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libavcodec
ppc
dsputil_ppc.c
Go to the documentation of this file.
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/*
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* Copyright (c) 2002 Brian Foley
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* Copyright (c) 2002 Dieter Shirley
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* Copyright (c) 2003-2004 Romain Dolbeau <romain@dolbeau.org>
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*
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* This file is part of Libav.
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*
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* Libav is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* Libav is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with Libav; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include <string.h>
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#include "
libavutil/cpu.h
"
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#include "
libavutil/mem.h
"
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#include "
libavcodec/dsputil.h
"
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#include "
dsputil_altivec.h
"
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/* ***** WARNING ***** WARNING ***** WARNING ***** */
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/*
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clear_blocks_dcbz32_ppc will not work properly on PowerPC processors with a
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cache line size not equal to 32 bytes.
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Fortunately all processor used by Apple up to at least the 7450 (aka second
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generation G4) use 32 bytes cache line.
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This is due to the use of the 'dcbz' instruction. It simply clear to zero a
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single cache line, so you need to know the cache line size to use it !
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It's absurd, but it's fast...
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update 24/06/2003 : Apple released yesterday the G5, with a PPC970. cache line
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size: 128 bytes. Oups.
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The semantic of dcbz was changed, it always clear 32 bytes. so the function
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below will work, but will be slow. So I fixed check_dcbz_effect to use dcbzl,
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which is defined to clear a cache line (as dcbz before). So we still can
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distinguish, and use dcbz (32 bytes) or dcbzl (one cache line) as required.
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see <http://developer.apple.com/technotes/tn/tn2087.html>
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and <http://developer.apple.com/technotes/tn/tn2086.html>
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*/
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static
void
clear_blocks_dcbz32_ppc
(
DCTELEM
*blocks)
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{
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register
int
misal = ((
unsigned
long)blocks & 0x00000010);
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register
int
i = 0;
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if
(misal) {
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((
unsigned
long
*)blocks)[0] = 0
L
;
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((
unsigned
long
*)blocks)[1] = 0
L
;
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((
unsigned
long
*)blocks)[2] = 0
L
;
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((
unsigned
long
*)blocks)[3] = 0
L
;
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i += 16;
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}
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for
( ; i <
sizeof
(
DCTELEM
)*6*64-31 ; i += 32) {
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__asm__
volatile
(
"dcbz %0,%1"
: :
"b"
(blocks),
"r"
(i) :
"memory"
);
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}
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if
(misal) {
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((
unsigned
long
*)blocks)[188] = 0
L
;
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((
unsigned
long
*)blocks)[189] = 0
L
;
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((
unsigned
long
*)blocks)[190] = 0
L
;
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((
unsigned
long
*)blocks)[191] = 0
L
;
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i += 16;
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}
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}
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/* same as above, when dcbzl clear a whole 128B cache line
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i.e. the PPC970 aka G5 */
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#if HAVE_DCBZL
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static
void
clear_blocks_dcbz128_ppc
(
DCTELEM
*blocks)
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{
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register
int
misal = ((
unsigned
long)blocks & 0x0000007f);
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register
int
i = 0;
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if
(misal) {
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// we could probably also optimize this case,
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// but there's not much point as the machines
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// aren't available yet (2003-06-26)
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memset(blocks, 0,
sizeof
(
DCTELEM
)*6*64);
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}
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else
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for
( ; i <
sizeof
(
DCTELEM
)*6*64 ; i += 128) {
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__asm__
volatile
(
"dcbzl %0,%1"
: :
"b"
(blocks),
"r"
(i) :
"memory"
);
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}
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}
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#else
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static
void
clear_blocks_dcbz128_ppc
(
DCTELEM
*blocks)
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{
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memset(blocks, 0,
sizeof
(
DCTELEM
)*6*64);
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}
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#endif
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#if HAVE_DCBZL
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/* check dcbz report how many bytes are set to 0 by dcbz */
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/* update 24/06/2003 : replace dcbz by dcbzl to get
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the intended effect (Apple "fixed" dcbz)
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unfortunately this cannot be used unless the assembler
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knows about dcbzl ... */
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static
long
check_dcbzl_effect
(
void
)
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{
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register
char
*fakedata =
av_malloc
(1024);
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register
char
*fakedata_middle;
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register
long
zero
= 0;
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register
long
i = 0;
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long
count = 0;
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if
(!fakedata) {
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return
0
L
;
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}
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fakedata_middle = (fakedata + 512);
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memset(fakedata, 0xFF, 1024);
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/* below the constraint "b" seems to mean "Address base register"
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in gcc-3.3 / RS/6000 speaks. seems to avoid using r0, so.... */
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__asm__
volatile
(
"dcbzl %0, %1"
: :
"b"
(fakedata_middle),
"r"
(zero));
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for
(i = 0; i < 1024 ; i ++) {
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if
(fakedata[i] == (
char
)0)
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count++;
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}
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av_free
(fakedata);
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return
count;
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}
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#else
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static
long
check_dcbzl_effect
(
void
)
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{
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return
0;
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}
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#endif
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void
ff_dsputil_init_ppc
(
DSPContext
* c,
AVCodecContext
*avctx)
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{
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const
int
high_bit_depth = avctx->
bits_per_raw_sample
> 8;
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// Common optimizations whether AltiVec is available or not
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if
(!high_bit_depth) {
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switch
(
check_dcbzl_effect
()) {
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case
32:
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c->
clear_blocks
=
clear_blocks_dcbz32_ppc
;
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break
;
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case
128:
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c->
clear_blocks
=
clear_blocks_dcbz128_ppc
;
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break
;
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default
:
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break
;
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}
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}
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#if HAVE_ALTIVEC
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if
(
CONFIG_H264_DECODER
)
ff_dsputil_h264_init_ppc
(c, avctx);
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if
(
av_get_cpu_flags
() &
AV_CPU_FLAG_ALTIVEC
) {
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ff_dsputil_init_altivec
(c, avctx);
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ff_float_init_altivec
(c, avctx);
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ff_int_init_altivec
(c, avctx);
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c->
gmc1
=
ff_gmc1_altivec
;
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#if CONFIG_ENCODERS
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if
(avctx->
bits_per_raw_sample
<= 8 &&
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(avctx->
dct_algo
==
FF_DCT_AUTO
||
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avctx->
dct_algo
==
FF_DCT_ALTIVEC
)) {
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c->
fdct
=
ff_fdct_altivec
;
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}
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#endif //CONFIG_ENCODERS
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if
(avctx->
bits_per_raw_sample
<= 8) {
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if
((avctx->
idct_algo
==
FF_IDCT_AUTO
) ||
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(avctx->
idct_algo
==
FF_IDCT_ALTIVEC
)) {
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c->
idct_put
=
ff_idct_put_altivec
;
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c->
idct_add
=
ff_idct_add_altivec
;
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c->
idct_permutation_type
=
FF_TRANSPOSE_IDCT_PERM
;
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}
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}
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}
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#endif
/* HAVE_ALTIVEC */
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}