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