diff --git a/src/core/cpu_patches.cpp b/src/core/cpu_patches.cpp index 0160d63a3..f31ff18cb 100644 --- a/src/core/cpu_patches.cpp +++ b/src/core/cpu_patches.cpp @@ -345,9 +345,26 @@ static void GenerateBLSMSK(const ZydisDecodedOperand* operands, Xbyak::CodeGener SaveRegisters(c, {scratch}); + Xbyak::Label set_carry, clear_carry, end; + + // BLSMSK sets CF to zero if source is NOT zero, otherwise it sets CF to one. c.mov(scratch, *src); + c.test(scratch, scratch); + c.jz(set_carry); + c.jmp(clear_carry); + + c.L(set_carry); c.dec(scratch); c.xor_(scratch, *src); + c.stc(); + c.jmp(end); + + c.L(clear_carry); + c.dec(scratch); + c.xor_(scratch, *src); + // We don't need to clear carry here since XOR does that for us + + c.L(end); c.mov(dst, scratch); RestoreRegisters(c, {scratch}); @@ -361,9 +378,26 @@ static void GenerateBLSR(const ZydisDecodedOperand* operands, Xbyak::CodeGenerat SaveRegisters(c, {scratch}); + Xbyak::Label set_carry, clear_carry, end; + + // BLSR sets CF to zero if source is NOT zero, otherwise it sets CF to one. c.mov(scratch, *src); + c.test(scratch, scratch); + c.jz(set_carry); + c.jmp(clear_carry); + + c.L(set_carry); c.dec(scratch); c.and_(scratch, *src); + c.stc(); + c.jmp(end); + + c.L(clear_carry); + c.dec(scratch); + c.and_(scratch, *src); + // We don't need to clear carry here since AND does that for us + + c.L(end); c.mov(dst, scratch); RestoreRegisters(c, {scratch});