2 files changed, 13 insertions, 0 deletions
diff --git a/isa/src/main/java/com/seaofnodes/isa/Arm64.java b/isa/src/main/java/com/seaofnodes/isa/Arm64.java
index ce7f7b11..5edb2f3c 100644
--- a/isa/src/main/java/com/seaofnodes/isa/Arm64.java
+++ b/isa/src/main/java/com/seaofnodes/isa/Arm64.java
@@ -4,6 +4,12 @@ package com.seaofnodes.isa;
 public final class Arm64 {
     private Arm64() {}
 
+    // MRS Xt,NZCV / MSR NZCV,Xt. Register 31 denotes XZR.
+    public static int flags(int reg, boolean toFlags) {
+        assert 0<=reg && reg<32;
+        return (toFlags ? 0xD51B4200 : 0xD53B4200) | reg;
+    }
+
     public static final int OP_ADD       = 0b10_001_011;
     public static final int OPF_ADD      = 0b00_011_110;
     public static final int OPF_OP_ADD   = 0b00_101_0;
diff --git a/isa/src/main/java/com/seaofnodes/isa/X86.java b/isa/src/main/java/com/seaofnodes/isa/X86.java
index 78fa3da5..d5150a31 100644
--- a/isa/src/main/java/com/seaofnodes/isa/X86.java
+++ b/isa/src/main/java/com/seaofnodes/isa/X86.java
@@ -162,11 +162,18 @@ public final class X86 {
         }
     }
     public static void flags(CodeSink out, int reg, boolean toFlags) {
+        assert 0<=reg && reg<16 && reg!=4;
         if( !toFlags ) out.add1(0x9C); // PUSHF
         rexF(0,reg,-1,false,out);
         out.add1((toFlags ? 0x50 : 0x58)+(reg&7));
         if( toFlags ) out.add1(0x9D); // POPF
     }
+    public static void flagsStack(CodeSink out, int offset, boolean toFlags) {
+        if( !toFlags ) out.add1(0x9C); // PUSHFQ
+        // POP's destination uses the restored RSP, so offset needs no adjustment.
+        memory(out,0,toFlags ? 0xFF : 0x8F,false,toFlags ? 6 : 0,4,-1,offset,0);
+        if( toFlags ) out.add1(0x9D); // POPFQ
+    }
     public static void stackCopy(CodeSink out, int srcOffset, int dstOffset) {
         memory(out,0,0xFF,false,6,4,-1,srcOffset,0); // PUSH [rsp+srcOffset]
         memory(out,0,0x8F,false,0,4,-1,dstOffset,0); // POP uses the restored rsp.