Displaying 3 results from an estimated 3 matches for "tsetc".
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setc
2013 Jul 14
0
[LLVMdev] [PATCH] x86/asm: avoid mnemonics without type suffix
.... Nada. None. The semantics are *exactly* the same for btl and btq
> in this case, so why would you want the user to specify one or the
> other?
I don't think you've actually tested that, have you? (x86-64)
int main() {
long val = 0xffffffff;
char res;
asm("btl $63, %1\n\tsetc %0" : "=r"(res) : "m"(val));
printf("%d\n", res);
asm("btq $63, %1\n\tsetc %0" : "=r"(res) : "m"(val));
printf("%d\n", res);
}
Tim.
2013 Jul 14
2
[LLVMdev] [PATCH] x86/asm: avoid mnemonics without type suffix
On Sun, Jul 14, 2013 at 11:35 AM, Tim Northover <t.p.northover at gmail.com> wrote:
>
> I'm coming at this from the compiler side, where the register form is
> unambiguous and not questioned. The discussion we're having involves
> only the immediate form of the instruction. GNU as interprets:
>
> bt $63, mem
>
> as
> btl $63, mem
>
> which may
2013 Jul 14
2
[LLVMdev] [PATCH] x86/asm: avoid mnemonics without type suffix
Hi,
The issue perhaps wasn't explained ideally (and possibly shouldn't
have been CCed directly to you either, so apologies, but now that
there *is* a discussion...)
> Try some actual relevant test instead:
>
> bt %eax,mem
> bt %rax,mem
>
> and notice how they are actually fundamentally different. Test-case:
I'm coming at this from the compiler side, where the