via c3 detection patch by (Francisco Javier Cabello Torres <fjcabello at visual-tools...
[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 Fabrice Bellard */
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 __volatile\
10 ("movl %%ebx, %%esi\n\t"\
11 "cpuid\n\t"\
12 "xchgl %%ebx, %%esi"\
13 : "=a" (eax), "=S" (ebx),\
14 "=c" (ecx), "=d" (edx)\
15 : "0" (index));
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 == 0x746e6543 &&
81 edx == 0x48727561 &&
82 ecx == 0x736c7561) { /* "CentaurHauls" */
83 /* VIA C3 */
84 cpuid(0x80000000, eax, ebx, ecx, edx);
85 if ((unsigned)eax < 0x80000001)
86 goto inteltest;
87 cpuid(0x80000001, eax, ebx, ecx, edx);
88 rval = 0;
89 if( edx & ( 1 << 31) )
90 rval |= MM_3DNOW;
91 if( edx & ( 1 << 23) )
92 rval |= MM_MMX;
93 if( edx & ( 1 << 24) )
94 rval |= MM_MMXEXT;
95 } else if (ebx == 0x69727943 &&
96 edx == 0x736e4978 &&
97 ecx == 0x64616574) {
98 /* Cyrix Section */
99 /* See if extended CPUID level 80000001 is supported */
100 /* The value of CPUID/80000001 for the 6x86MX is undefined
101 according to the Cyrix CPU Detection Guide (Preliminary
102 Rev. 1.01 table 1), so we'll check the value of eax for
103 CPUID/0 to see if standard CPUID level 2 is supported.
104 According to the table, the only CPU which supports level
105 2 is also the only one which supports extended CPUID levels.
106 */
107 if (eax != 2)
108 goto inteltest;
109 cpuid(0x80000001, eax, ebx, ecx, edx);
110 if ((eax & 0x00800000) == 0)
111 return 0;
112 rval = MM_MMX;
113 if (eax & 0x01000000)
114 rval |= MM_MMXEXT;
115 return rval;
116 } else {
117 return 0;
118 }
119 }
120
121 #ifdef __TEST__
122 int main ( void )
123 {
124 int mm_flags;
125 mm_flags = mm_support();
126 printf("mm_support = 0x%08u\n",mm_flags);
127 return 0;
128 }
129 #endif