Set CF correctly on BLSR patch

This commit is contained in:
offtkp 2024-09-02 02:20:29 +03:00
parent 101aeb920d
commit afcdd26948

View file

@ -339,9 +339,26 @@ 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});