ffmpeg/libavutil/x86/cpu.c

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/*
* CPU detection code, extracted from mmx.h
* (c)1997-99 by H. Dietz and R. Fisher
* Converted to C and improved by Fabrice Bellard.
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <stdlib.h>
#include <string.h>
#include "libavutil/x86_cpu.h"
#include "libavutil/cpu.h"
/* ebx saving is necessary for PIC. gcc seems unable to see it alone */
#define cpuid(index,eax,ebx,ecx,edx)\
__asm__ volatile\
("mov %%"REG_b", %%"REG_S"\n\t"\
"cpuid\n\t"\
"xchg %%"REG_b", %%"REG_S\
: "=a" (eax), "=S" (ebx),\
"=c" (ecx), "=d" (edx)\
: "0" (index));
/* Function to test if multimedia instructions are supported... */
int ff_get_cpu_flags_x86(void)
{
int rval = 0;
int eax, ebx, ecx, edx;
int max_std_level, max_ext_level, std_caps=0, ext_caps=0;
int family=0, model=0;
union { int i[3]; char c[12]; } vendor;
#if ARCH_X86_32
x86_reg a, c;
__asm__ volatile (
/* See if CPUID instruction is supported ... */
/* ... Get copies of EFLAGS into eax and ecx */
"pushfl\n\t"
"pop %0\n\t"
"mov %0, %1\n\t"
/* ... Toggle the ID bit in one copy and store */
/* to the EFLAGS reg */
"xor $0x200000, %0\n\t"
"push %0\n\t"
"popfl\n\t"
/* ... Get the (hopefully modified) EFLAGS */
"pushfl\n\t"
"pop %0\n\t"
: "=a" (a), "=c" (c)
:
: "cc"
);
if (a == c)
return 0; /* CPUID not supported */
#endif
cpuid(0, max_std_level, vendor.i[0], vendor.i[2], vendor.i[1]);
if(max_std_level >= 1){
cpuid(1, eax, ebx, ecx, std_caps);
family = ((eax>>8)&0xf) + ((eax>>20)&0xff);
model = ((eax>>4)&0xf) + ((eax>>12)&0xf0);
if (std_caps & (1<<23))
rval |= AV_CPU_FLAG_MMX;
if (std_caps & (1<<25))
rval |= AV_CPU_FLAG_MMX2
#if HAVE_SSE
| AV_CPU_FLAG_SSE;
if (std_caps & (1<<26))
rval |= AV_CPU_FLAG_SSE2;
if (ecx & 1)
rval |= AV_CPU_FLAG_SSE3;
if (ecx & 0x00000200 )
rval |= AV_CPU_FLAG_SSSE3;
if (ecx & 0x00080000 )
rval |= AV_CPU_FLAG_SSE4;
if (ecx & 0x00100000 )
rval |= AV_CPU_FLAG_SSE42;
#endif
;
}
cpuid(0x80000000, max_ext_level, ebx, ecx, edx);
if(max_ext_level >= 0x80000001){
cpuid(0x80000001, eax, ebx, ecx, ext_caps);
if (ext_caps & (1<<31))
rval |= AV_CPU_FLAG_3DNOW;
if (ext_caps & (1<<30))
rval |= AV_CPU_FLAG_3DNOWEXT;
if (ext_caps & (1<<23))
rval |= AV_CPU_FLAG_MMX;
if (ext_caps & (1<<22))
rval |= AV_CPU_FLAG_MMX2;
}
if (!strncmp(vendor.c, "GenuineIntel", 12) &&
family == 6 && (model == 9 || model == 13 || model == 14)) {
/* 6/9 (pentium-m "banias"), 6/13 (pentium-m "dothan"), and 6/14 (core1 "yonah")
* theoretically support sse2, but it's usually slower than mmx,
* so let's just pretend they don't. */
if (rval & AV_CPU_FLAG_SSE2) rval ^= AV_CPU_FLAG_SSE2SLOW|AV_CPU_FLAG_SSE2;
if (rval & AV_CPU_FLAG_SSE3) rval ^= AV_CPU_FLAG_SSE3SLOW|AV_CPU_FLAG_SSE3;
}
return rval;
}