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emit_x64_data_processing: Reduce codesize of LogicalShiftLeft32 for carry case

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MerryMage 2021-04-26 20:36:59 +01:00
parent 510862e50c
commit 58ff457339
1 changed files with 9 additions and 26 deletions
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35
src/backend/x64/emit_x64_data_processing.cpp
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@ -355,36 +355,19 @@ void EmitX64::EmitLogicalShiftLeft32(EmitContext& ctx, IR::Inst* inst) {
ctx.EraseInstruction(carry_inst);
ctx.reg_alloc.DefineValue(inst, result);
} else {
ctx.reg_alloc.Use(shift_arg, HostLoc::RCX);
ctx.reg_alloc.UseScratch(shift_arg, HostLoc::RCX);
const Xbyak::Reg32 result = ctx.reg_alloc.UseScratchGpr(operand_arg).cvt32();
const Xbyak::Reg32 tmp = ctx.reg_alloc.ScratchGpr().cvt32();
const Xbyak::Reg32 carry = ctx.reg_alloc.UseScratchGpr(carry_arg).cvt32();
// TODO: Optimize this.
code.inLocalLabel();
code.cmp(code.cl, 32);
code.ja(".Rs_gt32");
code.je(".Rs_eq32");
// if (Rs & 0xFF < 32) {
code.bt(carry.cvt32(), 0); // Set the carry flag for correct behaviour in the case when Rs & 0xFF == 0
code.shl(result, code.cl);
code.mov(tmp, 63);
code.cmp(code.cl, 63);
code.cmova(code.ecx, tmp);
code.shl(result.cvt64(), 32);
code.bt(carry.cvt32(), 0);
code.shl(result.cvt64(), code.cl);
code.setc(carry.cvt8());
code.jmp(".end");
// } else if (Rs & 0xFF > 32) {
code.L(".Rs_gt32");
code.xor_(result, result);
code.xor_(carry, carry);
code.jmp(".end");
// } else if (Rs & 0xFF == 32) {
code.L(".Rs_eq32");
code.mov(carry, result);
code.and_(carry, 1);
code.xor_(result, result);
// }
code.L(".end");
code.outLocalLabel();
code.shr(result.cvt64(), 32);
ctx.reg_alloc.DefineValue(carry_inst, carry);
ctx.EraseInstruction(carry_inst);