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ffmpeg / libavcodec / i386 / cputest.c @ e42a152b

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/* Cpu detection code, extracted from mmx.h ((c)1997-99 by H. Dietz
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   and R. Fisher). Converted to C and improved by Fabrice Bellard */
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#include <stdlib.h>
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#include "../dsputil.h"
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#ifdef ARCH_X86_64
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#  define REG_b "rbx"
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#  define REG_S "rsi"
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#else
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#  define REG_b "ebx"
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#  define REG_S "esi"
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#endif
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/* ebx saving is necessary for PIC. gcc seems unable to see it alone */
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#define cpuid(index,eax,ebx,ecx,edx)\
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    __asm __volatile\
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        ("mov %%"REG_b", %%"REG_S"\n\t"\
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         "cpuid\n\t"\
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         "xchg %%"REG_b", %%"REG_S\
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         : "=a" (eax), "=S" (ebx),\
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           "=c" (ecx), "=d" (edx)\
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         : "0" (index));
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/* Function to test if multimedia instructions are supported...  */
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int mm_support(void)
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{
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    int rval = 0;
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    int eax, ebx, ecx, edx;
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    int max_std_level, max_ext_level, std_caps=0, ext_caps=0;
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    long a, c;
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    __asm__ __volatile__ (
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                          /* See if CPUID instruction is supported ... */
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                          /* ... Get copies of EFLAGS into eax and ecx */
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                          "pushf\n\t"
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                          "pop %0\n\t"
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                          "mov %0, %1\n\t"
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                          /* ... Toggle the ID bit in one copy and store */
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                          /*     to the EFLAGS reg */
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                          "xor $0x200000, %0\n\t"
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                          "push %0\n\t"
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                          "popf\n\t"
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                          /* ... Get the (hopefully modified) EFLAGS */
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                          "pushf\n\t"
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                          "pop %0\n\t"
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                          : "=a" (a), "=c" (c)
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                          :
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                          : "cc" 
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                          );
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    if (a == c)
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        return 0; /* CPUID not supported */
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    cpuid(0, max_std_level, ebx, ecx, edx);
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    if(max_std_level >= 1){
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        cpuid(1, eax, ebx, ecx, std_caps);
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        if (std_caps & (1<<23))
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            rval |= MM_MMX;
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        if (std_caps & (1<<25)) 
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            rval |= MM_MMXEXT | MM_SSE;
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        if (std_caps & (1<<26)) 
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            rval |= MM_SSE2;
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    }
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    cpuid(0x80000000, max_ext_level, ebx, ecx, edx);
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    if(max_ext_level >= 0x80000001){
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        cpuid(0x80000001, eax, ebx, ecx, ext_caps);
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        if (ext_caps & (1<<31))
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            rval |= MM_3DNOW;
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        if (ext_caps & (1<<30))
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            rval |= MM_3DNOWEXT;
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        if (ext_caps & (1<<23))
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            rval |= MM_MMX;
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    }
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    cpuid(0, eax, ebx, ecx, edx);
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    if (       ebx == 0x68747541 &&
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               edx == 0x69746e65 &&
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               ecx == 0x444d4163) {
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        /* AMD */
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        if(ext_caps & (1<<22))
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            rval |= MM_MMXEXT;
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    } else if (ebx == 0x746e6543 &&
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               edx == 0x48727561 &&
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               ecx == 0x736c7561) {  /*  "CentaurHauls" */
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        /* VIA C3 */
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        if(ext_caps & (1<<24))
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          rval |= MM_MMXEXT;
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    } else if (ebx == 0x69727943 &&
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               edx == 0x736e4978 &&
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               ecx == 0x64616574) {
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        /* Cyrix Section */
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        /* See if extended CPUID level 80000001 is supported */
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        /* The value of CPUID/80000001 for the 6x86MX is undefined
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           according to the Cyrix CPU Detection Guide (Preliminary
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           Rev. 1.01 table 1), so we'll check the value of eax for
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           CPUID/0 to see if standard CPUID level 2 is supported.
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           According to the table, the only CPU which supports level
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           2 is also the only one which supports extended CPUID levels.
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        */
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        if (eax < 2) 
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            return rval;
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        if (ext_caps & (1<<24))
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            rval |= MM_MMXEXT;
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    }
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#if 0
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    av_log(NULL, AV_LOG_DEBUG, "%s%s%s%s%s%s\n", 
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        (rval&MM_MMX) ? "MMX ":"", 
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        (rval&MM_MMXEXT) ? "MMX2 ":"", 
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        (rval&MM_SSE) ? "SSE ":"", 
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        (rval&MM_SSE2) ? "SSE2 ":"", 
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        (rval&MM_3DNOW) ? "3DNow ":"", 
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        (rval&MM_3DNOWEXT) ? "3DNowExt ":"");
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#endif
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    return rval;
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}
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#ifdef __TEST__
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int main ( void )
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{
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  int mm_flags;
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  mm_flags = mm_support();
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  printf("mm_support = 0x%08X\n",mm_flags);
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  return 0;
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}
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#endif