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/*
* Copyright (c) 2002 Brian Foley
* Copyright (c) 2002 Dieter Shirley
* Copyright (c) 2003-2004 Romain Dolbeau <romain@dolbeau.org>
*
* 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
*/
#include "config.h"
#include <string.h>
#include "libavutil/attributes.h"
#include "libavutil/cpu.h"
#include "libavutil/mem.h"
#include "libavutil/ppc/cpu.h"
#include "libavutil/ppc/util_altivec.h"
#include "libavcodec/blockdsp.h"
/* ***** WARNING ***** WARNING ***** WARNING ***** */
/*
* clear_blocks_dcbz32_ppc will not work properly on PowerPC processors with
* a cache line size not equal to 32 bytes. Fortunately all processors used
* by Apple up to at least the 7450 (AKA second generation G4) use 32-byte
* cache lines. This is due to the use of the 'dcbz' instruction. It simply
* clears a single cache line to zero, so you need to know the cache line
* size to use it! It's absurd, but it's fast...
*
* update 24/06/2003: Apple released the G5 yesterday, with a PPC970.
* cache line size: 128 bytes. Oups.
* The semantics of dcbz was changed, it always clears 32 bytes. So the function
* below will work, but will be slow. So I fixed check_dcbz_effect to use dcbzl,
* which is defined to clear a cache line (as dcbz before). So we can still
* distinguish, and use dcbz (32 bytes) or dcbzl (one cache line) as required.
*
* see <http://developer.apple.com/technotes/tn/tn2087.html>
* and <http://developer.apple.com/technotes/tn/tn2086.html>
*/
static void clear_blocks_dcbz32_ppc(int16_t *blocks)
{
register int misal = (unsigned long) blocks & 0x00000010, i = 0;
if (misal) {
((unsigned long *) blocks)[0] = 0L;
((unsigned long *) blocks)[1] = 0L;
((unsigned long *) blocks)[2] = 0L;
((unsigned long *) blocks)[3] = 0L;
i += 16;
}
for (; i < sizeof(int16_t) * 6 * 64 - 31; i += 32)
__asm__ volatile ("dcbz %0,%1" :: "b" (blocks), "r" (i) : "memory");
if (misal) {
((unsigned long *) blocks)[188] = 0L;
((unsigned long *) blocks)[189] = 0L;
((unsigned long *) blocks)[190] = 0L;
((unsigned long *) blocks)[191] = 0L;
i += 16;
}
}
/* Same as above, when dcbzl clears a whole 128 bytes cache line
* i.e. the PPC970 AKA G5. */
static void clear_blocks_dcbz128_ppc(int16_t *blocks)
{
#if HAVE_DCBZL
register int misal = (unsigned long) blocks & 0x0000007f, i = 0;
if (misal) {
/* We could probably also optimize this case,
* but there's not much point as the machines
* aren't available yet (2003-06-26). */
memset(blocks, 0, sizeof(int16_t) * 6 * 64);
} else {
for (; i < sizeof(int16_t) * 6 * 64; i += 128)
__asm__ volatile ("dcbzl %0,%1" :: "b" (blocks), "r" (i) : "memory");
}
#else
memset(blocks, 0, sizeof(int16_t) * 6 * 64);
#endif
}
/* Check dcbz report how many bytes are set to 0 by dcbz. */
/* update 24/06/2003: Replace dcbz by dcbzl to get the intended effect
* (Apple "fixed" dcbz). Unfortunately this cannot be used unless the
* assembler knows about dcbzl ... */
static long check_dcbzl_effect(void)
{
long count = 0;
#if HAVE_DCBZL
register char *fakedata = av_malloc(1024);
register char *fakedata_middle;
register long zero = 0, i = 0;
if (!fakedata)
return 0L;
fakedata_middle = fakedata + 512;
memset(fakedata, 0xFF, 1024);
/* Below the constraint "b" seems to mean "address base register"
* in gcc-3.3 / RS/6000 speaks. Seems to avoid using r0, so.... */
__asm__ volatile ("dcbzl %0, %1" :: "b" (fakedata_middle), "r" (zero));
for (i = 0; i < 1024; i++)
if (fakedata[i] == (char) 0)
count++;
av_free(fakedata);
#endif
return count;
}
#if HAVE_ALTIVEC
static void clear_block_altivec(int16_t *block)
{
LOAD_ZERO;
vec_st(zero_s16v, 0, block);
vec_st(zero_s16v, 16, block);
vec_st(zero_s16v, 32, block);
vec_st(zero_s16v, 48, block);
vec_st(zero_s16v, 64, block);
vec_st(zero_s16v, 80, block);
vec_st(zero_s16v, 96, block);
vec_st(zero_s16v, 112, block);
}
#endif /* HAVE_ALTIVEC */
av_cold void ff_blockdsp_init_ppc(BlockDSPContext *c)
{
// common optimizations whether AltiVec is available or not
switch (check_dcbzl_effect()) {
case 32:
c->clear_blocks = clear_blocks_dcbz32_ppc;
break;
case 128:
c->clear_blocks = clear_blocks_dcbz128_ppc;
break;
default:
break;
}
#if HAVE_ALTIVEC
if (!PPC_ALTIVEC(av_get_cpu_flags()))
return;
c->clear_block = clear_block_altivec;
#endif /* HAVE_ALTIVEC */
}
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