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 libavcodec/ppc/check_altivec.c
  22  * Checks for AltiVec presence.
  23  */
  24
  25 #include "config.h"
  26
  27 #ifdef __APPLE__
  28 #undef _POSIX_C_SOURCE
  29 #include <sys/sysctl.h>
  30 #elif defined(__OpenBSD__)
  31 #include <sys/param.h>
  32 #include <sys/sysctl.h>
  33 #include <machine/cpu.h>
  34 #elif defined(__AMIGAOS4__)
  35 #include <exec/exec.h>
  36 #include <interfaces/exec.h>
  37 #include <proto/exec.h>
  38 #endif /* __APPLE__ */
  39
  40 /**
  41  * This function MAY rely on signal() or fork() in order to make sure AltiVec
  42  * is present.
  43  */
  44
  45 int has_altivec(void)
  46 {
  47 #ifdef __AMIGAOS4__
  48     ULONG result = 0;
  49     extern struct ExecIFace *IExec;
  50
  51     IExec->GetCPUInfoTags(GCIT_VectorUnit, &result, TAG_DONE);
  52     if (result == VECTORTYPE_ALTIVEC) return 1;
  53     return 0;
  54 #elif defined(__APPLE__) || defined(__OpenBSD__)
  55 #ifdef __OpenBSD__
  56     int sels[2] = {CTL_MACHDEP, CPU_ALTIVEC};
  57 #else
  58     int sels[2] = {CTL_HW, HW_VECTORUNIT};
  59 #endif
  60     int has_vu = 0;
  61     size_t len = sizeof(has_vu);
  62     int err;
  63
  64     err = sysctl(sels, 2, &has_vu, &len, NULL, 0);
  65
  66     if (err == 0) return has_vu != 0;
  67     return 0;
  68 #elif CONFIG_RUNTIME_CPUDETECT
  69     int proc_ver;
  70     // Support of mfspr PVR emulation added in Linux 2.6.17.
  71     __asm__ volatile("mfspr %0, 287" : "=r" (proc_ver));
  72     proc_ver >>= 16;
  73     if (proc_ver  & 0x8000 ||
  74         proc_ver == 0x000c ||
  75         proc_ver == 0x0039 || proc_ver == 0x003c ||
  76         proc_ver == 0x0044 || proc_ver == 0x0045 ||
  77         proc_ver == 0x0070)
  78         return 1;
  79     return 0;
  80 #else
  81     // Since we were compiled for AltiVec, just assume we have it
  82     // until someone comes up with a proper way (not involving signal hacks).
  83     return 1;
  84 #endif /* __AMIGAOS4__ */
  85 }
  86