From 45bd2e5fae4cbbee0ddd07094755c2f995178f28 Mon Sep 17 00:00:00 2001 From: Cliff Click Date: Sat, 19 Sep 2026 19:49:46 -0700 Subject: Fix ch21 MulIX86 encoding --- .../simple/node/cpus/x86_64_v2/MulIX86.java | 36 +++++++++++++++++++--- 1 file changed, 31 insertions(+), 5 deletions(-) (limited to 'chapter21') diff --git a/chapter21/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/MulIX86.java b/chapter21/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/MulIX86.java index a9a83fb7..3c00b2e8 100644 --- a/chapter21/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/MulIX86.java +++ b/chapter21/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/MulIX86.java @@ -1,11 +1,37 @@ package com.seaofnodes.simple.node.cpus.x86_64_v2; -import com.seaofnodes.simple.node.Node; +import com.seaofnodes.simple.SB; +import com.seaofnodes.simple.node.*; +import com.seaofnodes.simple.codegen.*; -public class MulIX86 extends ImmX86 { - MulIX86( Node add, int imm ) { super(add,imm); } +public class MulIX86 extends MachConcreteNode implements MachNode { + final int _imm; + MulIX86( Node mul, int imm ) { + super(mul); + _inputs.pop(); // Pop the constant input + _imm = imm; // Record the constant + } @Override public String op() { return "muli"; } @Override public String glabel() { return "*"; } - @Override int opcode() { return 0x69; } - @Override int mod() { return 0; } + @Override public RegMask regmap(int i) { return x86_64_v2.RMASK; } + @Override public RegMask outregmap() { return x86_64_v2.WMASK; } + // Retain Chapter 21's allocation contract: output is also input #1. + @Override public int twoAddress() { return 1; } + + // IMUL encodes a destination register, unlike ImmX86's opcode extension. + @Override public final void encoding( Encoding enc ) { + short dst = enc.reg(this ); // Also src1 in this chapter + short src = enc.reg(in(1)); + enc.add1(x86_64_v2.rex(dst, src, 0)); + // opcode; 0x69 or 0x6B + enc.add1( 0x69 + (x86_64_v2.imm8(_imm) ? 2 : 0) ); + enc.add1( x86_64_v2.modrm(x86_64_v2.MOD.DIRECT, dst, src) ); + // immediate(4 bytes) 32 bits or (1 byte)8 bits + if( x86_64_v2.imm8(_imm) ) enc.add1(_imm); + else enc.add4(_imm); + } + // General form: "muli dst = src * #imm" + @Override public void asm(CodeGen code, SB sb) { + sb.p(code.reg(this)).p(" = ").p(code.reg(in(1))).p(" * #").p(_imm); + } } -- cgit v1.2.3