[squeak-dev] x86 sarl curiosity...
Martin Beck
martin.beck at hpi.uni-potsdam.de
Wed Jan 21 19:06:18 UTC 2009
Hi Eliot,
Eliot Miranda wrote:
> Hi All,
> anyone know the x86/IA32 really well? If so, read on. Otherwise save
> yourself the yawn.
>
[...]
> (my emphasis added). But neither the Bochs simulator nor my Intel Core Duo
> set the flags when doing sarl $1, %eax when %eax contains -1. Have I
> misread, or is the manual wrong?
>
I cannot confirm this. Using this simple C-Program:
int calc(int i) {
return i >> 1;
}
int main() {
printf("%i\n", calc(-1));
}
my GCC 4.3.2 generates a sarl %eax instruction as the assembler output
shows. Debugging it with Kdbg shows a change of the flags after the
instruction. In fact, CF and SF are set as (more or less) expected. I
also have a Intel Core 2 Duo.
Regards,
Martin
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