hvirtual/mpeg2enc/cpu_accel.c

Go to the documentation of this file.

/*
 * cpu_accel.c
 * Copyright (C) 1999-2000 Aaron Holtzman <aholtzma@ess.engr.uvic.ca>
 *
 * This file is part of mpeg2dec, a free MPEG-2 video stream decoder.
 *
 * mpeg2dec is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * mpeg2dec is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include <stdio.h>
#include <inttypes.h>

#include "cpu_accel.h"

#ifdef X86_CPU
static int x86_accel (void)
{
    int eax, ebx, ecx, edx;
    int AMD;
    int caps;

#define cpuid(op,eax,ebx,ecx,edx)       \
    asm ("cpuid"                        \
         : "=a" (eax),                  \
           "=b" (ebx),                  \
           "=c" (ecx),                  \
           "=d" (edx)                   \
         : "a" (op)                     \
         : "cc")

    asm ("pushfl\n\t"
         "popl %0\n\t"
         "movl %0,%1\n\t"
         "xorl $0x200000,%0\n\t"
         "pushl %0\n\t"
         "popfl\n\t"
         "pushfl\n\t"
         "popl %0"
         : "=a" (eax),
           "=b" (ebx)
         :
         : "cc");

    if (eax == ebx)             // no cpuid
        return 0;

    cpuid (0x00000000, eax, ebx, ecx, edx);
    if (!eax)                   // vendor string only
        return 0;

    AMD = (ebx == 0x68747541) && (ecx == 0x444d4163) && (edx == 0x69746e65);

    cpuid (0x00000001, eax, ebx, ecx, edx);
    if (! (edx & 0x00800000))   // no MMX
        return 0;

    caps = ACCEL_X86_MMX;
    if (edx & 0x02000000)       // SSE - identical to AMD MMX extensions
        caps = ACCEL_X86_MMX | ACCEL_X86_MMXEXT;

    cpuid (0x80000000, eax, ebx, ecx, edx);
    if (eax < 0x80000001)       // no extended capabilities
        return caps;

    cpuid (0x80000001, eax, ebx, ecx, edx);

    if (edx & 0x80000000)
        caps |= ACCEL_X86_3DNOW;

    if (AMD && (edx & 0x00400000))      // AMD MMX extensions
        {
                caps |= ACCEL_X86_MMXEXT;
        }

    return caps;
}
#endif

int cpu_accel (void)
{
#ifdef X86_CPU
    static int got_accel = 0;
    static int accel;

    if (!got_accel) {
        got_accel = 1;
        accel = x86_accel ();
    }

    return accel;
#else
    return 0;
#endif
}

---