mpeg2enc/cpu_accel.c

   1 /*
   2  * cpu_accel.c
   3  * Copyright (C) 1999-2000 Aaron Holtzman <aholtzma@ess.engr.uvic.ca>
   4  *
   5  * This file is part of mpeg2dec, a free MPEG-2 video stream decoder.
   6  *
   7  * mpeg2dec is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * mpeg2dec is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  20  */
  21
  22 #include <stdio.h>
  23 #include <inttypes.h>
  24
  25 #include "cpu_accel.h"
  26
  27 #ifdef X86_CPU
  28 static int x86_accel (void)
  29 {
  30     int eax, ebx, ecx, edx;
  31     int AMD;
  32     int caps;
  33
  34 #define cpuid(op,eax,ebx,ecx,edx)       \
  35     asm ("cpuid"                        \
  36          : "=a" (eax),                  \
  37            "=b" (ebx),                  \
  38            "=c" (ecx),                  \
  39            "=d" (edx)                   \
  40          : "a" (op)                     \
  41          : "cc")
  42
  43     asm ("pushfl\n\t"
  44          "popl %0\n\t"
  45          "movl %0,%1\n\t"
  46          "xorl $0x200000,%0\n\t"
  47          "pushl %0\n\t"
  48          "popfl\n\t"
  49          "pushfl\n\t"
  50          "popl %0"
  51          : "=a" (eax),
  52            "=b" (ebx)
  53          :
  54          : "cc");
  55
  56     if (eax == ebx)             // no cpuid
  57         return 0;
  58
  59     cpuid (0x00000000, eax, ebx, ecx, edx);
  60     if (!eax)                   // vendor string only
  61         return 0;
  62
  63     AMD = (ebx == 0x68747541) && (ecx == 0x444d4163) && (edx == 0x69746e65);
  64
  65     cpuid (0x00000001, eax, ebx, ecx, edx);
  66     if (! (edx & 0x00800000))   // no MMX
  67         return 0;
  68
  69     caps = ACCEL_X86_MMX;
  70     if (edx & 0x02000000)       // SSE - identical to AMD MMX extensions
  71         caps = ACCEL_X86_MMX | ACCEL_X86_MMXEXT;
  72
  73     cpuid (0x80000000, eax, ebx, ecx, edx);
  74     if (eax < 0x80000001)       // no extended capabilities
  75         return caps;
  76
  77     cpuid (0x80000001, eax, ebx, ecx, edx);
  78
  79     if (edx & 0x80000000)
  80         caps |= ACCEL_X86_3DNOW;
  81
  82     if (AMD && (edx & 0x00400000))      // AMD MMX extensions
  83         {
  84                 caps |= ACCEL_X86_MMXEXT;
  85         }
  86
  87     return caps;
  88 }
  89 #endif
  90
  91 int cpu_accel (void)
  92 {
  93 #ifdef X86_CPU
  94     static int got_accel = 0;
  95     static int accel;
  96
  97     if (!got_accel) {
  98         got_accel = 1;
  99         accel = x86_accel ();
 100     }
 101
 102     return accel;
 103 #else
 104     return 0;
 105 #endif
 106 }