[FFmpeg-devel] [PATCH]Use pushfl/popfl in cpuid.c

[Reimar Döffinger]

On Mon, Nov 24, 2008 at 12:20:35PM -0000, M?ns Rullg?rd wrote:
> >> > How about
> >> > #ifdef ARCH_X86_64
> >> > #define PUSHF "pushfq\n\t"
> >> > #define POPF  "popfq\n\t"
> >> > #else
> >> > #define PUSHF "pushfl\n\t"
> >> > #define POPF  "popfl\n\t"
> >> > #endif
> >> > ?
> >>
> >> Just make sure you test it on both.
> >
> > Attached patch seems to work fine on x86_64 (make test passes).
> 
> Does it detect the cpuid/simd support correctly?  make test would pass
> even if it didn't.

Oh well, let's just do this the easy way:
cpuid.o after patch:
0000000000000000 <mm_support>:
   0:   9c                      pushfq 
   1:   58                      pop    %rax
   2:   48 89 c1                mov    %rax,%rcx
   5:   48 35 00 00 20 00       xor    $0x200000,%rax
   b:   50                      push   %rax
   c:   9d                      popfq  
   d:   9c                      pushfq 
   e:   58                      pop    %rax
   f:   45 31 c0                xor    %r8d,%r8d
  12:   48 39 c8                cmp    %rcx,%rax
  15:   0f 84 b7 00 00 00       je     d2 <mm_support+0xd2>
  1b:   31 c0                   xor    %eax,%eax
  1d:   48 89 de                mov    %rbx,%rsi
  20:   0f a2                   cpuid  


cpuid.o before patch:
0000000000000000 <mm_support>:
   0:   9c                      pushfq 
   1:   58                      pop    %rax
   2:   48 89 c1                mov    %rax,%rcx
   5:   48 35 00 00 20 00       xor    $0x200000,%rax
   b:   50                      push   %rax
   c:   9d                      popfq  
   d:   9c                      pushfq 
   e:   58                      pop    %rax
   f:   45 31 c0                xor    %r8d,%r8d
  12:   48 39 c8                cmp    %rcx,%rax
  15:   0f 84 b7 00 00 00       je     d2 <mm_support+0xd2>
  1b:   31 c0                   xor    %eax,%eax
  1d:   48 89 de                mov    %rbx,%rsi
  20:   0f a2                   cpuid  

Both compiled with gcc (Gentoo 4.3.2 p1.0) 4.3.2
Output of cpuid.c compiled with -DTEST:
mm_support = 0x0000007F
(corresponding to
FF_MM_MMX | FF_MM_MMXEXT | FF_MM_3DNOW | FF_MM_SSE | FF_MM_SSE2 | FF_MM_3DNOWEXT | FF_MM_SSE3
)

Greetings,
Reimar D?ffinger