[FFmpeg-devel] [FFmpeg-cvslog] r12171 - trunk/doc/optimization.txt

[İsmail Dönmez]

Hi,

On Thu, Feb 21, 2008 at 10:10 PM, Reimar D?ffinger
<Reimar.Doeffinger at stud.uni-karlsruhe.de> wrote:
> On Thu, Feb 21, 2008 at 09:51:53PM +0200, ?smail D?nmez wrote:
>  > >  Not asm, but maybe someone is motivated to test this with a up-to-date
>  > >  gcc on some 32 bit system:
>  > >  > #include <inttypes.h>
>  > >  > uint64_t a;
>  > >  > uint16_t b;
>  > >  > uint64_t mul(void) {
>  > >  >   return a * b;
>  > >  > }
>  >
>  >
>  > gcc 4.4 trunk produces :
>  >
>  >       movq    _b at GOTPCREL(%rip), %rax
>  >       movzwl  (%rax), %eax
>  >       movzwl  %ax, %edx
>  >       movq    _a at GOTPCREL(%rip), %rax
>  >       movq    (%rax), %rax
>  >       imulq   %rdx, %rax
>  >       leave
>  >       ret
>
>  I am fairly certain that not even gcc < 3 managed to get that wrong on a
>  _64-bit_ system...

Also note tha gcc 4.4 trunk is basically 4.3 now. So we might note
that gcc 4.3 is good enough but ffmpeg supports gcc 2.x still.



-- 
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