1,val>> 8); }
+    public void st4(int x, int  val) { st2(x,val); st2(x+2,val>>16); }
+    public void st8(int x, long val) { st4(x,(int)val); st2(x+4,(int)(val>>32)); }
+
+
+    public int step(int maxops) {
+        int trap = 0;
+        long rval = 0;
+        double frval = 0;
+        int pc = _pc;
+        int cycle = _cycle;
+        boolean is_f = false;
+        outer:
+        for(int icount = 0; icount < maxops; icount++) {
+            int ir = 0;
+            rval = 0;
+            frval = 0;
+            cycle++;
+
+            if( pc >= _buf.length ) {
+                trap = 1 + 1;  // Handle access violation on instruction read.
+                break;
+            }
+
+            if( (pc & 3)!=0 ) {
+                trap = 1;  // Handle PC-misaligned access
+                break;
+            }
+
+            // Load instruction from image buffer at PC
+            ir = ld4s( pc );
+
+            int rdid = ir & 0x1f;
+            // [31:24]
+            int opcode1 = (ir >> 24) & 0xFF;
+            // [31:26]
+            int opcode2 = (ir >> 26) & 0x3F;
+            switch(opcode2) {
+                case 5: {
+                    //b
+                    int imm26 = ir << 6 >> 6;
+
+                    pc = pc + (imm26 * 4) - 4;
+                    // won't hit pc += 4 at the bottom because continue
+                    // do it manually
+                    pc += 4;
+                    rdid = -1;
+                    continue ;
+                }
+                case 0x25: {
+                    // bl (just calloc)
+                    rval = pc + 4;
+                    regs[arm.X30] = rval;
+                    if(pc + 4 == 0) {
+                        regs[rdid] = rval;
+                        break outer;
+                    }
+                    int imm26 = (ir & 0x03FFFFFF);
+                    int imm = (imm26 << 6) >> 6;
+                    pc = pc + (imm << 2) ;
+
+                    if (pc == Encoding.SENTINAL_CALLOC) {
+                        long size = regs[arm.X0]*regs[arm.X1];
+                        regs[arm.X0] = _heap;
+                        _heap += (int)size;
+                        // unwind pc
+                        pc = (int)rval - 4;
+                    }
+                    continue;
+                }
+            }
+            // for the opcode we just match for bits[31:24];
+            switch(opcode1) {
+                case 0xD2: {
+                    // movz
+                    // get immediate
+                    rval = (ir >> 5) & 0x7FFF;
+                    break;
+                }
+                case 0x5c: {
+                    // ldr
+                    is_f = true;
+                    // address = delta
+                    int address = ir << 8 >> 13;
+                    address *= 4;
+                    if(address >= _buf.length-3) trap = (5 + 1);
+                    frval = ld8f(pc + address);
+                    break;
+                }
+
+                case 0xF9: {
+                    // str
+                    // rn
+                    int base = ir >> 5 & 0x1F;
+                    int imm = (ir >> 10) & 0xFFF;
+                    rval = regs[base] + imm;
+                    switch(ir <<8 >> 30) {
+                        case 0x0: {
+                            // store
+                            _buf[(int)rval] = (byte)regs[rdid];
+                            if(rdid == 30) {
+                                System.out.print("Here");
+                            }
+                            rdid = -1;
+                            break;
+                        }
+                        case 0x1: {
+                            // load
+                            rval = _buf[(int)rval];
+                            break;
+                        }
+                        default: trap = (2+1);
+                    }
+                    break;
+                }
+                case 0x54: {
+                    // b.cond
+                    int imm19 = ir << 8 >> 13;
+                    imm19 = pc + (imm19 * 4) - 4;
+                    rdid = -1;
+
+                    switch(ir & 0xF) {
+                        case 0x0: if(Z)  pc = imm19; break; // eq
+                        case 0x1: if(!Z) pc = imm19; break; // ne
+                        case 0x2: if(C)  pc = imm19; break; // cs
+                        case 0x3: if(!C) pc = imm19; break;
+                        case 0x4: if(N) pc = imm19; break; // mi
+                        case 0x5: if(!N) pc = imm19; break; // pl
+                        case 0x6: if(V) pc = imm19; break; // vs
+                        case 0x7: if(!V) pc = imm19; break; // vc
+                        case 0x8: if(C && !Z) pc = imm19; break; // hi
+                        case 0x9: if(!C || Z) pc = imm19; break; // ls
+                        case 0xA: if(N == V) pc = imm19; break; // ge
+                        case 0xB: if(N != V) pc = imm19; break; // lt
+                        case 0xC: if(!Z && N == V) pc = imm19; break; // gt
+                        case 0xD: if(Z || N != V) pc = imm19; break; // le
+                        case 0xE: pc = imm19; break; // always executed(al)
+                        default: trap = (2+1);
+                    }
+                    break;
+                }
+                case 0x9a: {
+                    // conditional select(csel)
+                    int rm = (ir >> 16) & 0x1F;
+                    switch((ir >> 12) & 0xF) {
+                        case 0x0: if(Z)  rval = regs[rm]; break; // eq
+                        case 0x1: if(!Z) rval = regs[rm]; break; // ne
+                        case 0x2: if(C)  rval = regs[rm]; break; // cs
+                        case 0x3: if(!C) rval = regs[rm]; break;
+                        case 0x4: if(N) rval  =  regs[rm]; break; // mi
+                        case 0x5: if(!N) rval = regs[rm]; break; // pl
+                        case 0x6: if(V) rval = regs[rm]; break; // vs
+                        case 0x7: if(!V) rval = regs[rm]; break; // vc
+                        case 0x8: if(C && !Z) rval = regs[rm]; break; // hi
+                        case 0x9: if(!C || Z) rval = regs[rm]; break; // ls
+                        case 0xA: if(N == V) rval = regs[rm]; break; // ge
+                        case 0xB: if(N != V) rval = regs[rm]; break; // lt
+                        case 0xC: if(!Z && N == V) rval  = regs[rm]; break; // gt
+                        case 0xD: if(Z || N != V) rval = regs[rm]; break; // le
+                        case 0xE: rval = regs[rm]; break; // always executed(al)
+                        default: {
+                           rval =  regs[(ir >> 5) & 0x1F];
+                        }
+                    }
+                    break;
+                }
+                case 0xeb: {
+                    // subs(shifted register)
+                    int rn = (ir >> 5) &  0x1F;
+                    int rm = (ir >> 16) & 0x1F;
+                    int lhs = (int)regs[rn];
+                    int rhs = (int)regs[rm];
+                    rval = lhs - rhs;
+
+                    // set flags as a side effect
+                    Z = (rval == 0);
+                    N = (rval < 0);
+                    C = lhs >= rhs;
+
+                    boolean sign_lhs = (lhs >>> 63) != 0;
+                    boolean sign_rhs = (rhs >>> 63) != 0;
+                    boolean sign_res = (rval >>> 63) != 0;
+                    V = (sign_lhs != sign_rhs) && (sign_res != sign_lhs);
+                    rdid = -1;
+                    break;
+                }
+                case 0xF1: {
+                    // subs(immediate)
+                    int rn = (ir >> 5) & 0x1F;
+                    int immediate = ir << 10 >> 20;
+                    int lhs = (int)regs[rn];
+
+                    rval = lhs - immediate;
+
+                    // set flags as a side effect
+                    Z = (rval == 0);
+                    N = (rval < 0);
+                    C = lhs >= immediate;
+
+                    boolean sign_lhs = (lhs >>> 63) != 0;
+                    boolean sign_rhs = (immediate >>> 63) != 0;
+                    boolean sign_res = (rval >>> 63) != 0;
+                    V = (sign_lhs != sign_rhs) && (sign_res != sign_lhs);
+                    rdid = -1;
+                    break;
+                }
+                case 0x8B: {
+                    // add(shifted register)
+                    int rn = (ir >> 5)  & 0x1F;
+                    int rm = (ir >> 16) & 0x1F;
+                    long lhs = regs[rn];
+                    long rhs = regs[rm];
+                    rval = lhs + rhs;
+                    break;
+                }
+                case 0x91: {
+                    // add(immediate)
+                    int rn = (ir >> 5) & 0x1F;
+                    int immediate = ir << 10 >> 20;
+                    rval = regs[rn] + immediate;
+                    break;
+                }
+                case 0xD3: {
+                    // lsl
+                    int immr = ir << 10 >> 26;
+                    rval     = 64 - immr;
+                    break;
+                }
+                case 0xAA: {
+                    // MOV(register)
+                    int rm = (ir >> 16) & 0x1F;
+                    rval = regs[rm];
+                    break;
+                }
+                case 0xD6: {
+                    rdid = -1;
+                    if(ld4s(pc + 4) == 0) {
+                        break outer;
+                    }
+                }
+                // bitwise
+                case 0x8A: {
+                    // AND
+                    int rn = (ir >> 5) & 0x1F;
+                    int rm = (ir >> 16) & 0x1F;
+                    rval = regs[rn] & regs[rm];
+                    break;
+                }
+                // floats
+                case 0x1E: {
+                    is_f = true;
+                    int rs1 = (ir >> 5) & 0x1F;
+                    int rs2 = (ir >> 16) & 0x1F;
+
+                    int op = (ir >> 10) & 0x3F;
+                    switch(op) {
+                        case 16: frval = fregs[rs1]; break; // fmov
+                        case 10:frval = fregs[rs1] + fregs[rs2]; break; // fadd
+
+                        case 6: if (fregs[rs2] == 0) frval = 0; else frval = fregs[rs1] / fregs[rs2]; break; // fdiv
+                        case 8: {
+                            // fcmp
+                            double lhs  = fregs[rs1];
+                            double rhs = fregs[rs2];
+
+                            Z = (lhs == rhs);
+                            N = (lhs < rhs);
+                            C = lhs >= rhs;
+                            V = Double.isNaN(lhs) || Double.isNaN(rhs);
+                            rdid = -1;
+
+                            break;
+                        }
+                        case 2: frval = fregs[rs1] * fregs[rs2]; break; // fmul
+                        case 14: frval = fregs[rs1] - fregs[rs2]; break; // fsub
+                        default: trap = (2+1);
+                    }
+                    break;
+                }
+                case 0x9e: {
+                    // scvtf
+                    is_f = true;
+                    int rs1 = (ir >> 5) & 0x1F;
+                    frval = (double)regs[rs1];
+                    break;
+                }
+                default: trap = (2+1);
+            }
+            if(trap != 0) {
+                _pc = pc;
+                break;
+            }
+            if(rdid != -1) {
+                if(is_f) {fregs[rdid] = frval; is_f = false;}
+                else regs[rdid] = rval;
+            }
+
+            pc += 4;
+        }
+        // Handle traps and interrupts.
+        if(trap != 0) {
+            return trap;
+        }
+        _cycle = cycle;
+        _pc = pc;
+        return 0;
+    }
+
+
+}
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/EvalRisc5.java b/chapter22/src/test/java/com/seaofnodes/simple/EvalRisc5.java
new file mode 100644
index 00000000..bad22d52
--- /dev/null
+++ b/chapter22/src/test/java/com/seaofnodes/simple/EvalRisc5.java
@@ -0,0 +1,352 @@
+ package com.seaofnodes.simple;
+
+/** Simple RISC5 CPU Emulator
+ *
+ * Original works credit Charles Lohr.
+ * This is a complete rewrite in Java.
+ *
+ * Load code into memory and go!
+ */
+
+import com.seaofnodes.simple.codegen.Encoding;
+import com.seaofnodes.simple.node.cpus.riscv.riscv;
+
+import java.util.Arrays;
+
+ public class EvalRisc5 {
+
+    // Memory image, always 0-based
+    public final byte[] _buf;
+
+    // GPRs
+    final long[] regs;
+    // FRs
+    final double[] fregs;
+    // PC
+    int _pc;
+
+    // Start of free memory for allocation
+    int _heap;
+
+    // Cycle counters
+    int _cycle;
+
+    EvalRisc5( byte[] buf, int stackSize ) {
+        _buf  = buf;
+        regs  = new long[32];
+        fregs = new double[32];
+        // Stack grows down, heap grows up
+        regs[riscv.RSP] = _heap = stackSize;
+        _pc = 0;
+    }
+
+    // Little endian
+    public int  ld1s(int x) { return _buf[x  ]     ; }
+    public int  ld1z(int x) { return _buf[x  ]&0xFF; }
+    public int  ld2s(int x) { return ld1z(x) | ld1s(x+1)<< 8; }
+    public int  ld2z(int x) { return ld1z(x) | ld1z(x+1)<< 8; }
+    public int  ld4s(int x) { return ld2z(x) | ld2s(x+2)<<16; }
+    public long ld8 (int x) { return (long)ld4s(x)&0xFFFFFFFFL | ((long)ld4s(x+4))<<32; }
+
+    public float  ld4f(int x) { return Float.intBitsToFloat(ld4s(x)); }
+    public double ld8f(int x) { return Double.longBitsToDouble(ld8(x)); }
+
+
+    public void st1(int x, int  val) { _buf[x] = (byte)val; }
+    public void st2(int x, int  val) { st1(x,val); st1(x+1,val>> 8); }
+    public void st4(int x, int  val) { st2(x,val); st2(x+2,val>>16); }
+    public void st8(int x, long val) { st4(x,(int)val); st2(x+4,(int)(val>>32)); }
+
+    // Note: only a few bits are used.  (Machine = 3, User = 0)
+    // Bits 0..1 = privilege.
+    // Bit 2 = WFI (Wait for interrupt)
+    // Bit 3+ = Load/Store reservation LSBs.
+    int _extraflags;
+
+    public int step( int maxops ) {
+        int trap = 0;
+        long rval = 0;
+        double frval = 0;
+        int pc = _pc;
+        int cycle = _cycle;
+        boolean is_f = false;
+        outer:
+        for( int icount = 0; icount < maxops; icount++ ) {
+            int ir = 0;
+            rval = 0;
+            cycle++;
+
+            if( pc >= _buf.length ) {
+                trap = 1 + 1;  // Handle access violation on instruction read.
+                break;
+            }
+            if( (pc & 3)!=0 ) {
+                trap = 1;  // Handle PC-misaligned access
+                break;
+            }
+
+            // Load instruction from image buffer at PC
+            ir = ld4s( pc );
+            int rdid = (ir >> 7) & 0x1f;
+
+            switch( ir & 0x7f ) {
+            case 0x37: // LUI (0b0110111)
+                rval = ( ir & 0xfffff000 );
+                break;
+            case 0x17: // AUIPC (0b0010111)
+                rval = pc + ( ir & 0xfffff000 );
+                break;
+            case 0x6F: { // JAL (0b1101111)
+                int reladdy = ((ir & 0x80000000)>>11) | ((ir & 0x7fe00000)>>20) | ((ir & 0x00100000)>>9) | ((ir&0x000ff000));
+                if( (reladdy & 0x00100000)!=0 ) reladdy |= 0xffe00000; // Sign extension.
+                rval = pc + 4;
+                pc = pc + reladdy - 4;
+                break;
+            }
+            case 0x67: { // JALR (0b1100111)
+                int imm = ir >> 20;
+
+                int imm_se = imm | (( (imm & 0x800)!=0 ) ? 0xfffff000 : 0);
+                rval = pc + 4;
+                pc = ( ((int)regs[ (ir >> 15) & 0x1f ] + imm_se) & ~1) - 4;
+                // Return from top-level ; exit sim
+                if( pc+4==0 ) {
+                    if( rdid!=0 ) regs[rdid] = rval; // Write PC into register before exit
+                    break outer;
+                }
+                // Inline CALLOC effect
+                if( pc == Encoding.SENTINAL_CALLOC ) {
+                    int size = (int)(regs[10]*regs[11]);
+                    regs[10] = _heap; // Return next free address
+                    // Pre-zeroed; epsilon (null) collector, never recycles memory so always zero
+                    // Arrays.fill(_buf,_heap,_heap+size, (byte) 0 );
+                    _heap += size;
+                    pc = (int)(rval - 4); // Unwind PC, as-if returned from calloc
+                }
+                break;
+            }
+            case 0x63: { // Branch (0b1100011)
+                int immm4 = ((ir & 0xf00)>>7) | ((ir & 0x7e000000)>>20) | ((ir & 0x80) << 4) | ((ir >> 31)<<12);
+                if( (immm4 & 0x1000)!=0 ) immm4 |= 0xffffe000;
+                long rs1 = regs[(ir >> 15) & 0x1f];
+                long rs2 = regs[(ir >> 20) & 0x1f];
+                immm4 = pc + immm4 - 4;
+                rdid = 0;
+                if( switch( (ir >> 12) & 0x7 ) {
+                    case 0 -> rs1 == rs2;
+                    case 1 -> rs1 != rs2;
+                    case 4 -> rs1 <  rs2;
+                    case 5 -> rs1 >= rs2;
+                    case 6 -> Long.compareUnsigned(rs1,rs2) <  0;  //BLTU
+                    case 7 -> Long.compareUnsigned(rs1,rs2) >= 0;  //BGEU
+                    default -> { trap = (2+1); yield false; }
+                    } )   pc = immm4;
+                break;
+            }
+            case 0x03: { // Load (0b0000011)
+                int rs1 = (int)regs[(ir >> 15) & 0x1f]; // Address chop to 32b
+                int imm = ir >> 20;
+                int imm_se = imm | (( (imm & 0x800)!=0 ) ? 0xfffff000 : 0 );
+                int rsval = rs1 + imm_se;
+
+                if( rsval >= _buf.length-3 ) {
+                    trap = (5+1);
+                    rval = rsval;
+                } else {
+                    switch( ( ir >> 12 ) & 0x7 ) {
+                        //LB, LH, LW, LBU, LHU
+                    case 0: rval = ld1s( rsval ); break;
+                    case 1: rval = ld2s( rsval ); break;
+                    case 2: rval = ld4s( rsval ); break;
+                    case 3: rval = ld8 ( rsval ); break;
+                    case 4: rval = ld1z( rsval ); break;
+                    case 5: rval = ld2z( rsval ); break;
+                    case 6: rval = ld4s( rsval ); break;
+                    default: trap = (2+1);
+                    }
+                }
+                break;
+            }
+            // floats
+            case 0x7: {
+                is_f = true;
+                int rs1 = (int)regs[(ir >> 15) & 0x1f]; // Address chop to 32b
+                int imm = ir >> 20;
+                int imm_se = imm | (( (imm & 0x800)!=0 ) ? 0xfffff000 : 0 );
+                int rsval = rs1 + imm_se;
+
+                if( rsval >= _buf.length-3 ) {
+                    trap = (5+1);
+                    rval = rsval;
+                } else {
+                    switch( ( ir >> 12 ) & 0x7 ) {
+                    case 2: frval = ld4f( rsval ); break;
+                    case 3: frval = ld8f( rsval ); break;
+                    default: trap = (2+1);
+                    }
+                }
+                break;
+            }
+
+            case 0x23: { // Store 0b0100011
+                int  rs1 = (int)regs[(ir >> 15) & 0x1f]; // Address chop to 32b
+                long rs2 = regs[(ir >> 20) & 0x1f];
+                int addy = ( ( ir >> 7 ) & 0x1f ) | ( ( ir & 0xfe000000 ) >> 20 );
+                if( (addy & 0x800)!=0 ) addy |= 0xfffff000;
+                addy += rs1;
+                rdid = 0;
+
+                if( addy >= _buf.length-3 ) {
+                    trap = (7+1); // Store access fault.
+                    rval = addy;
+                } else {
+                    switch( ( ir >> 12 ) & 0x7 ) { //SB, SH, SW
+                    case 0: st1( addy, (int)rs2 ); break;
+                    case 1: st2( addy, (int)rs2 ); break;
+                    case 2: st4( addy, (int)rs2 ); break;
+                    case 3: st8( addy,      rs2 ); break;
+                    default: trap = (2+1);
+                    }
+                }
+                break;
+            }
+            case 0x13:   // Op-immediate 0b0010011
+            case 0x33: { // Op           0b0110011
+                int imm = ir >> 20;
+                imm = imm | (( (imm & 0x800)!=0 ) ? 0xfffff000 : 0);
+                long rs1 = regs[(ir >> 15) & 0x1f];
+                boolean is_reg = (ir & 0x20)!=0;
+                long rs2 = is_reg ? regs[imm & 0x1f] : imm;
+
+                if( is_reg && ( ir & 0x02000000 )!=0 ) {
+                    switch( (ir>>12)&7 ) { //0x02000000 = RV32M
+                    case 0: rval = rs1 * rs2; break; // MUL
+                    case 1: rval = (int)((long)((int)rs1) * (long)((int)rs2)) >> 32; break; // MULH
+                    case 2: rval = (int)((long)((int)rs1) * (long)rs2) >> 32; break; // MULHSU
+                    case 3: rval = (int)((long)rs1 * (long)rs2) >> 32; break; // MULHU
+                    case 4: if( rs2 == 0 ) rval = -1; else rval = ((int)rs1 == Integer.MIN_VALUE && (int)rs2 == -1) ? rs1 : ((int)rs1 / (int)rs2); break; // DIV
+                    case 5: if( rs2 == 0 ) rval = 0xffffffff; else rval = rs1 / rs2; break; // DIVU
+                    case 6: if( rs2 == 0 ) rval = rs1; else rval = ((int)rs1 == Integer.MIN_VALUE && (int)rs2 == -1) ? 0 : ((int)((int)rs1 % (int)rs2)); break; // REM
+                    case 7: if( rs2 == 0 ) rval = rs1; else rval = rs1 % rs2; break; // REMU
+                    }
+                } else {
+                    rval = switch( (ir >> 12) & 7 ) { // These could be either op-immediate or op commands.  Be careful.
+                    case 0 -> (is_reg && (ir & 0x40000000) != 0) ? (rs1 - rs2) : (rs1 + rs2);
+                    case 1 -> rs1 << (rs2 & 0x1F);
+                    case 2 -> (rs1 < rs2) ? 1 : 0;
+                    case 3 -> (rs1 < rs2) ? 1 : 0;
+                    case 4 -> rs1 ^ rs2;
+                    case 5 -> (ir & 0x40000000) != 0 ? (((int) rs1) >> (rs2 & 0x1F)) : (rs1 >> (rs2 & 0x1F));
+                    case 6 -> rs1 | rs2;
+                    case 7 -> rs1 & rs2;
+                    default -> rval;
+                  };
+                }
+                break;
+            }
+            case 0x0f:      // 0b0001111
+                rdid = 0;   // fencetype = (ir >> 12) & 0b111; We ignore fences in this impl.
+                break;
+            case 0x73: // Zifencei+Zicsr  (0b1110011)
+                trap = (2+1); // Note micrrop 0b100 == undefined.
+                break;
+
+            case 0x2f: { // RV32A (0b00101111)
+                long rs1 = regs[(ir >> 15) & 0x1f];
+                long rs2 = regs[(ir >> 20) & 0x1f];
+                int irmid = ( ir>>27 ) & 0x1f;
+
+                // We don't implement load/store from UART or CLNT with RV32A here.
+                if( rs1 >= _buf.length-3 ) {
+                    trap = (7+1); //Store/AMO access fault
+                    rval = rs1;
+                } else {
+                    rval = ld4s( (int)rs1 );
+
+                    // Referenced a little bit of https://github.com/franzflasch/riscv_em/blob/master/src/core/core.c
+                    boolean dowrite = true;
+                    switch( irmid )                                            {
+                    case 2: //LR.W (0b00010)
+                        dowrite = false;
+                        _extraflags = (_extraflags & 0x07) | (int)(rs1<<3);
+                        break;
+                    case 3: { //SC.W (0b00011) (Make sure we have a slot, and, it's valid)
+                        boolean xflag = _extraflags >> 3 != ( rs1 & 0x1fffffff );
+                        rval = xflag ? 1 : 0;  // Validate that our reservation slot is OK.
+                        dowrite = !xflag; // Only write if slot is valid.
+                        break;
+                    }
+                    case  0: rs2 += rval; break; // AMOADD.W  (0b00000)
+                    case  1:              break; // AMOSWAP.W (0b00001)
+                    case  4: rs2 ^= rval; break; // AMOXOR.W  (0b00100)
+                    case  8: rs2 |= rval; break; // AMOOR.W   (0b01000)
+                    case 12: rs2 &= rval; break; // AMOAND.W  (0b01100)
+                    case 16: rs2 = Math.min( rs2, rval ); break; //AMOMIN.W (0b10000)
+                    case 20: rs2 = Math.max( rs2, rval ); break; //AMOMAX.W (0b10100)
+                    case 24: rs2 = Math.min( rs2, rval ); break; //AMOMINU.W (0b11000)
+                    case 28: rs2 = Math.max( rs2, rval ); break; //AMOMAXU.W (0b11100)
+                    default: trap = (2+1); dowrite = false; break; //Not supported.
+                    }
+                    if( dowrite ) st4( (int)rs1, (int)rs2 );
+                }
+                break;
+            }
+
+            case 0x53: {
+                is_f = true;
+                int rs1  = (ir >> 15) & 0x1F;
+                int rs2  = (ir >> 20) & 0x1F;
+                double lhs = fregs[rs1];
+                double rhs = fregs[rs2];
+                int func5 = (ir >> 27) & 0x1F;
+                int func2 = (ir >> 25) & 0x3;
+                if( func2 != 1 ) throw Utils.TODO(); // 1==double
+                switch( func5 ) {
+                case  0:  frval = lhs + rhs;  break;  // fadd.d
+                case  1:  frval = lhs - rhs;  break;  // fsub.d
+                case  2:  frval = lhs * rhs;  break;  // fmul.d
+                case  3:  frval = lhs / rhs;  break;  // fdiv.d
+                case  5:  frval = Math.min(lhs,rhs); break; // fmin.d, also used for move
+                case 20:
+                    is_f = false; // Output into a GPR
+                    rval = switch( (ir >> 12) & 7 ) {
+                    case 0 -> lhs <= rhs ? 1 : 0;
+                    case 1 -> lhs == rhs ? 1 : 0;
+                    case 2 -> lhs <  rhs ? 1 : 0;
+                    default -> throw Utils.TODO();
+                    };
+                    break;
+                case 26:  frval = (double)regs[rs1]; break; // fcvt.w.d
+                default:
+                    trap  = (2+1); // Fault: Invalid opcode.
+                    throw Utils.TODO();
+                }
+                break;
+            }
+
+            default: trap = (2+1); // Fault: Invalid opcode.
+            }
+
+            // If there was a trap, do NOT allow register writeback.
+            if( trap!=0 ) {
+                _pc = pc;
+                break;
+            }
+
+            if( rdid!=0 || is_f) {
+                if(is_f) {fregs[rdid] = frval; is_f = false;} // Write back register.
+                else regs[rdid] = rval; // Write back register.
+            }
+
+            pc += 4;
+        }
+
+        // Handle traps and interrupts.
+        if( trap!=0 )
+            return trap;
+
+        _cycle = cycle;
+        _pc = pc;
+        return 0;
+    }
+}
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/FuzzerWrap.java b/chapter22/src/test/java/com/seaofnodes/simple/FuzzerWrap.java
new file mode 100644
index 00000000..d67b2065
--- /dev/null
+++ b/chapter22/src/test/java/com/seaofnodes/simple/FuzzerWrap.java
@@ -0,0 +1,43 @@
+package com.seaofnodes.simple;
+
+import com.seaofnodes.simple.fuzzer.Fuzzer;
+import java.util.Random;
+import org.junit.Ignore;
+import org.junit.Test;
+import static org.junit.Assert.assertTrue;
+
+/**
+ * To use the fuzzer run the <code>fuzzPeeps</code> methods.
+ * This can be done from IntelliJ Gui or remove the `@Ignore` annotation and start the test case from the command line
+ * via <code>mvn clean test -Dtest=com.seaofnodes.simple.Fuzzer08Test#fuzzPeeps</code>
+ */
+public class FuzzerWrap {
+
+    @Ignore
+    @Test
+    public void fuzzPeeps() {
+        var fuzzer = new Fuzzer();
+        for (int i=0; i<1000000; i++)
+            fuzzer.fuzzPeeps(i);
+        assertTrue(fuzzer.noExceptions());
+    }
+
+
+    @Test
+    public void fuzzPeepsSmall() {
+        Random R = new Random(System.currentTimeMillis());
+        var fuzzer = new Fuzzer();
+        for (int i=0; i<100; i++)
+            fuzzer.fuzzPeeps( R.nextLong());
+        assertTrue(fuzzer.noExceptions());
+    }
+
+    @Test
+    @Ignore
+    public void fuzzPeepTiming() {
+        var fuzzer = new Fuzzer();
+        int max_nid=0;
+        for (int i=0; i<1000000; i++)
+            max_nid = fuzzer.fuzzPeepTiming(i, max_nid);
+    }
+}
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/Main.java b/chapter22/src/test/java/com/seaofnodes/simple/Main.java
new file mode 100644
index 00000000..589c043b
--- /dev/null
+++ b/chapter22/src/test/java/com/seaofnodes/simple/Main.java
@@ -0,0 +1,18 @@
+package com.seaofnodes.simple;
+
+import com.seaofnodes.simple.codegen.CodeGen;
+import java.nio.file.Files;
+import java.nio.file.Path;
+
+public class Main {
+    // Compile and run a simple program
+    public static void main( String[] args ) throws Exception {
+        // First arg is file, 2nd+ args are program args
+        String src = Files.readString(Path.of(args[0]));
+        int arg = Integer.valueOf(args[1]);
+        CodeGen code = new CodeGen(src);
+        code.parse().opto().typeCheck().GCM().localSched();
+        System.out.println(code._stop);
+        System.out.println(Eval2.eval(code,arg,100000));
+    }
+}
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/MergeSortTest.java b/chapter22/src/test/java/com/seaofnodes/simple/MergeSortTest.java
new file mode 100644
index 00000000..a1004fb5
--- /dev/null
+++ b/chapter22/src/test/java/com/seaofnodes/simple/MergeSortTest.java
@@ -0,0 +1,44 @@
+package com.seaofnodes.simple;
+
+import com.seaofnodes.simple.codegen.CodeGen;
+import com.seaofnodes.simple.node.cpus.riscv.riscv;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import org.junit.Test;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.fail;
+
+public class MergeSortTest {
+
+    @Test public void testMergeSort0() throws IOException {
+        int[] primes = new int[] { 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, };
+        SB sb = new SB().p(primes.length).p("[");
+        for( int prime : primes )
+            sb.p(prime).p(", ");
+        String sprimes = sb.p("]").toString();
+        TestC.run("sort", sprimes, 40);
+
+
+        EvalRisc5 R5 = TestRisc5.build("src/test/java/com/seaofnodes/simple/progs", "sort", "merge_sort", 0, 36, false);
+        // Allocate an array of primes, filled in reverse order
+        int ps = R5._heap;
+        R5._heap += (primes.length+1)*8; // 25 primes, and length
+        R5.st4(ps,primes.length);
+        for( int i=0; i<primes.length; i++ )
+            R5.st8(ps+(primes.length-1-i+1)*8,primes[i]);
+        // Pass array base when calling `merge_sort`
+        R5.regs[riscv.A0] = ps;          // Array base to be sorted
+
+        int trap = R5.step(100000);
+        assertEquals(0,trap);
+
+        assertEquals(primes.length,R5.ld4s(ps));
+        for( int i=0; i<primes.length; i++ )
+            assertEquals(primes[i], R5.ld8(ps+(i+1)*8));
+
+        // TODO: replace with ARM Eval
+        String src = Files.readString(Path.of("src/test/java/com/seaofnodes/simple/progs/sort.smp"));
+        Chapter21Test.testCPU(src,"arm", "SystemV",36,null);
+    }
+}
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/SchedulerTest.java b/chapter22/src/test/java/com/seaofnodes/simple/SchedulerTest.java
new file mode 100644
index 00000000..ca29bf84
--- /dev/null
+++ b/chapter22/src/test/java/com/seaofnodes/simple/SchedulerTest.java
@@ -0,0 +1,74 @@
+package com.seaofnodes.simple;
+
+import com.seaofnodes.simple.codegen.CodeGen;
+import com.seaofnodes.simple.evaluator.Evaluator;
+import com.seaofnodes.simple.node.StopNode;
+import org.junit.Assert;
+import org.junit.Ignore;
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+
+public class SchedulerTest {
+
+    private static void assertObj(Object obj, String name, Object... fields) {
+        assertEquals(Evaluator.Obj.class, obj.getClass());
+        var o = (Evaluator.Obj)obj;
+        assertEquals(name, o.struct()._name);
+        Assert.assertArrayEquals(fields, o.fields());
+    }
+
+    @Test
+    @Ignore
+    public void testJig() {
+        CodeGen code = new CodeGen("""
+struct S {
+    int f;
+}
+S !v=new S;
+v.f = 2;
+int i=v.f;
+if (arg) v.f=1;
+return i;
+""");
+        code.parse();//.opto();
+        var eval = new Evaluator(code._stop);
+        assertEquals(2L, eval.evaluate(1, 10));
+    }
+
+    @Test
+    public void testStoreInIf() {
+        CodeGen code = new CodeGen("""
+struct S {
+    int f;
+};
+S !v0=new S;
+if(arg) v0.f=1;
+return v0;
+""");
+        code.parse().opto();
+        var eval = new Evaluator(code._stop);
+        assertObj(eval.evaluate(0, 10), "S", 0L);
+        assertObj(eval.evaluate(1, 10), "S", 1L);
+    }
+
+    @Test
+    public void testStoreInIf2() {
+        CodeGen code = new CodeGen("""
+struct S {
+    int f;
+};
+S !v=new S;
+v.f = 2;
+int i=new S.f;
+i=v.f;
+if (arg) v.f=1;
+return i;
+""");
+        code.parse().opto();
+        var eval = new Evaluator(code._stop);
+        assertEquals(2L, eval.evaluate(0, 10));
+        assertEquals(2L, eval.evaluate(1, 10));
+    }
+
+}
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/Simple.java b/chapter22/src/test/java/com/seaofnodes/simple/Simple.java
new file mode 100644
index 00000000..9b1e2827
--- /dev/null
+++ b/chapter22/src/test/java/com/seaofnodes/simple/Simple.java
@@ -0,0 +1,313 @@
+package com.seaofnodes.simple;
+
+import com.seaofnodes.simple.codegen.CodeGen;
+import com.seaofnodes.simple.print.*;
+
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.io.InputStreamReader;
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.util.stream.Collectors;
+
+public class Simple {
+    public static final String PORTS = "com.seaofnodes.simple.node.cpus";
+
+    static final int DUMP_AFTER_PARSE        = 1<<0;
+    static final int DUMP_AFTER_OPTO         = 1<<1;
+    static final int DUMP_AFTER_TYPE_CHECK   = 1<<2;
+    static final int DUMP_AFTER_LOOP_TREE    = 1<<3;
+    static final int DUMP_AFTER_INSTR_SELECT = 1<<4;
+    static final int DUMP_AFTER_GCM          = 1<<5;
+    static final int DUMP_AFTER_LOCAL_SCHED  = 1<<6;
+    static final int DUMP_AFTER_REG_ALLOC    = 1<<7;
+    static final int DUMP_AFTER_ENCODE       = 1<<8;
+
+    static final int DUMP_FINAL              = 1<<16;
+
+    static final int DUMP_DOT                = 1<<29;
+    static final int DUMP_PASS_NAME          = 1<<30;
+    static final int DUMP_AFTER_ALL          = 0xff | DUMP_PASS_NAME;
+    static final int DUMP_DOT_AFTER_ALL      = 0xff | DUMP_DOT;
+
+    static final int DUMP_DISASSEMBLE        = 1<<31;
+
+    static String system_cpu = null;
+    static String system_abi = null;
+
+    static void usage() {
+        System.out.println(
+"""
+simple <input-file> [options] [--eval|--run ...]
+Options:
+  --dump                     - dump final intermediate representation
+  --dump-after-parse         - dump intermediate representation after parse
+  --dump-after-opto          - dump intermediate representation after opto pass
+  --dump-after-type-check    - dump intermediate representation after type check pass
+  --dump-after-instr-select  - dump intermediate representation after instrution selection pass
+  --dump-after-gcm           - dump intermediate representation after GCM pass
+  --dump-after-local-sched   - dump intermediate representation after local scheduling pass
+  --dump-after-reg-alloc     - dump intermediate representation after register allocation pass
+  --dump-after-encode        - dump intermediate representation after encoding pass
+  --dump-after-all           - dump intermediate representation after all passes
+  --dot                      - dump grapical representation of intermediate code into *.dot file(s)
+  -S                         - dump generated assembler code
+  --eval ...                 - evaluate the compiled code in emulator
+  --run ...                  - run the compiled code natively
+  --dump-size                - print the size of generated code
+  --dump-time                - print compilation and execution times
+  --cpu <cpu-name>           - use specific CPU (x86_64_v2, riscv, arm)
+  --abi <abi-name>           - use speific ABI variant (SystemV)
+  --target                   - print native CPU and ABI
+  --version
+  --help
+"""
+);
+        System.exit(0);
+    }
+
+    static void bad_usage() {
+        System.err.println("ERROR: Invalid usage (use --help)");
+        System.exit(1);
+    }
+
+    static void target() {
+        if (system_cpu == null || system_abi == null) {
+            System.err.println("ERROR: Unknown target");
+            System.exit(1);
+        }
+        System.out.print(system_cpu);
+        System.out.print("-");
+        System.out.println(system_abi);
+        System.exit(0);
+    }
+
+    static void dump(CodeGen code, int dump, int pass) {
+        if ((dump & pass) != 0) {
+            if ((dump & DUMP_DOT) != 0) {
+                String fn = switch (pass) {
+                    case DUMP_AFTER_PARSE        -> "01-parse.dot";
+                    case DUMP_AFTER_OPTO         -> "02-opto.dot";
+                    case DUMP_AFTER_TYPE_CHECK   -> "03-type_check.dot";
+                    case DUMP_AFTER_LOOP_TREE    -> "04-loop_tree.dot";
+                    case DUMP_AFTER_INSTR_SELECT -> "05-instr_select.dot";
+                    case DUMP_AFTER_GCM          -> "06-gcm.dot";
+                    case DUMP_AFTER_LOCAL_SCHED  -> "07-local_sched.dot";
+                    case DUMP_AFTER_REG_ALLOC    -> "08-reg_allos.dot";
+                    case DUMP_AFTER_ENCODE       -> "09-local_sched.dot";
+                    case DUMP_FINAL              -> "10-final.dot";
+                    default                      -> throw Utils.TODO();
+                };
+
+                try {
+                    Files.writeString(Path.of(fn),
+                        new GraphVisualizer().generateDotOutput(code._stop, null, null));
+                } catch(IOException e) {
+                    System.err.println("ERROR: Cannot write DOT file");
+                    System.exit(1);
+                }
+            } else {
+                if ((dump & DUMP_PASS_NAME) != 0) {
+                    System.err.println(switch (pass) {
+                        case DUMP_AFTER_PARSE        -> "After Parse:";
+                        case DUMP_AFTER_OPTO         -> "After OPTO:";
+                        case DUMP_AFTER_TYPE_CHECK   -> "After Type Check:";
+                        case DUMP_AFTER_LOOP_TREE    -> "After Loop Tree:";
+                        case DUMP_AFTER_INSTR_SELECT -> "After Instruction Selection:";
+                        case DUMP_AFTER_GCM          -> "After GCM:";
+                        case DUMP_AFTER_LOCAL_SCHED  -> "After Local Scheduling:";
+                        case DUMP_AFTER_REG_ALLOC    -> "After Register Allocation:";
+                        case DUMP_AFTER_ENCODE       -> "After Instruction Encoding:";
+                        case DUMP_FINAL              -> "Final:";
+                        default                      -> throw Utils.TODO();
+                    });
+                }
+
+                System.err.println(IRPrinter.prettyPrint(code._stop, 9999));
+            }
+        }
+    }
+
+    static void print_compilation_times(CodeGen code) {
+        double t, total = 0;
+
+        total += t = code._tParse / 1e3;
+        System.out.println(String.format("Parsing Time:               %.3f sec", t));
+        total += t = code._tOpto / 1e3;
+        System.out.println(String.format("Optimization Time:          %.3f sec", t));
+        total += t = code._tTypeCheck / 1e3;
+        System.out.println(String.format("Type Checking Time:         %.3f sec", t));
+        total += t = code._tLoopTree / 1e3;
+        System.out.println(String.format("Loop Tree Time:             %.3f sec", t));
+        total += t = code._tInsSel / 1e3;
+        System.out.println(String.format("Instruction Selection Time: %.3f sec", t));
+        total += t = code._tGCM / 1e3;
+        System.out.println(String.format("GCM Time:                   %.3f sec", t));
+        total += t = code._tLocal / 1e3;
+        System.out.println(String.format("Local Scheduling Time:      %.3f sec", t));
+        total += t = code._tRegAlloc / 1e3;
+        System.out.println(String.format("Register Allocation Time:   %.3f sec", t));
+        total += t = code._tEncode / 1e3;
+        System.out.println(String.format("Instruction Encoding Time:  %.3f sec", t));
+        System.out.println(String.format("TOTAL COMPILATION TIME:     %.3f sec", total));
+    }
+
+    static String getInput() {
+        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
+        return reader.lines().collect(Collectors.joining("\n"));
+    }
+
+    public static void main(String[] args) throws Exception {
+        String input_filename = null;
+        boolean use_stdin = false;
+        boolean do_eval = false;
+        boolean do_run = false;
+        boolean do_codegen = false;
+        boolean do_print_size = false;
+        boolean do_print_time = false;
+        int dump = 0;
+        int first_arg = 0;
+        String src = null;
+        String cpu = null;
+        String abi = null;
+
+        // TODO: autodetect
+        system_cpu = "x86_64_v2";
+        system_abi = "SystemV";
+
+        // Parse command line
+loop:   for (int i = 0; i < args.length; i++) {
+            String arg = args[i];
+            if (arg.charAt(0) == '-') {
+                switch (arg) {
+                    case "-":                         use_stdin = true; break;
+                    case "--dump":                    dump |= DUMP_FINAL; break;
+                    case "--dump-after-parse":        dump |= DUMP_AFTER_PARSE; break;
+                    case "--dump-after-opto":         dump |= DUMP_AFTER_OPTO; break;
+                    case "--dump-after-type-check":   dump |= DUMP_AFTER_TYPE_CHECK; break;
+                    case "--dump-after-loop-tree":    dump |= DUMP_AFTER_LOOP_TREE; break;
+                    case "--dump-after-instr-select": dump |= DUMP_AFTER_INSTR_SELECT; break;
+                    case "--dump-after-gcm":          dump |= DUMP_AFTER_GCM; break;
+                    case "--dump-after-local-sched":  dump |= DUMP_AFTER_LOCAL_SCHED; break;
+                    case "--dump-after-reg-alloc":    dump |= DUMP_AFTER_REG_ALLOC; break;
+                    case "--dump-after-encode":       dump |= DUMP_AFTER_ENCODE; break;
+                    case "--dump-after-all":          dump |= DUMP_AFTER_ALL; break;
+                    case "--dot":                     dump |= DUMP_DOT; break;
+                    case "-S":                        dump |= DUMP_DISASSEMBLE; break;
+                    case "--eval":                    do_eval = true; first_arg = i + 1; break loop;
+                    case "--run":                     do_run = true; first_arg = i + 1; break loop;
+                    case "--dump-size":               do_print_size = true; break;
+                    case "--dump-time":               do_print_time = true; break;
+                    case "--cpu":                     if (cpu != null
+                                                       || i + 1 >= args.length
+                                                       || args[i + 1].charAt(0) == '-') bad_usage();
+                                                      cpu = args[i + 1];
+                                                      i++;
+                                                      break;
+                    case "--abi":                     if (abi != null
+                                                       || i + 1 >= args.length
+                                                       || args[i + 1].charAt(0) == '-') bad_usage();
+                                                      abi = args[i + 1];
+                                                      i++;
+                                                      break;
+                    case "--target":                  target();
+                    case "--version":                 throw Utils.TODO();
+                    case "--help":                    usage();
+                    default:                          bad_usage();
+                }
+            } else {
+                if (input_filename != null || use_stdin) bad_usage();
+                input_filename = arg;
+            }
+        }
+
+        if (input_filename == null && !use_stdin) {
+            System.err.println("ERROR: no input file' (use --help)");
+            System.exit(1);
+        }
+
+        if (do_run || (dump & DUMP_DISASSEMBLE) != 0 || do_print_size) {
+            if (cpu == null) cpu = system_cpu;
+            if (abi == null) abi = system_abi;
+            if (cpu == null || abi == null) {
+                System.err.println("ERROR: Cannot compile for unknown target");
+                System.exit(1);
+            }
+            do_codegen = true;
+        }
+
+        // Read input file
+        try {
+            src = use_stdin ? getInput() : Files.readString(Path.of(input_filename));
+        } catch(IOException e) {
+            System.err.println("ERROR: Cannot read input file");
+            System.exit(1);
+        }
+
+        // Compilation pipeline
+        CodeGen code = new CodeGen(src);
+
+        code.parse();
+        dump(code, dump, DUMP_AFTER_PARSE);
+
+        code.opto();
+        dump(code, dump, DUMP_AFTER_OPTO);
+
+        code.typeCheck();
+        dump(code, dump, DUMP_AFTER_TYPE_CHECK);
+
+        code.loopTree();
+        dump(code, dump, DUMP_AFTER_LOOP_TREE);
+
+        if (do_codegen) {
+            code.instSelect(PORTS, cpu, abi);
+            dump(code, dump, DUMP_AFTER_INSTR_SELECT);
+        }
+
+        code.GCM();
+        dump(code, dump, DUMP_AFTER_GCM);
+
+        code.localSched();
+        dump(code, dump, DUMP_AFTER_LOCAL_SCHED);
+
+        if (do_codegen) {
+            code.regAlloc();
+            dump(code, dump, DUMP_AFTER_REG_ALLOC);
+
+            code.encode();
+            dump(code, dump, DUMP_AFTER_ENCODE);
+        }
+
+        dump(code, dump, DUMP_FINAL);
+
+        if (do_codegen && (dump & DUMP_DISASSEMBLE) != 0) {
+            System.out.println(code.asm());
+        }
+
+        if (do_print_size) {
+             System.out.println(String.format("Code Size: %d", code._encoding._bits.size()));
+        }
+
+        if (do_print_time) {
+            print_compilation_times(code);
+        }
+
+        if (do_eval) {
+            // TODO: Support for evaluation of functions with different argument numbers and types
+            long t = System.currentTimeMillis();
+            long arg = (first_arg < args.length) ? Integer.valueOf(args[first_arg]) : 0;
+            System.out.println(Eval2.eval(code, arg, 100000));
+            if (do_print_time) {
+                System.out.println(String.format("EXECUTION TIME:             %.3f sec",
+                    (System.currentTimeMillis() - t) / 1e3));
+            }
+        } else if (do_run) {
+            if (cpu != system_cpu || abi != system_abi) {
+                System.err.println("ERROR: cannot run code on not native target");
+                System.exit(1);
+            }
+
+            throw Utils.TODO();
+        }
+    }
+}
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/TestArm64.java b/chapter22/src/test/java/com/seaofnodes/simple/TestArm64.java
new file mode 100644
index 00000000..739f5b1e
--- /dev/null
+++ b/chapter22/src/test/java/com/seaofnodes/simple/TestArm64.java
@@ -0,0 +1,42 @@
+package com.seaofnodes.simple;
+
+
+import com.seaofnodes.simple.codegen.CodeGen;
+import com.seaofnodes.simple.node.cpus.arm.arm;
+import junit.framework.Assert;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.io.IOException;
+
+import static org.junit.Assert.assertEquals;
+
+// Runs 32-bit ARM code in an emulator
+
+public class TestArm64 {
+    public static EvalArm64 build(String file, int arg, int spills, boolean print) throws IOException {
+        return  build("src/test/java/com/seaofnodes/simple/progs",file, arg, spills, print);
+    }
+
+    // Compile and run a simple program
+    public static EvalArm64 build(String dir, String file, int arg, int spills, boolean print) throws IOException {
+        // Compile and export Simple
+        String src = Files.readString(Path.of(dir+"/"+file+".smp"));
+        CodeGen code = new CodeGen(src).driver("arm", "SystemV",null);
+        if(print) {code.print_as_hex(); System.out.print(code.asm());}
+
+        // Allocation quality not degraded
+        int delta = spills>>3;
+        if(delta == 0) delta =1;
+        if(spills != -1) assertEquals("Expect spills:", spills, code._regAlloc._spillScaled, delta);
+
+        // Image
+        byte[] image = new byte[1<<20]; // A megabyte (1024*1024 bytes)
+        EvalArm64 ARM = new EvalArm64(image, 1<<16);
+        // Code at offset 0
+        System.arraycopy(code._encoding.bits(), 0, image, 0, code._encoding.bits().length);
+        // Initial incoming int arg
+        ARM.regs[arm.X0] = arg;
+        // malloc memory starts at 64K and goes up
+        return ARM;
+    }
+}
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/TestC.java b/chapter22/src/test/java/com/seaofnodes/simple/TestC.java
new file mode 100644
index 00000000..5609758b
--- /dev/null
+++ b/chapter22/src/test/java/com/seaofnodes/simple/TestC.java
@@ -0,0 +1,89 @@
+package com.seaofnodes.simple;
+
+import com.seaofnodes.simple.codegen.CodeGen;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.io.InputStream;
+import java.io.IOException;
+import static org.junit.Assert.*;
+
+// Call a C driver program, which calls a Simple-generated .o, and self-checks.
+// Expects GCC from the default CLI, compiles C, compiles Simple, links and runs.
+public abstract class TestC {
+
+    public static final String OS  = System.getProperty("os.name");
+    public static final String CPU = System.getProperty("os.arch");
+
+    public static final String CALL_CONVENTION = OS.startsWith("Windows") ? "Win64" : "SystemV";
+    public static final String CPU_PORT = switch( CPU ) {
+    case "amd64" -> "x86_64_v2";
+    default -> throw Utils.TODO("Map Yer CPU Port Here");
+    };
+
+    public static void run( String file, int spills ) throws IOException { run(file,"",spills); }
+
+    public static void run( String file, String expected, int spills ) throws IOException {
+        run("src/test/java/com/seaofnodes/simple/progs",file,expected,spills);
+    }
+
+    // Compile and run a simple program
+    public static void run( String dir, String file, String expected, int spills ) throws IOException {
+        // Files
+        String  cfile = dir+"/"+file+".c"  ;
+        String  sfile = dir+"/"+file+".smp";
+        String  efile = "build/objs/"+file;
+
+        // Compile and export Simple
+        String src = Files.readString(Path.of(sfile));
+        _run(src,CALL_CONVENTION,"",cfile,efile,"S",expected,spills);
+    }
+
+    static void _run( String src, String simple_conv, String c_conv, String cfile, String efile, String xtn, String expected, int spills ) throws IOException {
+        String bin = efile+xtn;
+        String obj = bin+".o";
+        // Compile simple, emit ELF
+        CodeGen code = new CodeGen(src).driver( CPU_PORT, simple_conv, obj);
+
+        // Compile the C program
+        var params = new String[] {
+            //if (USE_WSL) "wsl.exe";
+            "gcc",
+            cfile,
+            obj,
+            "-lm", // Picks up 'sqrt' for newtonFloat tests to compare
+            "-g",
+            "-o",
+            bin,
+            "-D",
+            "CALL_CONV="+c_conv,
+        };
+        Process gcc = new ProcessBuilder(params).redirectErrorStream(true).start();
+        byte error;
+        try { error = (byte)gcc.waitFor(); } catch( InterruptedException e ) { throw new IOException("interrupted"); }
+        String result = new String(gcc.getInputStream().readAllBytes());
+        if( error!=0 ) {
+            System.err.println("gcc error code: "+error);
+            System.err.println(result);
+        }
+        assertEquals( 0, error );
+        //assertTrue(result.isEmpty()); // No data in error stream
+
+        // Execute results
+        Process smp = new ProcessBuilder(bin).redirectErrorStream(true).start();
+        try { error = (byte)smp.waitFor(); } catch( InterruptedException e ) { throw new IOException("interrupted"); }
+        result = new String(smp.getInputStream().readAllBytes());
+        if( error!=0 ) {
+            System.err.println("exec error code: "+error);
+            System.err.println(result);
+        }
+        assertEquals( 0, error );
+        assertEquals(expected,result);
+
+        // Allocation quality not degraded
+        int delta = spills>>3;
+        if( delta==0 ) delta = 1;
+        if( spills != -1 )
+            assertEquals("Expect spills:",spills,code._regAlloc._spillScaled,delta);
+
+    }
+}
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/TestRisc5.java b/chapter22/src/test/java/com/seaofnodes/simple/TestRisc5.java
new file mode 100644
index 00000000..b7642540
--- /dev/null
+++ b/chapter22/src/test/java/com/seaofnodes/simple/TestRisc5.java
@@ -0,0 +1,50 @@
+package com.seaofnodes.simple;
+
+import com.seaofnodes.simple.codegen.CodeGen;
+import com.seaofnodes.simple.node.FunNode;
+import com.seaofnodes.simple.node.Node;
+import com.seaofnodes.simple.node.cpus.riscv.riscv;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import static org.junit.Assert.*;
+
+// Runs 32-bit R5 code in an emulator
+public abstract class TestRisc5 {
+
+    public static EvalRisc5 build( String file, int arg, int spills, boolean print) throws IOException {
+        return build("src/test/java/com/seaofnodes/simple/progs",file, null, arg, spills, print);
+    }
+
+    // Compile and run a simple program
+    public static EvalRisc5 build( String dir, String file, String main, int arg, int spills, boolean print) throws IOException {
+        // Compile and export Simple
+        String src = Files.readString(Path.of(dir+"/"+file+".smp"));
+        CodeGen code = new CodeGen(src).driver("riscv", "SystemV",null);
+        if(print) {code.print_as_hex(); System.out.print(code.asm());}
+
+        // Allocation quality not degraded
+        int delta = spills>>3;
+        if( delta==0 ) delta = 1;
+        if( spills != -1 )
+            assertEquals("Expect spills:",spills,code._regAlloc._spillScaled,delta);
+
+        // Image
+        byte[] image = new byte[1<<20]; // A megabyte (1024*1024 bytes)
+        EvalRisc5 R5 = new EvalRisc5(image, 1<<16);
+        // Code at offset 0
+        System.arraycopy(code._encoding.bits(), 0, image, 0, code._encoding.bits().length);
+        // Initial incoming int arg
+        R5.regs[riscv.A0] = arg;
+        // malloc memory starts at 64K and goes up
+
+        // Look up starting PC or zero if not given
+        if( main!=null )
+            for( Node use : code._start._outputs )
+                if( use instanceof FunNode fun && main.equals(fun._name) )
+                    R5._pc = code._encoding._opStart[fun._nid];
+
+        return R5;
+    }
+
+}
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/TypeTest.java b/chapter22/src/test/java/com/seaofnodes/simple/TypeTest.java
new file mode 100644
index 00000000..d94f5b5a
--- /dev/null
+++ b/chapter22/src/test/java/com/seaofnodes/simple/TypeTest.java
@@ -0,0 +1,158 @@
+package com.seaofnodes.simple;
+
+import com.seaofnodes.simple.type.*;
+import org.junit.Assert;
+import org.junit.Test;
+import static org.junit.Assert.assertSame;
+
+public class TypeTest {
+
+    // Test basic properties and GLB
+    @Test
+    public void testTypeAdHoc() {
+        Assert.assertEquals( Type.BOTTOM, TypeInteger.TRUE.meet(TypeNil.NIL) );
+        Assert.assertEquals( Type.BOTTOM, TypeInteger.TOP.meet(TypeNil.NIL) );
+
+
+        TypeStruct s1 = TypeStruct.make("s1", new Field[]{
+                Field.make("a", TypeInteger.BOT,-1, false),
+                Field.make("b", TypeInteger.BOT,-2, false) });
+        TypeStruct s2 = TypeStruct.make("s2", new Field[]{
+                Field.make("a", TypeInteger.BOT,-3, false),
+                Field.make("b", TypeInteger.BOT,-4, false) });
+        Assert.assertEquals(s1.makeRO(), s1.glb());
+        Assert.assertNotEquals(s1, s1.dual());
+        Assert.assertEquals(s1.makeRO(), s1.dual().glb());
+
+        TypeMem m1 = TypeMem.make(1,TypeNil.NIL);
+        TypeMem m2 = TypeMem.make(2,TypeInteger.U16);
+        TypeMem m3 = TypeMem.make(3,TypeFloat.F64);
+        TypeMem m4 = TypeMem.make(4,TypeInteger.BOT);
+
+        Assert.assertNotEquals(m1, m2);
+        Assert.assertNotEquals(m2, m3);
+        Assert.assertNotEquals(m3, m4);
+
+        Assert.assertEquals(TypeStruct.BOT, s1.meet(s2));
+        Assert.assertEquals(TypeMem   .BOT, m1.meet(m2));
+        Assert.assertEquals(TypeMem.make(0,Type.BOTTOM), m1.meet(m3));
+        Assert.assertEquals(TypeMem   .BOT, m3.meet(m4));
+
+        Assert.assertEquals(TypeMem.make(1,Type.BOTTOM), m1.glb());
+        Assert.assertEquals(TypeMem.make(1,Type.XNIL), m1.dual());
+        Assert.assertEquals(m4.dual(), m4.glb().dual());
+
+        TypeMemPtr ptr1 = TypeMemPtr.make(s1);
+        Assert.assertEquals(s1, ptr1._obj);
+        TypeMemPtr ptr2 = TypeMemPtr.make(s2);
+        Assert.assertEquals(s2, ptr2._obj);
+
+        TypeMemPtr ptr1nil = TypeMemPtr.makeNullable(s1);
+        Assert.assertEquals(s1, ptr1nil._obj);
+        Assert.assertTrue( ptr1nil.nullable() );
+        Assert.assertNotNull( ptr1nil._obj );
+        TypeMemPtr ptr2nil = TypeMemPtr.makeNullable( s2);
+        Assert.assertEquals(s2, ptr2nil._obj);
+
+        Assert.assertNotEquals(ptr1, ptr2);
+        Assert.assertNotEquals(ptr1, ptr1.glb());
+        Assert.assertEquals(ptr1nil.makeRO(), ptr1.glb());
+
+        Assert.assertEquals(ptr1, ptr1.dual().dual());
+        Assert.assertEquals(ptr1.glb().makeRO(), ptr1.dual().glb());
+        Assert.assertEquals(TypeMemPtr.makeNullable(TypeStruct.BOT), ptr1.meet(ptr2nil));
+        Assert.assertEquals(ptr1.glb(), ptr1.meet(TypeNil.NIL).makeRO());
+
+        TypeMemPtr TOP = TypeMemPtr.TOP;
+        TypeMemPtr BOT = TypeMemPtr.makeNullable(TypeStruct.BOT);
+        TypeMemPtr PTR = TypeMemPtr.make(TypeStruct.BOT);
+        Type NULL = TypeNil.NIL;
+        Type PTR_meet_NULL = NULL.meet(PTR);
+        Assert.assertEquals(BOT, PTR_meet_NULL);
+        Type ptr1_meet_ptr2 = ptr1.meet(ptr2);
+        Assert.assertEquals(PTR, ptr1_meet_ptr2);
+        Type NULL_join_ptr1 = NULL.join(ptr1);
+        Assert.assertEquals(TypePtr.XNPTR, NULL_join_ptr1);
+        Type NULL_join_PTR = PTR.join(NULL);
+        Assert.assertEquals(TypePtr.XNPTR, NULL_join_PTR);
+        Type ptr1_dual = ptr1.dual();
+        Type nullableptr1_dual = ptr1nil.dual();
+    }
+
+    // Test theoretical properties.
+    // This is a symmetric complete bounded (ranked) lattice.
+    // Also, the meet is commutative and associative.
+    // The lattice has a dual (symmetric), and join is ~(~x meet ~y).
+    // See https://en.wikipedia.org/wiki/Lattice_(order).
+    @Test
+    public void testLatticeTheory() {
+        Type[] ts = Type.gather();
+
+        // Confirm commutative & complete
+        for( Type t0 : ts )
+            for( Type t1 : ts ) {
+                check_commute  (t0,t1);
+                check_symmetric(t0,t1);
+            }
+
+        // Confirm associative
+        for( Type t0 : ts )
+            for( Type t1 : ts )
+                for( Type t2 : ts )
+                    assoc(t0,t1,t2);
+
+        // Confirm symmetry.  If A isa B, then A.join(C) isa B.join(C)
+        for( Type t0 : ts )
+            for( Type t1 : ts )
+                if( t0.isa(t1) )
+                    for( Type t2 : ts ) {
+                        Type t02 = t0.join(t2);
+                        Type t12 = t1.join(t2);
+                        Type mt  = t02.meet(t12);
+                        assertSame(mt,t12);
+                    }
+    }
+
+    // By design in meet, args are already flipped to order _type, which forces
+    // symmetry for things with badly ordered _type fields.  The question is
+    // still interesting for other orders.
+    private static void check_commute( Type t0, Type t1 ) {
+        if( t0==t1 ) return;
+        if( t0.is_simple() && !t1.is_simple() ) return; // By design, flipped the only allowed order
+        Type mta = t0.meet(t1);
+        Type mtb = t1.meet(t0); // Reverse args and try again
+        assertSame(mta,mtb);
+    }
+
+    // A & B = MT
+    // Expect: ~A & ~MT == ~A
+    // Expect: ~B & ~MT == ~B
+    private static void check_symmetric( Type t0, Type t1 ) {
+        if( t1==t0 ) return;
+        Type mt = t0.meet(t1);
+        Type dm = mt.dual();
+        Type d0 = t0.dual();
+        Type d1 = t1.dual();
+        Type ta = dm.meet(d1);
+        Type tb = dm.meet(d0);
+        assertSame(ta,d1);
+        assertSame(tb,d0);
+    }
+
+    private static void assoc( Type t0, Type t1, Type t2 ) {
+        Type t01   = t0 .meet(t1 );
+        Type t12   = t1 .meet(t2 );
+        Type t01_2 = t01.meet(t2 );
+        Type t0_12 = t0 .meet(t12);
+        assertSame(t01_2,t0_12);
+    }
+
+    // Test cyclic types and meets
+    @Test
+    public void testCyclic0() {
+        Type d0 = TypeStruct.S1.dual();
+        Type d1 = d0.dual();
+        assertSame(TypeStruct.S1,d1);
+    }
+
+}
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/evaluator/Evaluator.java b/chapter22/src/test/java/com/seaofnodes/simple/evaluator/Evaluator.java
new file mode 100644
index 00000000..a3b87e90
--- /dev/null
+++ b/chapter22/src/test/java/com/seaofnodes/simple/evaluator/Evaluator.java
@@ -0,0 +1,383 @@
+package com.seaofnodes.simple.evaluator;
+
+import com.seaofnodes.simple.Utils;
+import com.seaofnodes.simple.node.*;
+import com.seaofnodes.simple.type.*;
+
+import java.util.*;
+
+public class Evaluator {
+
+    private static final Object MEMORY = new Object();
+
+    public record Obj(TypeStruct struct, Object[] fields) {
+        private void init(IdentityHashMap<Obj, Integer> objs) {
+            var oid = objs.get(this);
+            if (oid != null) {
+                if (oid != 0) objs.put(this, 0);
+                return;
+            }
+            objs.put(this, -1);
+            for (var obj : fields) {
+                if (obj instanceof Obj o) o.init(objs);
+            }
+        }
+        private static int p(StringBuilder sb, IdentityHashMap<Obj, Integer> objs, int id, String indentation, String step, String sep, Object obj) {
+            if (obj instanceof Obj o) return o.p(sb, objs, id, indentation, step, sep);
+            sb.append(obj);
+            return id;
+        }
+        private int p(StringBuilder sb, IdentityHashMap<Obj, Integer> objs, int id, String indentation, String step, String sep) {
+            var cid = objs.get(this);
+            assert cid != null;
+            if (cid > 0) {
+                sb.append("obj@").append(cid);
+                return id;
+            }
+            if (struct._name.equals("[u8]")) {
+                sb.append('"');
+                for (int i=struct._fields.length-1; i<fields.length; i++) {
+                    var v = fields[i];
+                    if (v == null) v = 0;
+                    assert v instanceof Number;
+                    var n = ((Number)v).byteValue() & 0xFF;
+                    if (n >= 0x20 && n < 0x80) {
+                        if (n == 0x22 || n == 0x5C) sb.append("\\");
+                        sb.append((char)n);
+                    } else {
+                        sb.append("\\x").append("0123456789abcdef".charAt(n >> 4)).append("0123456789abcdef".charAt(n & 0xF));
+                    }
+                }
+                sb.append('"');
+                return id;
+            }
+            sb.append("Obj<").append(struct._name).append(">");
+            if (cid == 0) {
+                cid = id++;
+                objs.put(this, cid);
+                sb.append("@").append(cid);
+            }
+            sb.append("{");
+            if (struct._fields.length == 0) {
+                assert !struct.isAry();
+                sb.append("}");
+                return id;
+            }
+            String nextIndent = indentation + step;
+            int e = struct._fields.length - 1;
+            for(int i=0; i<e; i++) {
+                sb.append(nextIndent).append(struct._fields[i]._fname).append("=");
+                id = p(sb, objs, id, nextIndent, step, sep, fields[i]);
+                sb.append(sep);
+            }
+            sb.append(nextIndent).append(struct._fields[e]._fname).append("=");
+            if (struct.isAry()) {
+                sb.append("[");
+                if (fields.length > e) {
+                    String innerIndent = nextIndent + step;
+                    sb.append(innerIndent);
+                    id = p(sb, objs, id, nextIndent, step, sep, fields[e]);
+                    for (int i = e+1; i < fields.length; i++) {
+                        sb.append(sep).append(innerIndent);
+                        id = p(sb, objs, id, nextIndent, step, sep, fields[i]);
+                    }
+                    sb.append(nextIndent);
+                }
+                sb.append("]");
+            } else {
+                id = p(sb, objs, id, nextIndent, step, sep, fields[e]);
+            }
+            sb.append(indentation).append("}");
+            return id;
+        }
+        private StringBuilder p(StringBuilder sb, String indentation, String step, String sep) {
+            var objs = new IdentityHashMap<Obj, Integer>();
+            init(objs);
+            p(sb, objs, 1, indentation, step, sep);
+            return sb;
+        }
+        @Override
+        public String toString() {
+            if (struct._name.equals("[u8]")) {
+                var sb = new StringBuilder();
+                for (int i=struct._fields.length-1; i<fields.length; i++) {
+                    var v = fields[i];
+                    if (v == null) v = 0;
+                    assert v instanceof Number;
+                    var n = ((Number)v).byteValue() & 0xFF;
+                    sb.append((char)n);
+                }
+                return sb.toString();
+            }
+            return p(new StringBuilder(), "", "", ",").toString();
+        }
+        public String pretty() {
+            return p(new StringBuilder(), "\n", "  ", "").toString();
+        }
+    }
+
+    private static int getFieldIndex(TypeStruct struct, MemOpNode memop, long off) {
+        int idx = struct.find(memop._name);
+        if( idx >= 0 ) return idx;
+        throw new AssertionError("Field "+memop._name+" not found in struct " + struct._name);
+    }
+
+    public enum Status {
+        TIMEOUT,
+        FALLTHROUGH
+    }
+
+    /**
+     * Find the start node from some node in the graph or null if there is no start node
+     */
+    private static StartNode findStart(BitSet visit, Node node) {
+        if (node == null) return null;
+        if( visit.get(node._nid) ) return null;
+        visit.set(node._nid);
+        StartNode start = node instanceof StartNode ? (StartNode) node : null;
+        for( Node def : node._inputs ) {
+            var res = findStart(visit,def);
+            if( res != null ) start = res;
+        }
+        for( Node use : node._outputs ) {
+            var res = findStart(visit,use);
+            if( res != null ) start = res;
+        }
+        return start;
+    }
+
+    private final Object[] values;
+    private final ArrayList<Object> phiCache = new ArrayList<>();
+    private final StartNode start;
+    private final Scheduler.Block startBlock;
+
+    public Evaluator(Node graph) {
+        var visited = new BitSet();
+        this.start = findStart(visited, graph);
+        if (this.start == null) {
+            this.values = null;
+            this.startBlock = null;
+            return;
+        }
+        this.startBlock = Scheduler.schedule(this.start);
+        this.values = new Object[visited.length()];
+    }
+
+    private long div(DivNode div) {
+        long in2 = vall(div.in(2));
+        return in2 == 0 ? 0 : vall(div.in(1)) / in2;
+    }
+    private double div(DivFNode div) {
+        double in2 = vald(div.in(2));
+        return in2 == 0 ? 0 : vald(div.in(1)) / in2;
+    }
+
+    private static long offToIdx(long off, TypeStruct t) {
+        off -= t.aryBase();
+        int scale = t.aryScale();
+        long mask = (1L << scale)-1;
+        assert (off & mask) == 0;
+        return off>>scale;
+    }
+
+    private Object alloc(NewNode alloc) {
+        TypeStruct type = alloc._ptr._obj;
+        Object[] body=null;
+        int num;
+        if( type.isAry() ) {
+            long sz = (Long)val(alloc.in(1));
+            long n = offToIdx(sz, type);
+            if( n < 0 )
+                throw new NegativeArraySizeException(""+n);
+            body = new Object[(int)n+1]; // Array body
+            var elem = type._fields[1]._type;
+            if (elem instanceof TypeInteger) {
+                for (int i=0; i<n; i++) body[i+1] = 0L;
+            } else if (elem instanceof TypeFloat) {
+                for (int i = 0; i < n; i++) body[i+1] = 0D;
+            } else {
+                assert elem instanceof TypeMemPtr;
+            }
+            // Length value
+            body[0] = vall(alloc.in(2+2));
+        } else {
+            body = new Object[num = type._fields.length];
+            for( int i=0; i<num; i++ )
+                body[i] = switch( alloc._ptr._obj._fields[i]._type ) {
+                case TypeInteger ti -> 0L;
+                case TypeFloat tf -> 0;
+                default -> null;
+                };
+        }
+        Object[] mems = new Object[type._fields.length+2];
+        // mems[0] is control
+        mems[1] = new Obj(type,body); // the ref
+        // mems[2+...] are memory aliases
+        return mems;
+    }
+
+    private Object load(LoadNode load) {
+        var from = (Obj)val(load.ptr());
+        var off = vall(load.off());
+        var idx = getFieldIndex(from.struct, load, (Long)off);
+        if( idx==from.struct._fields.length-1 && from.struct.isAry() ) {
+            long len = from.fields.length - from.struct._fields.length + 1;
+            long i = offToIdx(off, from.struct);
+            if( i < 0 || i >= len )
+                throw new ArrayIndexOutOfBoundsException("Array index out of bounds " + i + " < " + len);
+            return from.fields[(int)i+from.struct._fields.length-1];
+
+        } else
+            return from.fields[idx];
+    }
+
+    private Object store(StoreNode store) {
+        var to = (Obj)val(store.ptr());
+        var off = vall(store.off());
+        var val = val(store.val());
+        var idx = getFieldIndex(to.struct, store, (Long)off);
+        if( idx==to.struct._fields.length-1 && to.struct.isAry() ) {
+            long len = to.fields.length - to.struct._fields.length + 1;
+            long i = offToIdx(off, to.struct);
+            if( i < 0 || i >= len )
+                throw new RuntimeException("Array index out of bounds " + off + " <= " + len);
+            to.fields[(int)i+to.struct._fields.length-1] = val;
+        } else
+            to.fields[idx] = val;
+        return null;
+    }
+
+    private static boolean isTrue(Object obj) {
+        if (obj == null) return false;
+        if (obj instanceof Number n) return n.longValue() != 0;
+        return true;
+    }
+
+    private Object val(Node node) {
+        return values[node._nid];
+    }
+
+    private long vall(Node node) {
+        var v = val(node);
+        if (v instanceof Number n) return n.longValue();
+        throw new AssertionError("Not a long " + v);
+    }
+    private double vald(Node node) {
+        var v = val(node);
+        if (v instanceof Number n) return n.doubleValue();
+        if( v == null ) return 0;
+        throw new AssertionError("Not a double " + v);
+    }
+
+    private Object cons(ConstantNode cons) {
+        var type = cons.compute();
+        if (type instanceof TypeInteger i) return i.isConstant() ? i.value() : Integer.MAX_VALUE;
+        if (type instanceof TypeFloat i) return i.value();
+        return null;
+    }
+
+    private Object exec(Node node) {
+        return switch (node) {
+            case ConstantNode cons  -> cons(cons);
+            case AddNode      add   -> vall(add.in(1)) + vall(add.in(2));
+            case AddFNode     add   -> vald(add.in(1)) + vald(add.in(2));
+            case BoolNode.EQF eq    -> vald(eq.in(1)) == vald(eq.in(2)) ? 1L : 0L;
+            case BoolNode.LEF le    -> vald(le.in(1)) <= vald(le.in(2)) ? 1L : 0L;
+            case BoolNode.LTF lt    -> vald(lt.in(1)) <  vald(lt.in(2)) ? 1L : 0L;
+            case BoolNode.EQ  eq    -> Objects.equals(val(eq.in(1)), val(eq.in(2))) ? 1L : 0L;
+            case BoolNode.LE  le    -> vall(le.in(1)) <= vall(le.in(2)) ? 1L : 0L;
+            case BoolNode.LT  lt    -> vall(lt.in(1)) <  vall(lt.in(2)) ? 1L : 0L;
+            case DivNode      div   -> div(div);
+            case DivFNode     div   -> div(div);
+            case MinusNode    minus -> -vall(minus.in(1));
+            case MinusFNode   minus -> -vald(minus.in(1));
+            case MulNode      mul   -> vall(mul.in(1)) * vall(mul.in(2));
+            case MulFNode     mul   -> vald(mul.in(1)) * vald(mul.in(2));
+            case NotNode      not   -> isTrue(val(not.in(1))) ? 0L : 1L;
+            case SubNode      sub   -> vall(sub.in(1)) - vall(sub.in(2));
+            case SubFNode     sub   -> vald(sub.in(1)) - vald(sub.in(2));
+            case ShlNode      shl   -> vall(shl.in(1)) << vall(shl.in(2));
+            case ShrNode      shr   -> vall(shr.in(1)) >>> vall(shr.in(2));
+            case SarNode      sar   -> vall(sar.in(1)) >> vall(sar.in(2));
+            case AndNode      and   -> vall(and.in(1)) & vall(and.in(2));
+            case  OrNode      or    -> vall(or .in(1)) | vall(or .in(2));
+            case XorNode      xor   -> vall(xor.in(1)) ^ vall(xor.in(2));
+            case CastNode     cast  -> val(cast.in(1));
+            case ToFloatNode  cast  -> (double)vall(cast.in(1));
+            case LoadNode     load  -> load(load);
+            case StoreNode    store -> store(store);
+            case NewNode      alloc -> alloc(alloc);
+            case CProjNode    cproj -> ((Object[])val(cproj.ctrl()))[cproj._idx];
+            case ProjNode     proj  -> ((Object[])val( proj.in(0) ))[ proj._idx];
+            case MemMergeNode mem   -> null;
+            case ReadOnlyNode ro    -> val(ro.in(1));
+            case CallNode     call  -> Utils.TODO(); // should not reach here, go the IfNode route
+            default                 -> throw new AssertionError("Unexpected node " + node);
+        };
+    }
+
+    /**
+     * Run the graph until either a return is found or the number of loop iterations are done.
+     */
+    public Object evaluate(long parameter, int loops) {
+        if (start == null) return Status.TIMEOUT;
+        var s = new Object[start.compute()._types.length];
+        s[1] = MEMORY;
+        s[2] = parameter;
+        values[start._nid] = s;
+        int i=0;
+        Scheduler.Block block = this.startBlock;
+        for(;;) {
+            for(; i<block.nodes().length;i++) values[block.nodes()[i]._nid] = exec(block.nodes()[i]);
+            i=0;
+            switch (block.exit()) {
+            case null:
+                return Status.FALLTHROUGH;
+            case ReturnNode ret :  return val(ret .expr());
+            case IfNode ifn:
+                block = block.next()[isTrue(val(ifn.in(1))) ? 0 : 1];
+                if (block == null) return Status.FALLTHROUGH;
+                break;
+            case RegionNode region:
+                if (loops-- <= 0) return Status.TIMEOUT;
+                int exit = block.exitId();
+                assert exit > 0 && region.nIns() > exit;
+                block = block.next()[0];
+                assert block != null;
+                for (; i < block.nodes().length; i++) {
+                    if (!(block.nodes()[i] instanceof PhiNode phi)) break;
+                    var val = region instanceof FunNode fun && "main".equals(fun._name) && ((ParmNode)phi)._idx==2 && exit==1
+                            ? parameter
+                            : val(phi.in(exit));
+                    phiCache.add(val);
+                }
+                for (i=0; i<phiCache.size(); i++) {
+                    values[block.nodes()[i]._nid] = phiCache.get(i);
+                }
+                phiCache.clear();
+                break;
+            default:
+                throw Utils.TODO("Unexpected control node " + block.exit());
+            }
+        }
+    }
+
+    public static Object evaluate(StopNode graph) {
+        return evaluate(graph, 0);
+    }
+
+    public static Object evaluate(StopNode graph, long parameter) {
+        return evaluate(graph, parameter, 1000);
+    }
+
+    public static Object evaluate(StopNode graph, long parameter, int loops) {
+        var res = evaluateWithResult(graph, parameter, loops);
+        if (res == Status.TIMEOUT) throw new RuntimeException("Timeout");
+        return res;
+    }
+
+    public static Object evaluateWithResult(StopNode graph, long parameter, int loops) {
+        return new Evaluator(graph).evaluate(parameter, loops);
+    }
+
+}
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/evaluator/Scheduler.java b/chapter22/src/test/java/com/seaofnodes/simple/evaluator/Scheduler.java
new file mode 100644
index 00000000..7ba9272f
--- /dev/null
+++ b/chapter22/src/test/java/com/seaofnodes/simple/evaluator/Scheduler.java
@@ -0,0 +1,606 @@
+package com.seaofnodes.simple.evaluator;
+
+import com.seaofnodes.simple.Utils;
+import com.seaofnodes.simple.node.*;
+import com.seaofnodes.simple.type.Type;
+
+import java.util.*;
+
+/**
+ * A late scheduler for test cases.
+ * <br>
+ * <br>
+ * This scheduler is used for tests and is not the final scheduler.
+ * <br>
+ * <br>
+ * The scheduler schedules not as late as possible. Since it is just for test cases this is fine.
+ * A better scheduler will try to place nodes outside of loops. Due to the schedule late strategy
+ * this scheduler might place initialization code in loops.
+ * <br>
+ * We schedule late here since memory edges have some implicit information. There can only be one
+ * memory edge (for a field) at a time. However, before <code>if</code> statements this might split.
+ * When scheduling early a store might be moved out of the loop but then there are two edges alive.
+ * The one through the store node and the adjacent one. This is an invalid schedule and instead of
+ * handling this case a late scheduler does not have this problem as memory edges are combined
+ * through phi nodes.
+ * <br>
+ * <br>
+ * A bit about this scheduler. It first discovers all alive nodes and allocates side data for them.
+ * Then the control flow graph is build. Then, all phis are placed and finally all the remaining nodes
+ * in an order where a node is placed when all alive uses are placed. Finally, the output is produced.
+ */
+public class Scheduler {
+
+    /**
+     * A basic block with a schedule of the containing nodes.
+     *
+     * @param nodes The nodes in the final schedule of this block
+     * @param exit The exit node of this block.
+     * @param exitId In case the next block is a region this gives the entry id into the region.
+     * @param next The next blocks.
+     */
+    public record Block(Node[] nodes, Node exit, int exitId, Block[] next) {}
+
+    /**
+     * Definition of a block in the building process.
+     */
+    private static class BasicBlock {
+
+        /**
+         * Dominator of this block
+         */
+        final BasicBlock dom;
+        /**
+         * Id of this block where <code>a.depth < b.depth</code> means that a is before b or
+         * both are in different branches.
+         */
+        final int depth;
+        /**
+         * Previous blocks
+         */
+        final BasicBlock[] prev;
+        /**
+         * Entry to this block
+         */
+        final Node entry;
+        /**
+         * Schedules node in reverse order.
+         */
+        final ArrayList<Node> reverseSchedule = new ArrayList<>();
+
+        /**
+         * Initialize the block.
+         * @param entry The node that started this block
+         * @param depth The depth of this node. All previous nodes need to have a lower value.
+         * @param prev The previous blocks.
+         */
+        BasicBlock(Node entry, int depth, BasicBlock... prev) {
+            BasicBlock dom = null;
+            int max = -1;
+            for(var bb: prev) {
+                max = Math.max(max, bb.depth);
+                dom = dom==null?bb:dom(dom, bb);
+            }
+            assert depth > max;
+            this.dom = dom;
+            this.depth = depth;
+            this.entry = entry;
+            this.prev = prev;
+        }
+        BasicBlock(Node entry, BasicBlock prev) {
+            this(entry,prev.depth+1,prev);
+        }
+
+    }
+
+    /**
+     * Ancillary data for nodes used during the scheduling process.
+     */
+    private static class NodeData {
+
+        /**
+         * The node this ancillary data is used for.
+         */
+        final Node node;
+
+        /**
+         * Number of alive users not yet scheduled.
+         */
+        int users = 1;
+
+        /**
+         * Block into which the node should be placed so far.
+         * This will be updated with every placed use.
+         */
+        BasicBlock block;
+
+        /**
+         * Initialize ancillary data for a node
+         * @param node The node this ancillary data is associated with.
+         */
+        NodeData(Node node) {
+            this.node = node;
+        }
+
+    }
+
+    /**
+     * Ancillary data for nodes.
+     */
+    private final IdentityHashMap<Node, NodeData> data = new IdentityHashMap<>();
+    /**
+     * List of nodes which can be placed since all users are placed.
+     */
+    private final Stack<NodeData> scheduleQueue = new Stack<>();
+
+    /**
+     * Get the ancillary data for an alive node.
+     * @param node The node for which the ancillary data is requested.
+     * @return The ancillary data for the node.
+     */
+    NodeData d(Node node) {
+        return od(node).orElseThrow(AssertionError::new);
+    }
+
+    /**
+     * Get the ancillary data for a potentially dead node.
+     * @param node The node for which the ancillary data is requested.
+     * @return The ancillary data for the node an alive node or
+     * <code>Optional.empty()</code> for <code>null</code> or dead nodes.
+     */
+    Optional<NodeData> od(Node node) {
+        return Optional.ofNullable(data.get(node));
+    }
+
+    /**
+     * Checks a node for validity
+     * @param data The node to check.
+     * @return true if all placed inputs are before this node.
+     */
+    private boolean isValid(NodeData data) {
+        return data.node._inputs.stream()
+                .map(i->i==null?null:d(i))
+                .map(d->d==null||d.users>0?null:d.block)
+                .allMatch(d->d==null||dom(d, data.block)==d);
+    }
+
+    /**
+     * Checks that node is not XCtrl.
+     * @param node The node to check.
+     * @return true if the node is not XCtrl.
+     */
+    private static boolean isNotXCtrl(Node node) {
+        return !(node instanceof ConstantNode c && c.compute() == Type.XCONTROL) && !(node instanceof XCtrlNode);
+    }
+
+    /**
+     * Return the dominator of <code>a</code> and <code>b</code>
+     * @param a Block a
+     * @param b Block b
+     * @return The dominator of <code>a</code> and <code>b</code>
+     */
+    private static BasicBlock dom(BasicBlock a, BasicBlock b) {
+        while (a!=b) {
+            if (a.depth >= b.depth) a=a.dom;
+            if (b.depth > a.depth) b=b.dom;
+        }
+        return a;
+    }
+
+    /**
+     * Return if a is before b.
+     * @param a Block a
+     * @param b Block b
+     * @return true is a is before b.
+     */
+    private static boolean isBefore(BasicBlock a, BasicBlock b) {
+        while (b.depth > a.depth) {
+            while (b.dom.depth > a.depth) b = b.dom;
+            for (int i=0; i<b.prev.length-1; i++) {
+                if (isBefore(a, b.prev[i])) return true;
+            }
+            b = b.prev[b.prev.length-1];
+        }
+        return a == b;
+    }
+
+    /**
+     * Is node placed during the control flow graph build.
+     * @param data Node to check.
+     * @return true if node is placed during the control flow graph build.
+     */
+    private static boolean isPinnedNode(NodeData data) {
+        return data.node instanceof CFGNode || data.node instanceof PhiNode;
+    }
+
+    /**
+     * Refine placement of a node.
+     * @param data The node to refine.
+     * @param block The block before the node should be scheduled.
+     */
+    private void refinePlacement(NodeData data, BasicBlock block) {
+        assert !isPinnedNode(data);
+        data.block = data.block == null ? block : dom(data.block, block);
+        assert isValid(data);
+    }
+
+    /**
+     * Refine placement if before is happening before data
+     * @param data The node for which the placement should be refined.
+     * @param before The node before which the data node should be placed.
+     */
+    private void optionalRefinePlacement(NodeData data, Node before) {
+        od(before).ifPresent(d->{
+            // before might be in a different branch. So check this case with isBefore
+            // and only refine the placement if it is not in a different branch.
+            if (isBefore(d.block, data.block)) refinePlacement(data, d.block);
+        });
+    }
+
+    /**
+     * Schedule all nodes not yet scheduled.
+     */
+    private void doSchedule() {
+        while (!scheduleQueue.isEmpty()) {
+            var data = scheduleQueue.pop();
+            assert !isPinnedNode(data);
+
+            assert data.block != null;
+            assert data.users == 0;
+
+            if (data.node instanceof MemOpNode l && l._isLoad) {
+                assert isValid(data);
+                // Handle anti-deps of load nodes.
+                // At this point all anti-dep nodes are scheduled,
+                // but they did not refine the placement
+                // so do that now.
+                var mem = data.node.in(1);
+                for(var out : mem._outputs) {
+                    if (out instanceof PhiNode p) {
+                        var r = p.in(0);
+                        for (int i = 1; i < p.nIns(); i++) {
+                            if (p.in(i) == mem) optionalRefinePlacement(data, r.in(i));
+                        }
+                    } else if (!(out instanceof MemOpNode ld && ld._isLoad)) {
+                        optionalRefinePlacement(data, out);
+                    }
+                }
+            }
+
+            assert isValid(data);
+            data.block.reverseSchedule.add(data.node);
+
+            for(var in:data.node._inputs) {
+                if (in!=null) update(d(in), data.block);
+            }
+            if (data.node instanceof MemOpNode s && !s._isLoad) {
+                // Store nodes have anti-deps to load nodes.
+                // So decrease the uses of these loads when the store is placed.
+                for (var out: ((Node)s).in(1)._outputs) {
+                    if (out instanceof MemOpNode ld && ld._isLoad) od(out).ifPresent(this::decUsers);
+                }
+            }
+        }
+
+        // Now all nodes should be placed and have a block assigned
+        assert this.data.values().stream().noneMatch(d->d.block==null);
+    }
+
+    /**
+     * Decrement the not-yet-placed users of a block.
+     * @param data The node for which the users should be decremented.
+     */
+    private void decUsers(NodeData data) {
+        assert data.users > 0;
+        if (--data.users == 0) {
+            assert data.block != null;
+            assert isValid(data);
+
+            // When all users are gone this node can be scheduled.
+            scheduleQueue.push(data);
+        }
+    }
+
+    /**
+     * Update the placement of a node
+     * @param data The node to update
+     * @param block The block before which the node should happen.
+     */
+    private void update(NodeData data, BasicBlock block) {
+        assert block != null;
+        if (data.users == 0) {
+            assert isPinnedNode(data);
+            return;
+        }
+        refinePlacement(data, block);
+        decUsers(data);
+    }
+
+    /**
+     * Checks if a CFG node is ready to be placed. This is used for regions joining branches.
+     * @param node The CFG node to check
+     * @return true if all parents of a CFG node are placed.
+     */
+    private boolean isCFGNodeReady(Node node) {
+        if (node instanceof LoopNode l) {
+            assert d(l.in(1)).block != null;
+        } else if (node instanceof RegionNode r) {
+            for(int i=1; i<r.nIns(); i++) {
+                if (od(r.in(i)).map(d->d.block==null).orElse(false)) return false;
+            }
+        } else if (node instanceof XCtrlNode) {
+            return false;
+        } else {
+            assert d(node.in(0)).block != null;
+        }
+        return true;
+    }
+
+    /**
+     * Schedule all phi nodes.
+     * @param phiQueue List of all the phi nodes to schedule.
+     */
+    private void schedulePhis(Stack<NodeData> phiQueue) {
+        while(!phiQueue.empty()) {
+            var data = phiQueue.pop();
+            var phi = (PhiNode) data.node;
+            var r = phi.in(0);
+            data.block = d(r).block;
+            for(int i=1; i<phi.nIns(); i++) {
+                var in = phi.in(i);
+                od(r.in(i)).ifPresent(d->update(d(in), d.block));
+            }
+        }
+    }
+
+    /**
+     * Build the control flow graph.
+     * @param start The start node.
+     */
+    private void doBuildCTF(StartNode start) {
+        var queue = new Stack<NodeData>();
+        var phiQueue = new Stack<NodeData>();
+        queue.push(d(start));
+        while (!queue.isEmpty()) {
+            var data = queue.pop();
+            var node = data.node;
+            assert node instanceof CFGNode;
+            BasicBlock block = switch (node) {
+            case StartNode s -> new BasicBlock(s, 0);
+            case LoopNode l -> new BasicBlock(l, d(l.in(1)).block);
+            case RegionNode r -> {
+                    var prev = new ArrayList<BasicBlock>();
+                    int depth = 0;
+                    for(int i=1; i<r.nIns(); i++) {
+                        if( !od(r.in(i)).isPresent() ) continue;
+                        BasicBlock bb = d(r.in(i)).block;
+                        prev.add(bb);
+                        depth = Math.max(depth,bb.depth);
+                    }
+                    yield new BasicBlock(r, depth+1, prev.toArray(BasicBlock[]::new));
+            }
+            case IfNode i -> d(i.in(0)).block;
+            case ReturnNode ret -> d(ret .in(0)).block;
+            case CallNode call -> throw Utils.TODO();
+            default -> new BasicBlock(node, d(node.in(0)).block);
+            };
+            data.block = block;
+            if (node instanceof RegionNode r) {
+                // Regions might have phis which need to be scheduled.
+                // Put them on a list for later scheduling.
+                for (var out:r._outputs) {
+                    if (out instanceof PhiNode p) {
+                        var d = this.data.get(p);
+                        if (d!=null) {
+                            d.users=0;
+                            phiQueue.push(d);
+                        }
+                    }
+                }
+            }
+            if( node instanceof FunNode fun ) {
+                // Cannot find CFG user from fun via a naive search, because always find
+                // Return but Return is not always the one CFG user.
+                CFGNode n = fun.uctrl();
+                assert isCFGNodeReady(n) && d(n).block==null;
+                queue.push(d(n));
+            } else if( !(node instanceof ReturnNode) ) {
+                for (Node n : node._outputs)
+                    if(n instanceof CFGNode && isCFGNodeReady(n) && d(n).block == null)
+                        queue.push(d(n));
+            }
+            var b = block;
+            for(var in:data.node._inputs) od(in).ifPresent(d->update(d, b));
+        }
+
+        // Schedule all phi nodes.
+        schedulePhis(phiQueue);
+    }
+
+    /**
+     * Mark a node alive and create ancillary data for it.
+     * @param queue List into which this node should be placed if it needs to be visited.
+     * @param node Node which should be marked alive.
+     * @param cfg If this node is a CFG node.
+     */
+    private void markAlive(Stack<NodeData> queue, Node node, boolean cfg) {
+        var nd = od(node).orElse(null);
+        if (nd != null) {
+            // Node was already visited, just increase the users.
+            if (nd.users>0) nd.users++;
+            return;
+        }
+        assert node instanceof CFGNode == cfg;
+        assert isNotXCtrl(node);
+        nd = new NodeData(node);
+        if (cfg) nd.users=0;
+        data.put(node, nd);
+        queue.push(nd);
+    }
+
+    /**
+     * Mark all alive nodes.
+     * First all CFG nodes are marked, then all other nodes.
+     * @param node THe start node.
+     */
+    private void doMarkAlive(Node node) {
+        var cfgQueue = new Stack<NodeData>();
+        var dataQueue = new Stack<NodeData>();
+        var mem = new Stack<NodeData>();
+        markAlive(cfgQueue, node, true);
+        // Mark all CFG nodes.
+        while (!cfgQueue.isEmpty()) {
+            var data = cfgQueue.pop();
+            node = data.node;
+            assert node instanceof CFGNode;
+            if (!(node instanceof ReturnNode) ) {
+                for (var out : node._outputs) if (out!=null && out instanceof CFGNode && isNotXCtrl(out)) markAlive(cfgQueue, out, true);
+            }
+            for (var in : node._inputs) if(in!=null && !(in instanceof CFGNode) && isNotXCtrl(in)) markAlive(dataQueue, in, false);
+        }
+        // Mark all other nodes.
+        while (!dataQueue.isEmpty()) {
+            var data = dataQueue.pop();
+            node = data.node;
+            assert !(node instanceof CFGNode);
+            if (node instanceof PhiNode phi) {
+                var r = phi.in(0);
+                for (int i=1; i<phi.nIns(); i++) {
+                    if (od(r.in(i)).isPresent()) markAlive(dataQueue, phi.in(i), false);
+                }
+            } else {
+                for (var in : node._inputs) if (in != null && !(in instanceof CFGNode)) markAlive(dataQueue, in, false);
+            }
+            if (node instanceof MemOpNode s && !s._isLoad) mem.push(data);
+        }
+        // Handle store nodes and increase load with an anti-dep to the store.
+        while (!mem.isEmpty()) {
+            var data = mem.pop();
+            node = data.node;
+            for(var out:node.in(1)._outputs) {
+                if (out instanceof MemOpNode ld && ld._isLoad) od(out).ifPresent(d->d.users++);
+            }
+        }
+    }
+
+    /**
+     * Helper function to append the nodes of a block to an array of nodes
+     * @param arr The array the nodes of a block should be appended to.
+     * @param node A potentially separator node
+     * @param block The block from which the nodes should be appended.
+     * @return The combined new array.
+     */
+    private static Node[] appendNodes(Node[] arr, Node node, BasicBlock block) {
+        var idx = arr.length;
+        arr = Arrays.copyOf(arr, arr.length+block.reverseSchedule.size()+(node==null?0:1));
+        if (node != null) arr[idx++] = node;
+        for(int i=block.reverseSchedule.size()-1;i>=0;i--) {
+            arr[idx++] = block.reverseSchedule.get(i);
+        }
+        return arr;
+    }
+
+    /**
+     * Find the CFG output of a node
+     * @param node The node
+     * @return The CFG output of the node.
+     */
+    private static CFGNode findSingleCFGOut(Node node) {
+        if (node instanceof StartNode) {
+            for(var n:node._outputs)
+                if (n instanceof FunNode fun && "main".equals(fun._name) )
+                   return fun;
+            return null;
+        }
+        if( node instanceof FunNode fun ) return fun.uctrl();
+        assert node._outputs.stream().filter(x -> x instanceof CFGNode).limit(2).count()<=1;
+        for(var n:node._outputs) if(n instanceof CFGNode cfg) return cfg;
+        return null;
+    }
+
+    /**
+     * Build the final data structure after all the scheduling happened.
+     * @param start The start node
+     * @return The final schedule.
+     */
+    private Block build(Node start) {
+        var blocks = new IdentityHashMap<Node, Block>();
+        var queue = new Stack<NodeData>();
+        queue.push(d(start));
+
+        // Visit all CFG nodes and create blocks for them.
+        // This can combine blocks.
+        while(!queue.isEmpty()) {
+            var data = queue.pop();
+            var first = data.node;
+            Node prev;
+            var last = first;
+            Node[] arr = new Node[0];
+            if (first instanceof RegionNode) {
+                var nodes = new ArrayList<Node>();
+                for(var out: first._outputs) {
+                    if (out instanceof PhiNode) {
+                        if(od(out).isPresent()) nodes.add(out);
+                    }
+                }
+                arr = nodes.toArray(arr);
+            }
+            arr = appendNodes(arr, null, data.block);
+            assert !(first instanceof IfNode);
+            for(;;) {
+                prev = last;
+                last = findSingleCFGOut(last);
+                if (last == null) break;
+                if (last instanceof RegionNode) {
+                    if (blocks.get(last) == null && last != first)
+                        queue.push(d(last));
+                    break;
+                }
+                if (last instanceof ReturnNode) break;
+                if (last instanceof IfNode if_) {
+                    for(var out:if_._outputs) if (out instanceof CFGNode && blocks.get(out) == null) queue.push(d(out));
+                    break;
+                }
+                data = d(last);
+                arr = appendNodes(arr, data.node, data.block);
+            }
+            blocks.put(first, switch(last) {
+                case null -> new Block(arr, null, -1, new Block[0]);
+                case IfNode i -> new Block(arr, i, -1, new Block[2]);
+                case RegionNode r -> new Block(arr, r, r._inputs.find(prev), new Block[1]);
+                case ReturnNode r -> new Block(arr, r   , -1, new Block[0]);
+                default -> throw new AssertionError("Unexpected block exit node");
+            });
+        }
+        // Update the next pointer of all blocks.
+        for (var block: blocks.values()) {
+            switch(block.exit) {
+                case null: break;
+                case IfNode i:
+                    for(var out:i._outputs) if (out instanceof CProjNode p) block.next[p._idx] = blocks.get(p);
+                    break;
+                case RegionNode r:
+                    block.next[0] = blocks.get(r);
+                    break;
+                default:
+                    assert block.exit instanceof ReturnNode;
+            }
+        }
+        // And return the block for the start node.
+        return blocks.get(start);
+    }
+
+    /**
+     * Create a schedule for the program reachable from start.
+     * @param start The start node
+     * @return The final schedule.
+     */
+    public static Scheduler.Block schedule(StartNode start) {
+        var scheduler = new Scheduler();
+        scheduler.doMarkAlive(start);
+        scheduler.doBuildCTF(start);
+        scheduler.doSchedule();
+        return scheduler.build(start);
+    }
+
+}
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/fuzzer/Fuzzer.java b/chapter22/src/test/java/com/seaofnodes/simple/fuzzer/Fuzzer.java
new file mode 100644
index 00000000..30a548ad
--- /dev/null
+++ b/chapter22/src/test/java/com/seaofnodes/simple/fuzzer/Fuzzer.java
@@ -0,0 +1,174 @@
+package com.seaofnodes.simple.fuzzer;
+
+import com.seaofnodes.simple.Parser;
+import com.seaofnodes.simple.Eval2;
+import com.seaofnodes.simple.codegen.CodeGen;
+import com.seaofnodes.simple.node.Node;
+import java.util.ArrayList;
+import java.util.Objects;
+import java.util.Random;
+import java.util.function.Consumer;
+
+/**
+ * Implementation of the fuzzer.
+ * Random testcases are generated using the ScriptGenerator.
+ * This will generate a script similar to how the parser parses it but instead of parsing it will
+ * randomly choose a variation the parser would parse and generate it.
+ * These scripts are the parsed by the parser and all exceptions are caught and filtered
+ * to only show one occurrence of one problem. This includes script which generate different
+ * results when the compiled graph with and without peeps is executed.
+ * To aid debugging scripts that cause errors are then reduced by applying rules and checking
+ * that the same issue persists.
+ */
+public class Fuzzer {
+
+    private static final int EVAL_TIMEOUT = 1000;
+
+    /**
+     * List of exceptions already encountered.
+     * This is used to filter new exceptions and discard them if they are already found.
+     */
+    private final ArrayList<Throwable> exceptions = new ArrayList<>();
+
+    /**
+     * Filter and record an exception in a script.
+     * @param e The exception caused by the script
+     * @param script The script causing the exception
+     * @param reproducer Reproducer which should be used to reproduce the test case.
+     */
+    private void recordException(Throwable e, String script, Consumer<String> reproducer, long seed) {
+        for (var ex : exceptions) {
+            if (FuzzerUtils.isExceptionFromSameCause(ex, e)) return;
+        }
+        exceptions.add(e);
+        System.out.println("========== Stack ==========");
+        e.printStackTrace(System.out);
+        System.out.println("========== Seed ==========");
+        System.out.println(seed);
+        //System.out.println("========== Code ===========");
+        //System.out.println(script);
+        System.out.println("========= Reduced =========");
+        System.out.println(Reducer.reduce(script, e, reproducer));
+        System.out.println("===========================");
+        System.out.flush();
+    }
+
+    private static boolean neq(Object a, Object b) {
+        if (Objects.equals(a, b)) return false;
+        return true;
+    }
+
+    /**
+     * Check that two graphs result in the same output when supplied with a value
+     * @param e1 Evaluator for the first graph
+     * @param e2 Evaluator for the second graph
+     * @param in The input value to both graphs to test for an equal output
+     */
+    private static void checkGraphs(CodeGen code1, CodeGen code2, long in) {
+        var r1 = Eval2.eval(code1, in, EVAL_TIMEOUT);
+        var r2 = Eval2.eval(code2, in, EVAL_TIMEOUT);
+        if( r1 == null || r2 == null ) return; // Timeout test invalid
+        if( neq(r1, r2) )
+            throw new RuntimeException("Different calculations values " + r1 + " vs " + r2);
+    }
+
+    /**
+     * Run checks for script. Compile the script with peeps enabled and disabled.
+     * Check that exceptions raised in the parser by both methods are the same and only happens if the script may be invalid.
+     * If the script was successfully parsed check that both version behave the same.
+     * @param script The script to test
+     * @param valid If the script is definitely valid. If not some exceptions may be suppressed.
+     */
+    private static void runCheck(String script, boolean valid) {
+        CodeGen code1;
+        try {
+            code1 = FuzzerUtils.parse(script, 123);
+        } catch (RuntimeException e1) {
+            try {
+                FuzzerUtils.parse(script, 456);
+            } catch (RuntimeException e2) {
+                if (FuzzerUtils.isExceptionFromSameCause(e1, e2)) {
+                    if (!valid || e1.getClass() == Parser.ParseException.class) return;
+                } else {
+                    e1.addSuppressed(e2);
+                }
+            }
+            throw e1;
+        }
+        CodeGen code2 = FuzzerUtils.parse(script, 456);
+        checkGraphs(code1, code2, 0);
+        checkGraphs(code1, code2, 1);
+        checkGraphs(code1, code2, 10);
+    }
+
+    /**
+     * Check that the script does not result in exceptions.
+     * @param script The script to test.
+     * @param valid If the script is valid or if it might contain syntax errors.
+     */
+    private void check(String script, boolean valid, long seed) {
+        try {
+            runCheck(script, valid);
+        } catch (Throwable e) {
+            recordException(e, script, s->runCheck(s, valid), seed);
+        }
+    }
+
+    /**
+     * Run one test with the given seed, and check for peephole counts.
+     * @param seed The seed to use for generating this test case
+     */
+    public int fuzzPeepTiming(long seed, int max_nids) {
+        var rand = new Random(seed);
+        var sb = new StringBuilder();
+        new ScriptGenerator(rand, sb, true).genProgram();
+        try {
+            var code = new CodeGen(sb.toString());
+
+            code.parse();
+            int nids = code.UID();
+            if( nids <= max_nids ) return max_nids; // Smaller, looking for trends as we grow
+            int parse_peeps= code._iter_cnt;
+            int parse_nops = code._iter_nop_cnt;
+            double parse_nop_ratio = (double)parse_nops/parse_peeps;
+            double parse_peeps_per_node = (double)parse_peeps/nids;
+
+            code.opto();
+            int iter_peeps= code._iter_cnt;
+            int iter_nops = code._iter_nop_cnt;
+            double iter_nop_ratio = (double)iter_nops/iter_peeps;
+            double iter_peeps_per_node = (double)iter_peeps/nids;
+
+            System.out.printf("%6d | Parsing: peeps: %5d, nops: %5d, ratio: %5.3f, last UID: %5d ps/node: %5.3f  | Iter: peeps: %6d, nops: %6d, ratio: %5.3f, ps/node: %5.3f\n",
+                              seed,
+                              parse_peeps,parse_nops,parse_nop_ratio,nids,parse_peeps_per_node,
+                              iter_peeps , iter_nops, iter_nop_ratio,      iter_peeps_per_node);
+            return nids;
+        } catch (Throwable e) {
+            // ignore exceptions, let the normal fullPeeps catch and reduce,
+            // we're interested in valid program optimizations
+        }
+        return max_nids;
+    }
+
+
+    /**
+     * Run one test with the given seed.
+     * @param seed The seed to use for generating this test case
+     */
+    public void fuzzPeeps(long seed) {
+        var rand = new Random(seed);
+        var sb = new StringBuilder();
+        var valid = new ScriptGenerator(rand, sb, true).genProgram();
+        check(sb.toString(), valid, seed);
+    }
+
+
+    /**
+     * Check that no exceptions happened.
+     * @return true if no exception happened
+     */
+    public boolean noExceptions() {
+        return exceptions.isEmpty();
+    }
+}
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/fuzzer/FuzzerUtils.java b/chapter22/src/test/java/com/seaofnodes/simple/fuzzer/FuzzerUtils.java
new file mode 100644
index 00000000..b90b663d
--- /dev/null
+++ b/chapter22/src/test/java/com/seaofnodes/simple/fuzzer/FuzzerUtils.java
@@ -0,0 +1,111 @@
+package com.seaofnodes.simple.fuzzer;
+
+import com.seaofnodes.simple.IterPeeps;
+import com.seaofnodes.simple.codegen.CodeGen;
+import com.seaofnodes.simple.node.Node;
+import com.seaofnodes.simple.node.StopNode;
+import com.seaofnodes.simple.type.TypeInteger;
+import java.io.OutputStream;
+import java.io.PrintStream;
+import java.lang.invoke.MethodHandle;
+import java.lang.invoke.MethodHandles;
+import java.lang.reflect.Field;
+import java.util.BitSet;
+
+/**
+ * Some utilities for the fuzzer.
+ */
+class FuzzerUtils {
+
+    /**
+     * Get the val of a private field
+     */
+    @SuppressWarnings("unchecked")
+    public static <T> T getFieldValue(Object obj, String name) throws NoSuchFieldException, IllegalAccessException {
+        return (T) (obj instanceof Class<?> clz ? getField(clz, name).get(null) : getField(obj.getClass(), name).get(obj));
+    }
+
+    /**
+     * Get access to a private field
+     */
+    public static Field getField(Class<?> clz, String name) throws NoSuchFieldException {
+        var field = clz.getDeclaredField(name);
+        try {
+            field.setAccessible(true);
+        } catch (Throwable e) {
+            // Intentionally left empty
+        }
+        return field;
+    }
+
+    /**
+     * Try to rethrow an exception or create a runtime exception and throw it.
+     */
+    public static RuntimeException rethrow(Throwable e) {
+        if (e instanceof RuntimeException re) return re;
+        if (e instanceof Error er) throw er;
+        return new RuntimeException(e);
+    }
+
+    /**
+     * Some problems might trigger debug output. Suppress this output with a null print stream during fuzzing.
+     */
+    public static final PrintStream NULL_PRINT_STREAM = new PrintStream(OutputStream.nullOutputStream());
+
+    /**
+     * Check that the messages are similar.
+     */
+    private static boolean similarMessages(String a, String b) {
+        if (a == null || b == null) return true;
+        a = a.replaceAll("'\\w+'", "'normalized'").replaceAll("variable \\w+", "variable normalized");
+        b = b.replaceAll("'\\w+'", "'normalized'").replaceAll("variable \\w+", "variable normalized");
+        return a.equals(b);
+    }
+
+    /**
+     * Check if both stack traces have the same first entry. Empty stack traces can happen with NPE optimization
+     * and allow the other to be any stack trace.
+     */
+    private static boolean sameStackTraceOrigin(StackTraceElement[] a, StackTraceElement[] b) {
+        if (a == null || a.length == 0 || b == null || b.length == 0) return true; // One or both stack traces are missing.
+        return a[0].equals(b[0]);
+    }
+
+    /**
+     * Checks if two exceptions are caused by the same problem.
+     */
+    public static boolean isExceptionFromSameCause(Throwable a, Throwable b) {
+        if (a == null || b == null) return a == b; // Handle the null case
+        if (a.getClass() != b.getClass()) return false; // Different classes
+        if (!similarMessages(a.getMessage(), b.getMessage())) return false; // Different messages. Null is allowed as wildcard
+        var s1 = a.getStackTrace();
+        var s2 = b.getStackTrace();
+        if (!sameStackTraceOrigin(s1, s2)) return false; // Different stack trace origins
+        if (!isExceptionFromSameCause(a.getCause(), b.getCause())) return false; // Different causes
+        var o1 = a.getSuppressed();
+        var o2 = b.getSuppressed();
+        if (o1 == null || o2 == null || o1.length != o2.length) return o1 == o2; // Different suppression
+        for (int i=0; i<o1.length; i++) {
+            if (!isExceptionFromSameCause(o1[i], o2[i])) return false; // Different suppression
+        }
+        return true;
+    }
+
+    /**
+     * Parse script with peepholes enabled or disabled
+     */
+    public static CodeGen parse(String script, long workListSeed) {
+        var err = System.err;
+        var out = System.out;
+        try {
+            System.setErr(NULL_PRINT_STREAM);
+            System.setOut(NULL_PRINT_STREAM);
+            var code = new CodeGen(script, TypeInteger.BOT, workListSeed);
+            return code.driver(CodeGen.Phase.LocalSched);
+        } finally {
+            System.setErr(err);
+            System.setOut(out);
+        }
+    }
+
+}
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/fuzzer/Reducer.java b/chapter22/src/test/java/com/seaofnodes/simple/fuzzer/Reducer.java
new file mode 100644
index 00000000..3731b40c
--- /dev/null
+++ b/chapter22/src/test/java/com/seaofnodes/simple/fuzzer/Reducer.java
@@ -0,0 +1,176 @@
+package com.seaofnodes.simple.fuzzer;
+
+import java.util.Arrays;
+import java.util.function.BiConsumer;
+import java.util.function.Consumer;
+import java.util.function.Predicate;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+/**
+ * This class is used to reduce test cases created by the fuzzer.
+ * It applies rewrite rules to the test case and checks that the
+ * test still produces the same exception.
+ * This is done in a fixpoint iteration until every rewrite produces
+ * no or a different exception.
+ */
+public class Reducer {
+
+    private interface Replacer extends BiConsumer<StringBuilder, Matcher> {}
+
+    /**
+     * Holder for the rewrite rules
+     */
+    private record Replace(Pattern pattern, boolean iterate, Replacer... replacements) {
+        Replace(Pattern p, Object... replacements) {
+            this(p, replacements[0] == Boolean.TRUE, Arrays.stream(replacements).filter(o->!(o instanceof Boolean)).map(Replace::from).toArray(Replacer[]::new));
+        }
+        private static Replacer from(Object o) {
+            if (o instanceof Replacer r) return r;
+            if (o instanceof Integer i) return (s, m)->s.append(m.group(i));
+            if (o instanceof String r) return (s, m)->s.append(r);
+            throw new IllegalArgumentException();
+        }
+    }
+
+    /**
+     * List of rewrite rules.
+     */
+    private static final Replace[] REPLACEMENTS = {
+            new Replace(Pattern.compile("\\b(?:[^\\W0]|\\w\\w+)\\b"), "0", "1"),
+            new Replace(Pattern.compile("(?<=\\n|^)[^\\n]+(?=\\n|$)"), true, ""),
+            new Replace(Pattern.compile("(?<=[+\\-*/<>=(])--"), ""),
+            new Replace(Pattern.compile("\\b--"), "+"),
+            new Replace(Pattern.compile("-"), ""),
+            new Replace(Pattern.compile("\\b\\+-"), "-"),
+            new Replace(Pattern.compile("(?<![+\\-*/<>=])(?:-|\\*|/|>=|<=|>|<|!=|==)(?![+\\-*/<>=])"), "+"),
+            new Replace(Pattern.compile("\\{((?:[^{}]|\\{})+)(?:\\n[ \\t]*)?}"), "", "{}", 1),
+            new Replace(Pattern.compile("(?<=\\n|^)([ \\t]*)\\{\\n(.*?)\\n\\1}", Pattern.DOTALL), 2),
+            new Replace(Pattern.compile("\\(([^()]+)\\)"), 1),
+            new Replace(Pattern.compile("\\d+\\+"), ""),
+            new Replace(Pattern.compile("\\+\\d+"), ""),
+            new Replace(Pattern.compile("\\n\\n+"), "\n"),
+            new Replace(Pattern.compile("^\\n+|\\n+$"), ""),
+            new Replace(Pattern.compile("else *"), ""),
+            new Replace(Pattern.compile("\\bif\\([^()]+\\) *"), ""),
+            new Replace(Pattern.compile("\\bwhile\\([^()]+\\) *"), ""),
+            new Replace(Pattern.compile("\\bstruct \\w+ \\{[^{}]*}"), "")
+    };
+
+    /**
+     * Predicate to test if the reduced script generates the same error.
+     */
+    private final Predicate<String> tester;
+
+    /**
+     * Create a reducer with a test function.
+     * @param tester Test function which returns true when the same issue is found in the script.
+     */
+    private Reducer(Predicate<String> tester) {
+        this.tester = tester;
+    }
+
+    /**
+     * Rewrites the script with one rewrite rule.
+     */
+    private String doReplacement(String script, Pattern pattern, Replacer[] replacements) {
+        var matcher = pattern.matcher(script);
+        var sb = new StringBuilder();
+        var last = 0;
+        var skip = 0;
+        outer:
+        while (matcher.find(last + skip)) {
+            sb.append(script, last, matcher.start());
+            last = matcher.end();
+            skip = last == matcher.start() ? 1 : 0;
+            var pos = sb.length();
+            for (var replacement : replacements) {
+                replacement.accept(sb, matcher);
+                var tail = sb.length();
+                sb.append(script, last, script.length());
+                if (tester.test(sb.toString())) {
+                    sb.setLength(tail);
+                    continue outer;
+                }
+                sb.setLength(pos);
+            }
+            last = matcher.start();
+            skip = 1;
+        }
+        sb.append(script, last, script.length());
+        return sb.toString();
+    }
+
+    /**
+     * Clean up variable names from the random ones generated by the fuzzer.
+     */
+    private String cleanVariables(String script) {
+        var matcher = Pattern.compile("\\b([0-9a-zA-Z_]+) ([0-9a-zA-Z_]+)").matcher(script);
+        int[] num = {0, 0};
+        while (matcher.find()) {
+            var type = matcher.group(1);
+            var var = matcher.group(2);
+            if (type.equals("new")) continue;
+            String prefix = "v";
+            int t = 0;
+            if (type.equals("struct")) {
+                t = 1;
+                prefix = "s";
+            }
+            if (var.matches(prefix+"\\d+")) continue;
+            while (script.contains(prefix+num[t])) num[t]++;
+            var n = script.replaceAll("\\b"+var+"\\b", prefix + num[t]);
+            if (tester.test(n)) {
+                script = n;
+            }
+        }
+        return script;
+    }
+
+    /**
+     * Run all rewrite rules once.
+     */
+    private String doAllReplacements(String script) {
+        for (var replace: REPLACEMENTS) {
+            String old;
+            do {
+                old = script;
+                script = doReplacement(script, replace.pattern, replace.replacements);
+            } while (replace.iterate && !old.equals(script));
+        }
+        return script;
+    }
+
+    /**
+     * Reduce the script to a minimal version which produces the same problem with a test function.
+     * @param tester Test function which returns true when the same issue is found in the script.
+     */
+    public static String reduce(String script, Predicate<String> tester) {
+        var reducer = new Reducer(tester);
+        String old;
+        do {
+            old = script;
+            script = reducer.doAllReplacements(script);
+            script = reducer.cleanVariables(script);
+        } while (!script.equals(old));
+        return script;
+    }
+
+    /**
+     * Reduce the script to a minimal version which produces the same problem with a reproducer.
+     * @param ex The exception originally caused by the script
+     * @param reproducer Test function which throws an exception which will be checked against ex.
+     */
+    public static String reduce(String script, Throwable ex, Consumer<String> reproducer) {
+        return reduce(script, s->{
+            Throwable nex = null;
+            try {
+                reproducer.accept(s);
+            } catch (Throwable e) {
+                nex = e;
+            }
+            return FuzzerUtils.isExceptionFromSameCause(nex, ex);
+        });
+    }
+
+}
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/fuzzer/ScriptGenerator.java b/chapter22/src/test/java/com/seaofnodes/simple/fuzzer/ScriptGenerator.java
new file mode 100644
index 00000000..f119fa1a
--- /dev/null
+++ b/chapter22/src/test/java/com/seaofnodes/simple/fuzzer/ScriptGenerator.java
@@ -0,0 +1,869 @@
+package com.seaofnodes.simple.fuzzer;
+
+import com.seaofnodes.simple.Parser;
+import com.seaofnodes.simple.node.ScopeNode;
+import com.seaofnodes.simple.type.TypeInteger;
+import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Random;
+import java.util.function.Predicate;
+import static com.seaofnodes.simple.Parser.KEYWORDS;
+
+
+/**
+ * Generate a pseudo random script.
+ * This generator will generate the same script for two random number generators initialized with the same seed.
+ * To generate valid code it implements the parser but instead of parsing it emits the statements and expressions.
+ * It is guaranteed to terminate.
+ */
+public class ScriptGenerator {
+
+    private static final int MAX_STATEMENTS_PER_BLOCK = 5;
+    private static final int MAX_BINARY_EXPRESSIONS_PER_EXPRESSION = 10;
+    private static final int MAX_UNARY_EXPRESSIONS_PER_EXPRESSION = 6;
+    private static final int MAX_NAME_LENGTH = 10;
+    private static final int MAX_BLOCK_DEPTH = 4;
+    private static final int MAX_EXPRESSION_DEPTH = 10;
+    private static final int MAX_SUFFIX_RECURSIVE_DEPTH = 10;
+
+    /**
+     * Number of spaces per indentation
+     */
+    private static final int INDENTATION = 4;
+    /**
+     * Valid characters for identifiers. The last 10 are not valid for the first character.
+     */
+    private static final String VAR_CHARS = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ_0123456789";
+
+    /**
+     * Flag for a statement that it does not pass on control flow to the next statement.
+     */
+    private static final int FLAG_STOP = 0x01;
+    /**
+     * Flag for a statement that it contains a final if statement without an else branch.
+     */
+    private static final int FLAG_IF_WITHOUT_ELSE = 0x02;
+    /**
+     * Binary operators.
+     */
+    private static final String[] BINARY_OP = {"==", "!=", "<", "<=", ">", ">=", "+", "-", "*", "/", "&", ">>", ">>>", "<<"};
+    /**
+     * Unary operators.
+     */
+    private static final String[] UNARY_OP = {"-"};
+
+    private static class Type {
+        final String name;
+        Type(String name) {this.name=name;}
+        boolean isa(Type other) { return this == other; }
+    }
+
+    private static class TypeStruct extends Type {
+        record Field (String name, Type type, TypeStruct struct) {}
+        Field[] fields;
+        final TypeNullable nullable = new TypeNullable(this);
+        TypeStruct(String name) {
+            super(name);
+        }
+        boolean isa(Type other) { return this == other || other == nullable; }
+    }
+
+    private static class TypeNullable extends Type {
+
+        final Type base;
+
+        TypeNullable(Type base) {
+            super(base.name+"?");
+            this.base = base;
+        }
+
+    }
+
+    private static final Type TYPE_FLT = new Type("flt");
+
+    private static class TypeInt extends Type {
+
+        TypeInt(String name) {
+            super(name);
+        }
+
+        @Override
+        boolean isa(Type other) {
+            return super.isa(other) || other == TYPE_FLT || other instanceof TypeInt;
+        }
+    }
+
+    private static final List<TypeInt> INTTYPES = new ArrayList<>();
+
+    static {
+        for( var e : Parser.defaultTypes().entrySet() ) {
+            if( e.getValue() instanceof TypeInteger ) {
+                INTTYPES.add(new TypeInt(e.getKey()));
+            }
+        }
+    }
+
+    private static final Type TYPE_INT = INTTYPES.stream().filter(t->t.name.equals("int")).findAny().get();
+    private static final Type TYPE_BOOL = INTTYPES.stream().filter(t->t.name.equals("bool")).findAny().get();
+
+    private static class Variable {
+        final String name;
+        final Type declared;
+        final Variable shadowing;
+        Type type;
+        boolean shadowed = false;
+
+        Variable(String name, Type type, Variable var) {
+            this.name = name;
+            this.declared = type;
+            this.type = type;
+            this.shadowing = var;
+        }
+    }
+
+    /**
+     * The random number generator used for random decisions.
+     */
+    private final Random random;
+    /**
+     * Indentation depth.
+     */
+    private int indentation = 0;
+    /**
+     * Output string builder
+     */
+    private final StringBuilder sb;
+    /**
+     * Number of nested loops
+     */
+    private int loopDepth = 0;
+    /**
+     * Current scope start in the variables list.
+     */
+    private int currScopeStart = 0;
+    /**
+     * The depth of blocks allowed.
+     */
+    private int depth = MAX_BLOCK_DEPTH;
+    /**
+     * The depth of expressions allowed.
+     */
+    private int exprDepth = MAX_EXPRESSION_DEPTH;
+    /**
+     * Current variables in scope.
+     */
+    private final ArrayList<Variable> variables = new ArrayList<>();
+    /**
+     * All defined structs.
+     */
+    private final ArrayList<TypeStruct> structs = new ArrayList<>();
+    /**
+     * All forward declared structs
+     */
+    private final ArrayList<TypeStruct> forwardStructs = new ArrayList<>();
+    /**
+     * Allow to declare structs.
+     */
+    private boolean allowStructs = true;
+    /**
+     * If this needs to generate valid scripts or is also allowed to generate invalid ones.
+     */
+    private boolean generateValid;
+    /**
+     * If this script might be invalid.
+     */
+    private boolean maybeInvalid = false;
+
+
+    /**
+     *
+     * @param random the random number generator.
+     * @param sb the script will be written to this string builder.
+     * @param generateValid if the script should be guaranteed valid or if it is allowed to contain bugs.
+     */
+    public ScriptGenerator(Random random, StringBuilder sb, boolean generateValid) {
+        this.random = random;
+        this.sb = sb;
+        this.generateValid = generateValid;
+    }
+
+    /**
+     * Random number with log distribution
+     * @param max The maximum value
+     * @return A random number in the range [0, max) with higher numbers being more uncommon.
+     */
+    private int randLog(int max) {
+        max--;
+        int n = 1<<max;
+        var num = random.nextInt(n);
+        for (int i=max-1; i>=0; i--) {
+            if ((num & (1<<i))!=0) return max-i-1;
+        }
+        return max;
+    }
+
+    /**
+     * Helper function to print indentation.
+     * @return sb for chaining
+     */
+    private StringBuilder printIndentation() {
+        return sb.repeat(' ', indentation);
+    }
+
+    /**
+     * Generate a random name for variables. This might be invalid when it is a keyword.
+     * @return The random name generated
+     */
+    private StringBuilder getRandomName() {
+        int len = random.nextInt(MAX_NAME_LENGTH) + 1;
+        StringBuilder sb = new StringBuilder(len);
+        sb.append(VAR_CHARS.charAt(random.nextInt(VAR_CHARS.length()-10)));
+        for (int i=1; i<len; i++)
+            sb.append(VAR_CHARS.charAt(random.nextInt(VAR_CHARS.length())));
+        return sb;
+    }
+
+    /**
+     * Should invalid code be generated?
+     * @return True if invalid code should be generated
+     */
+    private boolean generateInvalid() {
+        if (generateValid || random.nextInt(1000)>2) return false;
+        maybeInvalid = true;
+        return true;
+    }
+
+    /**
+     * Lookup a variable by name
+     * @param name name of the variable
+     * @return The index of the variable in variables or -1
+     */
+    private int lookup(String name) {
+        for (int i=variables.size()-1; i>=0; i--) {
+            if (variables.get(i).name.equals(name)) return i;
+        }
+        return -1;
+    }
+
+    /**
+     * Lookup a variable by name
+     * @param name name of the variable
+     * @return THe variable of null if not found
+     */
+    private Variable lookupVar(String name) {
+        int idx = lookup(name);
+        return idx == -1 ? null : variables.get(idx);
+    }
+
+    /**
+     * Add a variable to the current scope
+     * @param name The name of the variable
+     * @param type The declared type of the variable
+     */
+    private void addVariable(String name, Type type) {
+        var old = lookupVar(name);
+        variables.add(new Variable(name, type, old));
+        if (old != null) old.shadowed = true;
+    }
+
+    /**
+     * Pop variables to level to
+     * @param to Level until which variables should be popped
+     */
+    private void popVariables(int to) {
+        while (variables.size() > to) {
+            var v = variables.removeLast();
+            if (v.shadowing != null) v.shadowing.shadowed = false;
+        }
+    }
+
+    /**
+     * Get a random visible variable patching pred
+     * @param pred The predicate the variable needs to match
+     * @return A random visible variable matching pred or null if no variable mached pred.
+     */
+    private Variable findVisibleVariablesMatching(Predicate<Variable> pred) {
+        int num=0;
+        for (var v:variables) {
+            if (!v.shadowed && pred.test(v)) num++;
+        }
+        if (num == 0) return null;
+        num = random.nextInt(num);
+        for (var v:variables) {
+            if (!v.shadowed && pred.test(v) && num-- == 0) return v;
+        }
+        throw new AssertionError();
+    }
+
+    /**
+     * Get a structure by name
+     * @param name Name of the structure
+     * @return The structure of null
+     */
+    private TypeStruct getStruct(String name) {
+        for (var s:structs) {
+            if (s.name.equals(name)) return s;
+        }
+        for (var s:forwardStructs) if (s.name.equals(name)) return s;
+        return null;
+    }
+
+    /**
+     * Generate a variable name. This might be new random name or a name from an outer scope.
+     * If the program is allowed to be invalid this can return keywords and already used variable names in the current scope.
+     * @return The variable name.
+     */
+    private String getVarName() {
+        if (currScopeStart > 0 && random.nextInt(10) > 7) {
+            // Use a variable outside the current scope.
+            var v = variables.get(random.nextInt(currScopeStart));
+            if (lookup(v.name) < currScopeStart) return v.name;
+            if (!generateValid) {
+                maybeInvalid = true;
+                return v.name;
+            }
+        }
+        // Generate a new random variable name
+        StringBuilder sb = getRandomName();
+        var v = sb.toString();
+        if (!generateValid && (KEYWORDS.contains(v) || lookup(v) >= currScopeStart)) {
+            maybeInvalid = true;
+            return v;
+        }
+        while (KEYWORDS.contains(v) || lookup(v) >= currScopeStart) {
+            sb.append(VAR_CHARS.charAt(random.nextInt(VAR_CHARS.length())));
+            v = sb.toString();
+        }
+        return v;
+    }
+
+    private <T> T randFromList(List<T> list) {
+        return list.get(random.nextInt(list.size()));
+    }
+
+    /**
+     * Get a random structure name
+     * @return A random structure name
+     */
+    private String getStructName() {
+        if (!structs.isEmpty() && generateInvalid()) return randFromList(structs).name;
+        if (!forwardStructs.isEmpty() && generateInvalid()) return randFromList(forwardStructs).name;
+
+        // Generate a new random struct name
+        StringBuilder sb = getRandomName();
+        var v = sb.toString();
+        if (!generateValid && (KEYWORDS.contains(v) || getStruct(v) != null)) {
+            maybeInvalid = true;
+            return v;
+        }
+        while (KEYWORDS.contains(v) || getStruct(v) != null) {
+            sb.append(VAR_CHARS.charAt(random.nextInt(VAR_CHARS.length())));
+            v = sb.toString();
+        }
+        return v;
+    }
+
+    public TypeInt getIntType() {
+        return randFromList(INTTYPES);
+    }
+
+    /**
+     * Get a random type
+     * @return A random type
+     */
+    private Type getType(boolean allowForward) {
+        int t = random.nextInt(10);
+        if( t<5 || structs.isEmpty() ) return getIntType();
+        if( t<7 ) return TYPE_FLT;
+        if (allowForward && random.nextInt(10)==0) {
+            int i=random.nextInt(forwardStructs.size()+1);
+            if (i>0) return forwardStructs.get(i-1).nullable;
+            var name = getStructName();
+            var struct = new TypeStruct(name);
+            forwardStructs.add(struct);
+            return struct.nullable;
+        }
+        TypeStruct struct = randFromList(structs);
+        if (random.nextBoolean()) return struct.nullable;
+        return struct;
+    }
+
+    private Type getType() {
+        return getType(false);
+    }
+
+    /**
+     * Generates a program and writes it into the string builder supplied in the constructor.
+     * @return If the program is allowed to be invalid returns if something potentially invalid was generated.
+     */
+    public boolean genProgram() {
+        var oldGenerateValid = generateValid;
+        if (!generateValid && random.nextBoolean()) generateValid = true;
+        this.maybeInvalid = false;
+        addVariable(ScopeNode.ARG0, TYPE_INT);
+        currScopeStart = variables.size();
+        if ((genStatements() & FLAG_STOP) == 0) {
+            if (generateValid || random.nextInt(10)<7) {
+                genReturn();
+            } else {
+                this.maybeInvalid = true;
+            }
+        }
+        generateValid = oldGenerateValid;
+        return !this.maybeInvalid;
+    }
+
+    /**
+     * Generate a list of statements.
+     * @return flags FLAG_STOP and FLAG_IF_WITHOUT_ELSE for the last statement generated
+     */
+    public int genStatements() {
+        var num = random.nextInt(MAX_STATEMENTS_PER_BLOCK * (depth+1));
+        for (int i=0; i<num; i++) {
+            printIndentation();
+            var stop = genStatement();
+            sb.append("\n");
+            if ((stop & FLAG_STOP) != 0) return stop;
+        }
+        return 0;
+    }
+
+    /**
+     * Generate a single statement
+     * @return flags FLAG_STOP and FLAG_IF_WITHOUT_ELSE for the generated statement
+     */
+    public int genStatement() {
+        return switch (random.nextInt(12)) {
+            case 0 -> allowStructs || generateInvalid() ? genStruct() : genAssignment();
+            case 1 -> genBlock();
+            case 2 -> genIf();
+            case 3 -> genCountedLoop();
+            case 4 -> genWhile();
+            case 5, 6 -> genDecl();
+            case 7, 8, 9 -> genAssignment();
+            case 10 -> genNullCheck();
+            default -> genExit();
+        };
+    }
+
+    /**
+     * Generate a new structure
+     * @return 0
+     */
+    public int genStruct() {
+        int idx = random.nextInt(forwardStructs.size()+10);
+        TypeStruct struct;
+        if (idx < 10) {
+        var name = getStructName();
+            struct = new TypeStruct(name);
+            forwardStructs.add(struct);
+        } else {
+            struct = forwardStructs.get(idx-10);
+        }
+        var fields = new TypeStruct.Field[generateInvalid() ? 0 : random.nextInt(10)];
+        sb.append("struct ").append(struct.name).append(" {\n");
+        indentation += INDENTATION;
+        for (int i=0; i<fields.length; i++) {
+            var fieldName = getRandomName();
+            var type = getType(true);
+            printIndentation().append(type.name).append(" ").append(fieldName).append(";\n");
+            fields[i] = new TypeStruct.Field(fieldName.toString(), type, struct);
+        }
+        indentation -= INDENTATION;
+        printIndentation().append("};");
+        struct.fields = fields;
+        forwardStructs.remove(struct);
+        structs.add(struct);
+        return 0;
+    }
+
+    /**
+     * Generate a statement for if, else and while blocks.
+     * This is special since it disallows declarations and prefers to generate blocks.
+     * @return flags FLAG_STOP and FLAG_IF_WITHOUT_ELSE for the generated statement
+     */
+    public int genStatementBlock() {
+        var oldAllowStructs = allowStructs;
+        allowStructs = false;
+        indentation += INDENTATION;
+        int res;
+        if (depth == 0) {
+            res = random.nextBoolean() ? genAssignment() : genExit();
+        } else {
+            depth--;
+            res = switch (random.nextInt(12)) {
+                case 1, 2, 3, 4, 5 -> {
+                    depth++;
+                    indentation -= INDENTATION;
+                    var ret = genBlock();
+                    indentation += INDENTATION;
+                    depth--;
+                    yield ret;
+                }
+                case 6 -> genIf();
+                case 7 -> genCountedLoop();
+                case 8 -> genWhile();
+                case 9 -> genAssignment();
+                case 10 -> genNullCheck();
+                default -> genExit();
+            };
+            depth++;
+        }
+        indentation -= INDENTATION;
+        allowStructs = oldAllowStructs;
+        return res;
+    }
+
+    /**
+     * Generate an exit. This can be return or break and continue when in a loop.
+     * @return FLAG_STOP
+     */
+    public int genExit() {
+        if (loopDepth == 0 && generateValid) return genReturn();
+        return switch (random.nextInt(7)) {
+            case 0,1,2 -> {
+                if (loopDepth == 0) maybeInvalid = true;
+                sb.append("continue;");
+                yield FLAG_STOP;
+            }
+            case 3,4,5 -> {
+                if (loopDepth == 0) maybeInvalid = true;
+                sb.append("break;");
+                yield FLAG_STOP;
+            }
+            default -> genReturn();
+        };
+    }
+
+    /**
+     * Generate a block statement. After a certain depth only empty blocks are generated to ensure termination of the generator.
+     * @return flag FLAG_STOP for the generated statement
+     */
+    public int genBlock() {
+        if (depth == 0) {
+            sb.append("{}");
+            return 0;
+        }
+        var oldAllowStructs = allowStructs;
+        var oldCSS = currScopeStart;
+        allowStructs = false;
+        currScopeStart = variables.size();
+        depth--;
+        sb.append("{\n");
+        indentation += INDENTATION;
+        var stop = genStatements();
+        indentation -= INDENTATION;
+        printIndentation().append("}");
+        popVariables(currScopeStart);
+        depth++;
+        currScopeStart = oldCSS;
+        allowStructs = oldAllowStructs;
+        return stop & ~FLAG_IF_WITHOUT_ELSE;
+    }
+
+    /**
+     * Generate an if statement with an optional else block.
+     * @return flags FLAG_STOP and FLAG_IF_WITHOUT_ELSE for the generated statement
+     */
+    public int genIf() {
+        sb.append("if(");
+        genExpression(TYPE_BOOL, true);
+        sb.append(") ");
+        var stop = genStatementBlock();
+        if ((stop & FLAG_IF_WITHOUT_ELSE) == 0 && random.nextInt(10) > 3) {
+            sb.append("\n");
+            printIndentation().append("else ");
+            stop &= genStatementBlock();
+        } else {
+            stop = FLAG_IF_WITHOUT_ELSE;
+        }
+        return stop;
+    }
+
+    /**
+     * Generate a block with a null check
+     * if (nullable) { handle_nullable_as_non_nullable; }
+     */
+    public int genNullCheck() {
+        var v = findVisibleVariablesMatching(va->va.declared instanceof TypeNullable);
+        if (v == null) return genIf();
+        var n = (TypeNullable)v.declared;
+        boolean negate = random.nextBoolean();
+        sb.append("if(");
+        if (negate) sb.append("!");
+        sb.append(v.name).append(")");
+        if (!negate) v.type = n.base;
+        var stop = genStatementBlock();
+        v.type = n;
+        if ((stop & FLAG_IF_WITHOUT_ELSE) == 0 && random.nextInt(10) > 3) {
+            sb.append("\n");
+            printIndentation().append("else ");
+            if (negate) v.type = n.base;
+            stop &= genStatementBlock();
+            v.type = n;
+        } else {
+            stop = FLAG_IF_WITHOUT_ELSE;
+        }
+        return stop;
+    }
+
+    /**
+     * Generate a while loop.
+     * @return 0
+     */
+    public int genWhile() {
+        sb.append("while(");
+        genExpression(TYPE_BOOL, true);
+        sb.append(") ");
+        loopDepth++;
+        genStatementBlock();
+        loopDepth--;
+        return 0;
+    }
+
+    /**
+     * Generate a counted loop of the form
+     * <code>
+     *     {
+     *         int varname = start_expr;
+     *         while (varname < end_expr) loop_body;
+     *     }
+     * </code>
+     * @return 0
+     */
+    public int genCountedLoop() {
+        if (depth == 0) return genWhile();
+        var oldCSS = currScopeStart;
+        currScopeStart = variables.size();
+        sb.append("{\n");
+        indentation += INDENTATION;
+        String name = getVarName();
+        printIndentation().append("int ").append(name).append("=");
+        genExpression(TYPE_INT, true);
+        sb.append(";\n");
+        addVariable(name, TYPE_INT);
+        printIndentation().append("while(").append(name).append("<");
+        genExpression(TYPE_INT, true);
+        sb.append(") {\n");
+        indentation += INDENTATION;
+        depth--;
+        loopDepth++;
+        printIndentation().append(name).append("=").append(name).append("+");
+        genExpression(TYPE_INT, true);
+        sb.append(";\n");
+        genStatements();
+        loopDepth--;
+        depth++;
+        indentation -= INDENTATION;
+        printIndentation().append("}\n");
+        indentation -= INDENTATION;
+        printIndentation().append("}");
+        popVariables(currScopeStart);
+        currScopeStart = oldCSS;
+        return 0;
+    }
+
+    /**
+     * Generate a declaration statement.
+     * @return 0
+     */
+    public int genDecl() {
+        var type = getType();
+        var name = getVarName();
+        // Always make them mutable
+        sb.append(generateInvalid() ? getRandomName() : type.name).append(" !").append(name);
+        if (!(type instanceof TypeNullable) || random.nextBoolean()) {
+            sb.append("=");
+            genExpression(type, true);
+        }
+        sb.append(";");
+        addVariable(name, type);
+        return 0;
+    }
+
+    /**
+     * Generate an assignment statement.
+     * @return 0
+     */
+    public int genAssignment() {
+        Type type;
+        Type declared;
+        if (generateInvalid()) {
+            sb.append(getRandomName());
+            type = getType();
+            declared = type;
+        } else {
+            var v = findVisibleVariablesMatching(va->true);
+            if (v == null) return genDecl();
+            sb.append(v.name);
+            type = v.type;
+            declared = v.declared;
+        }
+        if (generateInvalid()) {
+            var name = getRandomName();
+            sb.append(".").append(name);
+            declared = getType();
+        } else if (type instanceof TypeStruct s && s.fields.length > 0 && random.nextBoolean()) {
+            var field = s.fields[random.nextInt(s.fields.length)];
+            sb.append(".").append(field.name);
+            declared = field.type;
+        }
+        sb.append("=");
+        genExpression(declared, true);
+        sb.append(";");
+        return 0;
+    }
+
+    /**
+     * Generate a return statement.
+     * @return FLAG_STOP
+     */
+    public int genReturn() {
+        var type = getType();
+        sb.append("return ");
+        genExpression(type, true);
+        sb.append(";");
+        return FLAG_STOP;
+    }
+
+    /**
+     * Generate a binary expression.
+     * This method does not care about operator precedence.
+     */
+    public void genExpression(Type type, boolean change) {
+        if (change && generateInvalid()) type = getType();
+        if (!(type instanceof TypeInt) && type != TYPE_FLT) {
+            genUnary(type, false);
+            return;
+        }
+        var num = randLog(MAX_BINARY_EXPRESSIONS_PER_EXPRESSION);
+        while(num-->0) {
+            genUnary(type, false);
+            sb.append(BINARY_OP[random.nextInt(BINARY_OP.length)]);
+        }
+        genUnary(type, false);
+    }
+
+    /**
+     * Generate a unary expression.
+     */
+    public void genUnary(Type type, boolean change) {
+        if (change && generateInvalid()) type = getType();
+        if (!(type instanceof TypeInt) && type != TYPE_FLT) {
+            genSuffix(type, false);
+            return;
+        }
+        var num = randLog(MAX_UNARY_EXPRESSIONS_PER_EXPRESSION);
+        while(num-->0) {
+            sb.append(UNARY_OP[random.nextInt(UNARY_OP.length)]);
+        }
+        genSuffix(type, false);
+    }
+
+    public TypeStruct.Field getField(Type type) {
+        int n=0;
+        for (var s: structs) {
+            for (var f: s.fields) {
+                if (f.type.isa(type)) n++;
+            }
+        }
+        if (n==0) return null;
+        n = random.nextInt(n);
+        for (var s: structs) {
+            for (var f: s.fields) {
+                if (f.type.isa(type)) if (n--==0) return f;
+            }
+        }
+        throw new AssertionError();
+    }
+
+    /**
+     * Generate
+     */
+    public void genSuffix(Type type, boolean change) {
+        genSuffixRecursive(type, change, MAX_SUFFIX_RECURSIVE_DEPTH);
+    }
+
+    public void genSuffixRecursive(Type type, boolean change, int depth) {
+        if (change && generateInvalid()) type = getType();
+        if (depth > 0 && random.nextBoolean()) {
+            if (generateInvalid()) {
+                var field = getRandomName();
+                var t = getType();
+                genSuffixRecursive(t, true, depth-1);
+                sb.append(".").append(field);
+                return;
+            } else {
+                var field = getField(type);
+                if (field != null) {
+                    genSuffixRecursive(field.struct, true, depth-1);
+                    sb.append(".").append(field.name);
+                    return;
+                }
+            }
+        }
+        genPrimary(type, false);
+    }
+
+    /**
+     * Generate a primary expression.
+     */
+    public void genPrimary(Type type, boolean change) {
+        if (change && generateInvalid()) type = getType();
+        var rand = random.nextInt(10);
+        if (rand == 0 && exprDepth != 0) {
+            sb.append("(");
+            exprDepth--;
+            genExpression(type, false);
+            exprDepth++;
+            sb.append(")");
+        } else if (rand < 6) {
+            genVariable(type);
+        } else {
+            genConst(type);
+        }
+    }
+
+    /**
+     * Generate a constant.
+     */
+    public void genConst(Type type) {
+        if (generateInvalid()) type = getType();
+        if (type instanceof TypeInt || (type == TYPE_FLT && random.nextBoolean())) {
+            var rand = random.nextInt(10);
+            switch (rand) {
+                case 0 -> sb.append("true");
+                case 1 -> sb.append("false");
+                default -> sb.append(random.nextInt(1<<(rand-2)));
+            }
+        } else if (type == TYPE_FLT) {
+            sb.append(random.nextFloat());
+        } else if (type instanceof TypeNullable n) {
+            if ((n.base instanceof TypeStruct s && s.fields == null) || random.nextBoolean()) {
+                sb.append("null");
+            } else {
+                sb.append("new ").append(generateInvalid() ? getRandomName() : n.base.name);
+            }
+        } else {
+            sb.append("new ").append(generateInvalid() ? getRandomName() : type.name);
+        }
+    }
+
+    /**
+     * Generate a variable. If there are none generate a number instead.
+     * If the program is allowed to be invalid a random name can be generated in some cases.
+     */
+    public void genVariable(Type type) {
+        if (generateInvalid()) {
+            sb.append(getRandomName());
+            return;
+        }
+        if (generateInvalid()) type = getType();
+        var t = type;
+        var v = findVisibleVariablesMatching(va->va.type.isa(t));
+        if (v == null) genConst(type);
+        else sb.append(v.name);
+    }
+
+}
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/progs/antiDep1.smp b/chapter22/src/test/java/com/seaofnodes/simple/progs/antiDep1.smp
new file mode 100644
index 00000000..b18dfd16
--- /dev/null
+++ b/chapter22/src/test/java/com/seaofnodes/simple/progs/antiDep1.smp
@@ -0,0 +1,11 @@
+// -*- mode: java;  -*-
+struct S { int f; };
+var v0 = new S;
+S? v1;
+if (arg) v1 = new S;
+if (v1) {
+    v0.f = v1.f;
+} else {
+    v0.f = 2;
+}
+return v0;
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/progs/arg_count.c b/chapter22/src/test/java/com/seaofnodes/simple/progs/arg_count.c
new file mode 100644
index 00000000..e247e28a
--- /dev/null
+++ b/chapter22/src/test/java/com/seaofnodes/simple/progs/arg_count.c
@@ -0,0 +1,10 @@
+#include <stdio.h>
+
+__attribute__ ((CALL_CONV))
+extern double addAll( long long i0, double f1, long long i2, double f3, long long i4, double f5, long long i6, double f7, long long i8, double f9, long long i10, double f11, long long i12, double f13, long long i14, double f15, long long i16, double f17, long long i18, double f19 );
+
+int main() {
+  double result = addAll( 0, 1.1, 2, 3.1, 4, 5.1, 6, 7.1, 8, 9.1, 10, 11.1, 12, 13.1, 14, 15.1, 16, 17.1, 18, 19.1 );
+  printf("%f\n", result);
+  return 0;
+}
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/progs/arg_count.smp b/chapter22/src/test/java/com/seaofnodes/simple/progs/arg_count.smp
new file mode 100644
index 00000000..6b6bc0ae
--- /dev/null
+++ b/chapter22/src/test/java/com/seaofnodes/simple/progs/arg_count.smp
@@ -0,0 +1,6 @@
+// -*- mode: java;  -*-
+val addAll = { int i0, flt f1, int i2, flt f3, int i4, flt f5, int i6, flt f7, int x8, flt f9, int i10, flt f11, int i12, flt f13, int i14, flt f15, int x16, flt f17 int x18, flt f19 ->
+    return
+    i0 + f1+ i2+ f3+ i4+ f5+ i6+ f7+ x8 +f9 +
+    i10+f11+i12+f13+i14+f15+x16+f17+x18+f19 ;
+};
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/progs/array1.smp b/chapter22/src/test/java/com/seaofnodes/simple/progs/array1.smp
new file mode 100644
index 00000000..6b10f92c
--- /dev/null
+++ b/chapter22/src/test/java/com/seaofnodes/simple/progs/array1.smp
@@ -0,0 +1,9 @@
+// -*- mode: java;  -*-
+int[] !ary = new int[arg];
+// Fill [0,1,2,3,4,...]
+for( int i=0; i<ary#; i++ )
+    ary[i] = i;
+// Fill [0,1,3,6,10,...]
+for( int i=0; i<ary#-1; i++ )
+    ary[i+1] += ary[i];
+return ary[1] * 1000 + ary[3]; // 1 * 1000 + 6
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/progs/brain_fuck.c b/chapter22/src/test/java/com/seaofnodes/simple/progs/brain_fuck.c
new file mode 100644
index 00000000..127cbe73
--- /dev/null
+++ b/chapter22/src/test/java/com/seaofnodes/simple/progs/brain_fuck.c
@@ -0,0 +1,18 @@
+#include <stdio.h>
+#include <stdbool.h>
+
+typedef struct AryInt {
+    unsigned int len;
+    unsigned char data[];
+} AryInt;
+
+__attribute__ ((CALL_CONV))
+extern AryInt* brain_fuck();
+
+int main() {
+  AryInt* ps = brain_fuck();
+
+  printf("%.*s", ps->len, ps->data);
+
+  return 0;
+}
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/progs/brain_fuck.smp b/chapter22/src/test/java/com/seaofnodes/simple/progs/brain_fuck.smp
new file mode 100644
index 00000000..ed90cb84
--- /dev/null
+++ b/chapter22/src/test/java/com/seaofnodes/simple/progs/brain_fuck.smp
@@ -0,0 +1,46 @@
+// -*- mode: java;  -*-
+val brain_fuck = { ->
+    u8[] !program = new u8[106];program[0] = 43;program[1] = 43;program[2] = 43;program[3] = 43;program[4] = 43;program[5] = 43;program[6] = 43;program[7] = 43;program[8] = 91;program[9] = 62;program[10] = 43;program[11] = 43;program[12] = 43;program[13] = 43;program[14] = 91;program[15] = 62;program[16] = 43;program[17] = 43;program[18] = 62;program[19] = 43;program[20] = 43;program[21] = 43;program[22] = 62;program[23] = 43;program[24] = 43;program[25] = 43;program[26] = 62;program[27] = 43;program[28] = 60;program[29] = 60;program[30] = 60;program[31] = 60;program[32] = 45;program[33] = 93;program[34] = 62;program[35] = 43;program[36] = 62;program[37] = 43;program[38] = 62;program[39] = 45;program[40] = 62;program[41] = 62;program[42] = 43;program[43] = 91;program[44] = 60;program[45] = 93;program[46] = 60;program[47] = 45;program[48] = 93;program[49] = 62;program[50] = 62;program[51] = 46;program[52] = 62;program[53] = 45;program[54] = 45;program[55] = 45;program[56] = 46;program[57] = 43;program[58] = 43;program[59] = 43;program[60] = 43;program[61] = 43;program[62] = 43;program[63] = 43;program[64] = 46;program[65] = 46;program[66] = 43;program[67] = 43;program[68] = 43;program[69] = 46;program[70] = 62;program[71] = 62;program[72] = 46;program[73] = 60;program[74] = 45;program[75] = 46;program[76] = 60;program[77] = 46;program[78] = 43;program[79] = 43;program[80] = 43;program[81] = 46;program[82] = 45;program[83] = 45;program[84] = 45;program[85] = 45;program[86] = 45;program[87] = 45;program[88] = 46;program[89] = 45;program[90] = 45;program[91] = 45;program[92] = 45;program[93] = 45;program[94] = 45;program[95] = 45;program[96] = 45;program[97] = 46;program[98] = 62;program[99] = 62;program[100] = 43;program[101] = 46;program[102] = 62;program[103] = 43;program[104] = 43;program[105] = 46;
+    int d = 0;
+    u8[] !output = new u8[0];
+    u8[] !data = new u8[100];
+
+    for( int pc = 0; pc < program#; pc++ ) {
+        var command = program[pc];
+        if (command == 62) {
+            d++;
+        } else if (command == 60) {
+            d--;
+        } else if (command == 43) {
+            data[d]++;
+        } else if (command == 45) {
+            data[d]--;
+        } else if (command == 46) {
+            // Output a byte; increase the output array size
+            var old = output;
+            output = new u8[output# + 1];
+            for( int i = 0; i < old#; i++ )
+                output[i] = old[i];
+            output[old#] = data[d]; // Add the extra byte on the end
+        } else if (command == 44) {
+            data[d] = 42;
+        } else if (command == 91) {
+            if (data[d] == 0) {
+                for( int d = 1; d > 0; ) {
+                    command = program[++pc];
+                    if (command == 91) d++;
+                    if (command == 93) d--;
+                }
+            }
+        } else if (command == 93) {
+            if (data[d]) {
+                for( int d = 1; d > 0; ) {
+                    command = program[--pc];
+                    if (command == 93) d++;
+                    if (command == 91) d--;
+                }
+            }
+        }
+    }
+    return output;
+};
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/progs/fib.c b/chapter22/src/test/java/com/seaofnodes/simple/progs/fib.c
new file mode 100644
index 00000000..263d2f13
--- /dev/null
+++ b/chapter22/src/test/java/com/seaofnodes/simple/progs/fib.c
@@ -0,0 +1,16 @@
+#include <stdio.h>
+#include <stdbool.h>
+
+
+__attribute__ ((CALL_CONV))
+extern int fib(int x);
+
+int main() {
+  printf("[");
+  for (int i = 0; i < 10; i++) {
+    printf("%d", fib(i));
+    if (i < 9) printf(", ");
+  }
+  printf("]");
+  return 0;
+}
\ No newline at end of file
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/progs/fib.smp b/chapter22/src/test/java/com/seaofnodes/simple/progs/fib.smp
new file mode 100644
index 00000000..1512541b
--- /dev/null
+++ b/chapter22/src/test/java/com/seaofnodes/simple/progs/fib.smp
@@ -0,0 +1,11 @@
+// -*- mode: java;  -*-
+val fib = {int n ->
+    int f1=1;
+    int f2=1;
+    while( n-- > 1 ){
+        int temp = f1+f2;
+        f1=f2;
+        f2=temp;
+    }
+    return f2;
+};
\ No newline at end of file
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/progs/jig.smp b/chapter22/src/test/java/com/seaofnodes/simple/progs/jig.smp
new file mode 100644
index 00000000..64c15dd7
--- /dev/null
+++ b/chapter22/src/test/java/com/seaofnodes/simple/progs/jig.smp
@@ -0,0 +1,2 @@
+// -*- mode: java;  -*-
+val allocIA = { int N -> return new u32[N]; };
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/progs/loop2.c b/chapter22/src/test/java/com/seaofnodes/simple/progs/loop2.c
new file mode 100644
index 00000000..934f2d89
--- /dev/null
+++ b/chapter22/src/test/java/com/seaofnodes/simple/progs/loop2.c
@@ -0,0 +1,7 @@
+
+__attribute__ ((CALL_CONV))
+extern int loop2();
+
+int main() {
+  return loop2();
+}
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/progs/loop2.smp b/chapter22/src/test/java/com/seaofnodes/simple/progs/loop2.smp
new file mode 100644
index 00000000..01ec827e
--- /dev/null
+++ b/chapter22/src/test/java/com/seaofnodes/simple/progs/loop2.smp
@@ -0,0 +1,10 @@
+// -*- mode: java;  -*-
+int i = 0;
+while(true) {
+    i += 1;
+    if( i==0 ) continue;
+    if( i==1 ) continue;
+    if( i==2 ) break;
+    continue;
+}
+return i;
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/progs/newtonFloat.c b/chapter22/src/test/java/com/seaofnodes/simple/progs/newtonFloat.c
new file mode 100644
index 00000000..7e7e796d
--- /dev/null
+++ b/chapter22/src/test/java/com/seaofnodes/simple/progs/newtonFloat.c
@@ -0,0 +1,16 @@
+#include <stdio.h>
+#include <math.h>
+#include <stdlib.h>
+
+extern double test_sqrt(double);
+
+int main( int argc, char** argv ) {
+  for( int i=0; i<10; i++ ) {
+    double d = test_sqrt((double)i), expect = sqrt((double)i);
+    double delta = fabs(d-expect);
+    printf("%d  %f   (%g)\n",i,d,delta);
+    if( delta > 1e-15 )
+      return 1;
+  }
+  return 0;
+}
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/progs/newtonFloat.smp b/chapter22/src/test/java/com/seaofnodes/simple/progs/newtonFloat.smp
new file mode 100644
index 00000000..be2dffec
--- /dev/null
+++ b/chapter22/src/test/java/com/seaofnodes/simple/progs/newtonFloat.smp
@@ -0,0 +1,12 @@
+// -*- mode: java;  -*-
+// Newtons approximation to the square root
+val test_sqrt = { flt x ->
+    flt epsilon = 1e-15;
+    flt guess = x;
+    while( 1 ) {
+        flt next = (x/guess + guess)/2;
+        if( guess-epsilon <= next & next <= guess+epsilon ) return guess;
+        //if( guess==next ) return guess;
+        guess = next;
+    }
+};
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/progs/no_stack_arg_count.smp b/chapter22/src/test/java/com/seaofnodes/simple/progs/no_stack_arg_count.smp
new file mode 100644
index 00000000..20a05445
--- /dev/null
+++ b/chapter22/src/test/java/com/seaofnodes/simple/progs/no_stack_arg_count.smp
@@ -0,0 +1,6 @@
+// -*- mode: java;  -*-
+val addAll = { int i0, flt f1, int i2, flt f3, int i4, flt f5, int i6, flt f7, int x8, flt f9, int i10, flt f11, int i12, flt f13, int i14, flt f15 ->
+    return
+    i0 + f1+ i2+ f3+ i4+ f5+ i6+ f7+ x8 +f9 +
+    i10+f11+i12+f13+i14+f15;
+};
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/progs/person.c b/chapter22/src/test/java/com/seaofnodes/simple/progs/person.c
new file mode 100644
index 00000000..df95e1ca
--- /dev/null
+++ b/chapter22/src/test/java/com/seaofnodes/simple/progs/person.c
@@ -0,0 +1,34 @@
+#include <stdio.h>
+#include <stdbool.h>
+#include <stdlib.h>
+
+typedef struct Person {
+    int age;
+} Person;
+
+typedef struct PersonArray {
+    unsigned int length;
+    int pad;
+    Person* data[];
+} PersonArray;
+
+__attribute__ ((CALL_CONV))
+extern void fcn(PersonArray* people, int index);
+
+int main() {
+    Person base[5] = {{25},{1},{18},{45},{60}};
+    unsigned char buf[8+8*5];
+    PersonArray* people_array = (PersonArray*)buf;
+    people_array->length=5;
+    for (int i=0; i<people_array->length; i++) people_array->data[i] = &base[i];
+
+    fcn(people_array, 1);
+    fcn(people_array, 1);
+    fcn(people_array, 1);
+    fcn(people_array, 1);
+    fcn(people_array, 1);
+
+    printf("%d\n", people_array->data[1]->age); // expected: 6
+
+    return 0;
+}
\ No newline at end of file
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/progs/person.smp b/chapter22/src/test/java/com/seaofnodes/simple/progs/person.smp
new file mode 100644
index 00000000..9f0f5bea
--- /dev/null
+++ b/chapter22/src/test/java/com/seaofnodes/simple/progs/person.smp
@@ -0,0 +1,9 @@
+// -*-java-*-
+struct Person {
+    int age;
+};
+
+val fcn = { Person?[] ps, int x ->
+    if( ps[x] )
+        ps[x].age++;
+};
\ No newline at end of file
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/progs/sieve.c b/chapter22/src/test/java/com/seaofnodes/simple/progs/sieve.c
new file mode 100644
index 00000000..cac4cfa3
--- /dev/null
+++ b/chapter22/src/test/java/com/seaofnodes/simple/progs/sieve.c
@@ -0,0 +1,19 @@
+#include <stdio.h>
+#include <stdbool.h>
+
+typedef struct AryInt {
+  unsigned int len;
+  unsigned int data[];
+} AryInt;
+
+__attribute__ ((CALL_CONV))
+extern AryInt *sieve(int N);
+
+int main() {
+  AryInt* ps = sieve(100);
+  printf("%d[",ps->len);
+  for( int i=0; i<ps->len; i++ )
+    printf("%d, ",ps->data[i]);
+  printf("]");
+  return 0;
+}
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/progs/sieve.smp b/chapter22/src/test/java/com/seaofnodes/simple/progs/sieve.smp
new file mode 100644
index 00000000..6d160b1e
--- /dev/null
+++ b/chapter22/src/test/java/com/seaofnodes/simple/progs/sieve.smp
@@ -0,0 +1,31 @@
+// -*- mode: java;  -*-
+// The main Sieve array
+val sieve = { int N ->
+    bool[] !ary = new bool[N];
+    // The primes less than N
+    u32[] !primes = new u32[N>>1];
+    // Number of primes so far, searching at index p
+    int nprimes = 0, p=2;
+    // Find primes while p^2 < N
+    while( p*p < N ) {
+        // skip marked non-primes
+        while( ary[p] ) p++;
+        // p is now a prime
+        primes[nprimes++] = p;
+        // Mark out the rest non-primes
+        for( int i = p + p; i < ary#; i+= p )
+            ary[i] = true;
+        p++;
+    }
+
+    // Now just collect the remaining primes, no more marking
+    for( ; p < N; p++ )
+        if( !ary[p] )
+            primes[nprimes++] = p;
+
+    // Copy/shrink the result array
+    u32[] !rez = new u32[nprimes];
+    for( int j=0; j < nprimes; j++ )
+        rez[j] = primes[j];
+    return rez;
+};
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/progs/sort.c b/chapter22/src/test/java/com/seaofnodes/simple/progs/sort.c
new file mode 100644
index 00000000..ad76cc7f
--- /dev/null
+++ b/chapter22/src/test/java/com/seaofnodes/simple/progs/sort.c
@@ -0,0 +1,28 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+// Test wrapper to call `sort.smp`
+
+typedef struct AryInt {
+    unsigned int len;
+    long long data[];
+} AryInt;
+
+__attribute__ ((CALL_CONV))
+extern AryInt* merge_sort(AryInt*);
+
+
+long long primes[] = { 25, 97, 89, 83, 79, 73, 71, 67, 61, 59, 53, 47, 43, 41, 37, 31, 29, 23, 19, 17, 13, 11, 7, 5, 3, 2 };
+
+int main() {
+  AryInt *as = (AryInt*)primes;
+
+  merge_sort(as);
+
+  printf("%d[",as->len);
+  for( int i=0; i<as->len; i++ )
+    printf("%d, ",as->data[i]);
+  printf("]");
+
+  return 0;
+}
\ No newline at end of file
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/progs/sort.smp b/chapter22/src/test/java/com/seaofnodes/simple/progs/sort.smp
new file mode 100644
index 00000000..ae3f4f23
--- /dev/null
+++ b/chapter22/src/test/java/com/seaofnodes/simple/progs/sort.smp
@@ -0,0 +1,38 @@
+// -*- mode: java;  -*-
+// based on the top-down version from https://en.wikipedia.org/wiki/Merge_sort
+
+val merge_sort = { int[] a ->
+    int[] !b = new int[a#];
+    copy_array (a, 0, a#, b);
+    split_merge(a, 0, a#, b);
+};
+
+val split_merge = { int[] b, int begin, int end, int[] a ->
+    if (end - begin <= 1)
+        return 0;
+    int middle = (end + begin) / 2;
+    split_merge(a, begin, middle, b);
+    split_merge(a, middle, end, b);
+    merge(b, begin, middle, end, a);
+    return 0;
+};
+
+val merge = { int[] b, int begin, int middle, int end, int[] a ->
+    int i = begin, j = middle;
+
+    for (int k = begin; k < end; k++) {
+        // && and ||
+        bool cond = false;
+        if (i < middle) {
+            if (j >= end)          cond = true;
+            else if (a[i] <= a[j]) cond = true;
+        }
+        if (cond) b[k] = a[i++];
+        else      b[k] = a[j++];
+    }
+};
+
+val copy_array = { int[] a, int begin, int end, int[] b ->
+    for (int k = begin; k < end; k++)
+        b[k] = a[k];
+};
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/progs/stringHash.c b/chapter22/src/test/java/com/seaofnodes/simple/progs/stringHash.c
new file mode 100644
index 00000000..2c6d0fa9
--- /dev/null
+++ b/chapter22/src/test/java/com/seaofnodes/simple/progs/stringHash.c
@@ -0,0 +1,30 @@
+#include <stdio.h>
+#include <stdbool.h>
+
+typedef struct ArrayU8 {
+  unsigned int length;
+  unsigned char data[];
+} ArrayU8;
+typedef struct String {
+  ArrayU8 * cs;
+  long long _hashCode;
+} String;
+
+
+__attribute__ ((CALL_CONV))
+extern bool equals(String*st1, String*st2);
+
+int main() {
+  String test1 = {.cs=(ArrayU8*)"\x04\x00\x00\x00test"};
+  String test2 = {.cs=(ArrayU8*)"\x05\x00\x00\x00test1"};
+
+  if( equals(&test1, &test2) ) {
+    printf("Expected test1 and test2 unequal");
+    return 1;
+  }
+  if( !equals(&test2, &test2) ) {
+    printf("Expected test2 and test2 equal");
+    return 1;
+  }
+  return 0;
+}
diff --git a/chapter22/src/test/java/com/seaofnodes/simple/progs/stringHash.smp b/chapter22/src/test/java/com/seaofnodes/simple/progs/stringHash.smp
new file mode 100644
index 00000000..dafa7456
--- /dev/null
+++ b/chapter22/src/test/java/com/seaofnodes/simple/progs/stringHash.smp
@@ -0,0 +1,31 @@
+// -*- mode: java;  -*-
+struct String {
+    u8[] cs;
+    int _hashCode;
+};
+
+// Compare two Strings
+val equals = { String self, String s ->
+    if( self == s ) return true;
+    if( self.cs# != s.cs# ) return false;
+    for( int i=0; i< self.cs#; i++ )
+        if( self.cs[i] != s.cs[i] )
+            return false;
+    return true;
+};
+
+// Return the String hashCode (cached, and never 0)
+val hashCode = { String self ->
+    self._hashCode
+    ?  self._hashCode
+    : (self._hashCode = _hashCodeString(self));
+};
+
+val _hashCodeString = { String self ->
+    int hash=0;
+    if( self.cs )
+        for( int i=0; i< self.cs#; i++ )
+            hash = hash*31 + self.cs[i];
+    if( !hash ) hash = 123456789;
+    return hash;
+};
-- 
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