mirror of
https://github.com/FFmpeg/FFmpeg.git
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115 lines
3.5 KiB
C
115 lines
3.5 KiB
C
/* 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 Gerard Lantau */
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#include <stdlib.h>
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#include "../dsputil.h"
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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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("movl %%ebx, %%esi\n\t"\
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"cpuid\n\t"\
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"xchgl %%ebx, %%esi"\
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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;
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int eax, ebx, ecx, edx;
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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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"popl %0\n\t"
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"movl %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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"xorl $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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"popl %0\n\t"
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: "=a" (eax), "=c" (ecx)
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:
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: "cc"
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);
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if (eax == ecx)
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return 0; /* CPUID not supported */
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cpuid(0, eax, ebx, ecx, edx);
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if (ebx == 0x756e6547 &&
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edx == 0x49656e69 &&
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ecx == 0x6c65746e) {
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/* intel */
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inteltest:
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cpuid(1, eax, ebx, ecx, edx);
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if ((edx & 0x00800000) == 0)
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return 0;
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rval = MM_MMX;
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if (edx & 0x02000000)
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rval |= MM_MMXEXT | MM_SSE;
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if (edx & 0x04000000)
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rval |= MM_SSE2;
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return rval;
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} else if (ebx == 0x68747541 &&
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edx == 0x69746e65 &&
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ecx == 0x444d4163) {
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/* AMD */
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cpuid(0x80000000, eax, ebx, ecx, edx);
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if ((unsigned)eax < 0x80000001)
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goto inteltest;
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cpuid(0x80000001, eax, ebx, ecx, edx);
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if ((edx & 0x00800000) == 0)
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return 0;
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rval = MM_MMX;
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if (edx & 0x80000000)
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rval |= MM_3DNOW;
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if (edx & 0x00400000)
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rval |= MM_MMXEXT;
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return rval;
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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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goto inteltest;
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cpuid(0x80000001, eax, ebx, ecx, edx);
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if ((eax & 0x00800000) == 0)
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return 0;
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rval = MM_MMX;
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if (eax & 0x01000000)
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rval |= MM_MMXEXT;
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return rval;
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} else {
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return 0;
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}
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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%08u\n",mm_flags);
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return 0;
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}
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#endif
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