libavcodec/i386/cpuid.c

   1 /*
   2  * CPU detection code, extracted from mmx.h
   3  * (c)1997-99 by H. Dietz and R. Fisher
   4  * Converted to C and improved by Fabrice Bellard.
   5  *
   6  * This file is part of FFmpeg.
   7  *
   8  * FFmpeg is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License as published by the Free Software Foundation; either
  11  * version 2.1 of the License, or (at your option) any later version.
  12  *
  13  * FFmpeg is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  * Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with FFmpeg; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  21  */
  22
  23 #include <stdlib.h>
  24 #include "libavutil/x86_cpu.h"
  25 #include "libavcodec/dsputil.h"
  26
  27 #undef printf
  28
  29 /* ebx saving is necessary for PIC. gcc seems unable to see it alone */
  30 #define cpuid(index,eax,ebx,ecx,edx)\
  31     asm volatile\
  32         ("mov %%"REG_b", %%"REG_S"\n\t"\
  33          "cpuid\n\t"\
  34          "xchg %%"REG_b", %%"REG_S\
  35          : "=a" (eax), "=S" (ebx),\
  36            "=c" (ecx), "=d" (edx)\
  37          : "0" (index));
  38
  39 /* Function to test if multimedia instructions are supported...  */
  40 int mm_support(void)
  41 {
  42     int rval = 0;
  43     int eax, ebx, ecx, edx;
  44     int max_std_level, max_ext_level, std_caps=0, ext_caps=0;
  45     x86_reg a, c;
  46
  47     asm volatile (
  48         /* See if CPUID instruction is supported ... */
  49         /* ... Get copies of EFLAGS into eax and ecx */
  50         "pushf\n\t"
  51         "pop %0\n\t"
  52         "mov %0, %1\n\t"
  53
  54         /* ... Toggle the ID bit in one copy and store */
  55         /*     to the EFLAGS reg */
  56         "xor $0x200000, %0\n\t"
  57         "push %0\n\t"
  58         "popf\n\t"
  59
  60         /* ... Get the (hopefully modified) EFLAGS */
  61         "pushf\n\t"
  62         "pop %0\n\t"
  63         : "=a" (a), "=c" (c)
  64         :
  65         : "cc"
  66         );
  67
  68     if (a == c)
  69         return 0; /* CPUID not supported */
  70
  71     cpuid(0, max_std_level, ebx, ecx, edx);
  72
  73     if(max_std_level >= 1){
  74         cpuid(1, eax, ebx, ecx, std_caps);
  75         if (std_caps & (1<<23))
  76             rval |= FF_MM_MMX;
  77         if (std_caps & (1<<25))
  78             rval |= FF_MM_MMXEXT
  79 #if !defined(__GNUC__) || __GNUC__ > 2
  80                   | FF_MM_SSE;
  81         if (std_caps & (1<<26))
  82             rval |= FF_MM_SSE2;
  83         if (ecx & 1)
  84             rval |= FF_MM_SSE3;
  85         if (ecx & 0x00000200 )
  86             rval |= FF_MM_SSSE3
  87 #endif
  88                   ;
  89     }
  90
  91     cpuid(0x80000000, max_ext_level, ebx, ecx, edx);
  92
  93     if(max_ext_level >= 0x80000001){
  94         cpuid(0x80000001, eax, ebx, ecx, ext_caps);
  95         if (ext_caps & (1<<31))
  96             rval |= FF_MM_3DNOW;
  97         if (ext_caps & (1<<30))
  98             rval |= FF_MM_3DNOWEXT;
  99         if (ext_caps & (1<<23))
 100             rval |= FF_MM_MMX;
 101         if (ext_caps & (1<<22))
 102             rval |= FF_MM_MMXEXT;
 103     }
 104
 105 #if 0
 106     av_log(NULL, AV_LOG_DEBUG, "%s%s%s%s%s%s%s%s\n",
 107         (rval&FF_MM_MMX) ? "MMX ":"",
 108         (rval&FF_MM_MMXEXT) ? "MMX2 ":"",
 109         (rval&FF_MM_SSE) ? "SSE ":"",
 110         (rval&FF_MM_SSE2) ? "SSE2 ":"",
 111         (rval&FF_MM_SSE3) ? "SSE3 ":"",
 112         (rval&FF_MM_SSSE3) ? "SSSE3 ":"",
 113         (rval&FF_MM_3DNOW) ? "3DNow ":"",
 114         (rval&FF_MM_3DNOWEXT) ? "3DNowExt ":"");
 115 #endif
 116     return rval;
 117 }
 118
 119 #ifdef TEST
 120 int main ( void )
 121 {
 122     int mm_flags;
 123     mm_flags = mm_support();
 124     printf("mm_support = 0x%08X\n",mm_flags);
 125     return 0;
 126 }
 127 #endif