[MPlayer-dev-eng] cpuid vs 386 vs 486

[Michael Niedermayer]

Hi

On Tuesday 05 February 2002 22:28, Arpi wrote:
> Hi,
>
> it probably uses BSWAP. It's specific to 486+ cpus, and common in these
> codecs.
bswap.h:
---------------------------------
inline static unsigned int ByteSwap32(unsigned int x)
{
#if __CPU__ > 386
 __asm("bswap	%0":
      "=r" (x)     :
#else
 __asm("xchgb	%b0,%h0\n"
      "	rorl	$16,%0\n"
      "	xchgb	%b0,%h0":
      "=q" (x)		:
#endif
      "0" (x));
  return x;
}
----------------------------------
so it wont work if its compiled on 486+ and executed on 386
runtime cpudetect detect is imho not worth it here, and would have a serious 
impact on performance as this is used in the bitstream reader which is called 
alot

[...]
Michael