Add mfspr-based AltiVec detection code.
[libav.git] / libavcodec / ppc / check_altivec.c
1 /*
2 * This file is part of FFmpeg.
3 *
4 * FFmpeg is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Lesser General Public
6 * License as published by the Free Software Foundation; either
7 * version 2.1 of the License, or (at your option) any later version.
8 *
9 * FFmpeg is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * Lesser General Public License for more details.
13 *
14 * You should have received a copy of the GNU Lesser General Public
15 * License along with FFmpeg; if not, write to the Free Software
16 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
17 */
18
19
20 /**
21 * @file check_altivec.c
22 * Checks for AltiVec presence.
23 */
24
25 #ifdef __APPLE__
26 #include <sys/sysctl.h>
27 #elif __AMIGAOS4__
28 #include <exec/exec.h>
29 #include <interfaces/exec.h>
30 #include <proto/exec.h>
31 #endif /* __APPLE__ */
32
33 /**
34 * This function MAY rely on signal() or fork() in order to make sure altivec
35 * is present
36 */
37
38 int has_altivec(void)
39 {
40 #ifdef __AMIGAOS4__
41 ULONG result = 0;
42 extern struct ExecIFace *IExec;
43
44 IExec->GetCPUInfoTags(GCIT_VectorUnit, &result, TAG_DONE);
45 if (result == VECTORTYPE_ALTIVEC) return 1;
46 return 0;
47 #elif __APPLE__
48 int sels[2] = {CTL_HW, HW_VECTORUNIT};
49 int has_vu = 0;
50 size_t len = sizeof(has_vu);
51 int err;
52
53 err = sysctl(sels, 2, &has_vu, &len, NULL, 0);
54
55 if (err == 0) return (has_vu != 0);
56 return 0;
57 #elif defined(RUNTIME_CPUDETECT)
58 int proc_ver;
59 // support of mfspr PVR emulation added in Linux 2.6.17
60 asm volatile("mfspr %0, 287" : "=r" (proc_ver));
61 proc_ver >>= 16;
62 if (proc_ver & 0x8000 ||
63 proc_ver == 0x000c ||
64 proc_ver == 0x0039 || proc_ver == 0x003c ||
65 proc_ver == 0x0044 || proc_ver == 0x0045 ||
66 proc_ver == 0x0070)
67 return 1;
68 return 0;
69 #else
70 // since we were compiled for altivec, just assume we have it
71 // until someone comes up with a proper way (not involving signal hacks).
72 return 1;
73 #endif /* __AMIGAOS4__ */
74 }
75