Suppressing external gas stuff to improve portability to Win32
[libav.git] / libavcodec / i386 / cputest.c
1 /* Cpu detection code, extracted from mmx.h ((c)1997-99 by H. Dietz
2 and R. Fisher). Converted to C and improved by Gerard Lantau */
3
4 #include <stdlib.h>
5 #include "../dsputil.h"
6
7 /* ebx saving is necessary for PIC. gcc seems unable to see it alone */
8 #define cpuid(index,eax,ebx,ecx,edx)\
9 asm ("movl %%ebx, %%esi\n\t"\
10 "cpuid\n\t"\
11 "xchgl %%ebx, %%esi"\
12 : "=a" (eax), "=S" (ebx),\
13 "=c" (ecx), "=d" (edx)\
14 : "0" (index)\
15 : "cc")\
16
17 /* Function to test if multimedia instructions are supported... */
18 int mm_support(void)
19 {
20 int rval;
21 int eax, ebx, ecx, edx;
22
23 __asm__ __volatile__ (
24 /* See if CPUID instruction is supported ... */
25 /* ... Get copies of EFLAGS into eax and ecx */
26 "pushf\n\t"
27 "popl %0\n\t"
28 "movl %0, %1\n\t"
29
30 /* ... Toggle the ID bit in one copy and store */
31 /* to the EFLAGS reg */
32 "xorl $0x200000, %0\n\t"
33 "push %0\n\t"
34 "popf\n\t"
35
36 /* ... Get the (hopefully modified) EFLAGS */
37 "pushf\n\t"
38 "popl %0\n\t"
39 : "=a" (eax), "=c" (ecx)
40 :
41 : "cc"
42 );
43
44 if (eax == ecx)
45 return 0; /* CPUID not supported */
46
47 cpuid(0, eax, ebx, ecx, edx);
48
49 if (ebx == 0x756e6547 &&
50 edx == 0x49656e69 &&
51 ecx == 0x6c65746e) {
52
53 /* intel */
54 inteltest:
55 cpuid(1, eax, ebx, ecx, edx);
56 if ((edx & 0x00800000) == 0)
57 return 0;
58 rval = MM_MMX;
59 if (edx & 0x02000000)
60 rval |= MM_MMXEXT | MM_SSE;
61 if (edx & 0x04000000)
62 rval |= MM_SSE2;
63 return rval;
64 } else if (ebx == 0x68747541 &&
65 edx == 0x69746e65 &&
66 ecx == 0x444d4163) {
67 /* AMD */
68 cpuid(0x80000000, eax, ebx, ecx, edx);
69 if ((unsigned)eax < 0x80000001)
70 goto inteltest;
71 cpuid(0x80000001, eax, ebx, ecx, edx);
72 if ((edx & 0x00800000) == 0)
73 return 0;
74 rval = MM_MMX;
75 if (edx & 0x80000000)
76 rval |= MM_3DNOW;
77 if (edx & 0x00400000)
78 rval |= MM_MMXEXT;
79 return rval;
80 } else if (ebx == 0x69727943 &&
81 edx == 0x736e4978 &&
82 ecx == 0x64616574) {
83 /* Cyrix Section */
84 /* See if extended CPUID level 80000001 is supported */
85 /* The value of CPUID/80000001 for the 6x86MX is undefined
86 according to the Cyrix CPU Detection Guide (Preliminary
87 Rev. 1.01 table 1), so we'll check the value of eax for
88 CPUID/0 to see if standard CPUID level 2 is supported.
89 According to the table, the only CPU which supports level
90 2 is also the only one which supports extended CPUID levels.
91 */
92 if (eax != 2)
93 goto inteltest;
94 cpuid(0x80000001, eax, ebx, ecx, edx);
95 if ((eax & 0x00800000) == 0)
96 return 0;
97 rval = MM_MMX;
98 if (eax & 0x01000000)
99 rval |= MM_MMXEXT;
100 return rval;
101 } else {
102 return 0;
103 }
104 }