ffmpeg/libavcodec/ppc/check_altivec.c
Luca Barbato 89523beea4 Sanitize altivec code so it can be built with runtime check properly
Originally committed as revision 10640 to svn://svn.ffmpeg.org/ffmpeg/trunk
2007-10-02 11:39:32 +00:00

96 lines
2.3 KiB
C

/*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file check_altivec.c
* Checks for AltiVec presence.
*/
#ifdef __APPLE__
#include <sys/sysctl.h>
#elif __AMIGAOS4__
#include <exec/exec.h>
#include <interfaces/exec.h>
#include <proto/exec.h>
#else
#include <signal.h>
#include <setjmp.h>
static sigjmp_buf jmpbuf;
static volatile sig_atomic_t canjump = 0;
static void sigill_handler (int sig)
{
if (!canjump) {
signal (sig, SIG_DFL);
raise (sig);
}
canjump = 0;
siglongjmp (jmpbuf, 1);
}
#endif /* __APPLE__ */
/**
* This function MAY rely on signal() or fork() in order to make sure altivec
* is present
*/
int has_altivec(void)
{
#ifdef __AMIGAOS4__
ULONG result = 0;
extern struct ExecIFace *IExec;
IExec->GetCPUInfoTags(GCIT_VectorUnit, &result, TAG_DONE);
if (result == VECTORTYPE_ALTIVEC) return 1;
return 0;
#elif __APPLE__
int sels[2] = {CTL_HW, HW_VECTORUNIT};
int has_vu = 0;
size_t len = sizeof(has_vu);
int err;
err = sysctl(sels, 2, &has_vu, &len, NULL, 0);
if (err == 0) return (has_vu != 0);
return 0;
#else
/* Do it the brute-force way, borrowed from the libmpeg2 library. */
{
signal (SIGILL, sigill_handler);
if (sigsetjmp (jmpbuf, 1)) {
signal (SIGILL, SIG_DFL);
} else {
canjump = 1;
asm volatile ("mtspr 256, %0\n\t"
"vand %%v0, %%v0, %%v0"
:
: "r" (-1));
signal (SIGILL, SIG_DFL);
return 1;
}
}
return 0;
#endif /* __AMIGAOS4__ */
}