[FFmpeg-devel] [PATCH] Make ff_inverse stay with libavutil, and optional copy it to libavcodec.
Diego Elio 'Flameeyes' Pettenò
flameeyes
Tue Jul 20 18:16:51 CEST 2010
The ff_inverse table is used by FASTDIV macro, defined in libavutil, but up
to now the table was defined only in libavcodec.
After this change, the main copy of ff_inverse is part of libavutil (just
like FASTDIV), but if CONFIG_SMALL is unset, then a different copy is made
available to libavcodec, to avoid the performance penalty of using an
external look up table.
Dynamic linking works, because the libraries are linked with -Bsymbolic, so
the local copy of the symbol has priority over the external; static linking
works because the table is on a standalone object file in both libraries,
so the linker is able to discard one of the two.
Tested on Linux/x86-64 and Mac OS X/x86-64.
---
libavcodec/Makefile | 2 +
libavcodec/dsputil.c | 38 -------------------------------
libavutil/Makefile | 1 +
libavutil/inverse.c | 60 ++++++++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 63 insertions(+), 38 deletions(-)
create mode 100644 libavutil/inverse.c
diff --git a/libavcodec/Makefile b/libavcodec/Makefile
index 965948c..fab5211 100644
--- a/libavcodec/Makefile
+++ b/libavcodec/Makefile
@@ -609,6 +609,8 @@ OBJS-$(HAVE_W32THREADS) += w32thread.o
OBJS-$(CONFIG_MLIB) += mlib/dsputil_mlib.o \
+OBJS-$(!CONFIG_SMALL) += ../libavutil/inverse.o
+
-include $(SUBDIR)$(ARCH)/Makefile
SKIPHEADERS = %_tablegen.h
diff --git a/libavcodec/dsputil.c b/libavcodec/dsputil.c
index 44fcf59..a6424bb 100644
--- a/libavcodec/dsputil.c
+++ b/libavcodec/dsputil.c
@@ -97,44 +97,6 @@ const uint8_t ff_alternate_vertical_scan[64] = {
38, 46, 54, 62, 39, 47, 55, 63,
};
-/* a*inverse[b]>>32 == a/b for all 0<=a<=16909558 && 2<=b<=256
- * for a>16909558, is an overestimate by less than 1 part in 1<<24 */
-const uint32_t ff_inverse[257]={
- 0, 4294967295U,2147483648U,1431655766, 1073741824, 858993460, 715827883, 613566757,
- 536870912, 477218589, 429496730, 390451573, 357913942, 330382100, 306783379, 286331154,
- 268435456, 252645136, 238609295, 226050911, 214748365, 204522253, 195225787, 186737709,
- 178956971, 171798692, 165191050, 159072863, 153391690, 148102321, 143165577, 138547333,
- 134217728, 130150525, 126322568, 122713352, 119304648, 116080198, 113025456, 110127367,
- 107374183, 104755300, 102261127, 99882961, 97612894, 95443718, 93368855, 91382283,
- 89478486, 87652394, 85899346, 84215046, 82595525, 81037119, 79536432, 78090315,
- 76695845, 75350304, 74051161, 72796056, 71582789, 70409300, 69273667, 68174085,
- 67108864, 66076420, 65075263, 64103990, 63161284, 62245903, 61356676, 60492498,
- 59652324, 58835169, 58040099, 57266231, 56512728, 55778797, 55063684, 54366675,
- 53687092, 53024288, 52377650, 51746594, 51130564, 50529028, 49941481, 49367441,
- 48806447, 48258060, 47721859, 47197443, 46684428, 46182445, 45691142, 45210183,
- 44739243, 44278014, 43826197, 43383509, 42949673, 42524429, 42107523, 41698712,
- 41297763, 40904451, 40518560, 40139882, 39768216, 39403370, 39045158, 38693400,
- 38347923, 38008561, 37675152, 37347542, 37025581, 36709123, 36398028, 36092163,
- 35791395, 35495598, 35204650, 34918434, 34636834, 34359739, 34087043, 33818641,
- 33554432, 33294321, 33038210, 32786010, 32537632, 32292988, 32051995, 31814573,
- 31580642, 31350127, 31122952, 30899046, 30678338, 30460761, 30246249, 30034737,
- 29826162, 29620465, 29417585, 29217465, 29020050, 28825284, 28633116, 28443493,
- 28256364, 28071682, 27889399, 27709467, 27531842, 27356480, 27183338, 27012373,
- 26843546, 26676816, 26512144, 26349493, 26188825, 26030105, 25873297, 25718368,
- 25565282, 25414008, 25264514, 25116768, 24970741, 24826401, 24683721, 24542671,
- 24403224, 24265352, 24129030, 23994231, 23860930, 23729102, 23598722, 23469767,
- 23342214, 23216040, 23091223, 22967740, 22845571, 22724695, 22605092, 22486740,
- 22369622, 22253717, 22139007, 22025474, 21913099, 21801865, 21691755, 21582751,
- 21474837, 21367997, 21262215, 21157475, 21053762, 20951060, 20849356, 20748635,
- 20648882, 20550083, 20452226, 20355296, 20259280, 20164166, 20069941, 19976593,
- 19884108, 19792477, 19701685, 19611723, 19522579, 19434242, 19346700, 19259944,
- 19173962, 19088744, 19004281, 18920561, 18837576, 18755316, 18673771, 18592933,
- 18512791, 18433337, 18354562, 18276457, 18199014, 18122225, 18046082, 17970575,
- 17895698, 17821442, 17747799, 17674763, 17602325, 17530479, 17459217, 17388532,
- 17318417, 17248865, 17179870, 17111424, 17043522, 16976156, 16909321, 16843010,
- 16777216
-};
-
/* Input permutation for the simple_idct_mmx */
static const uint8_t simple_mmx_permutation[64]={
0x00, 0x08, 0x04, 0x09, 0x01, 0x0C, 0x05, 0x0D,
diff --git a/libavutil/Makefile b/libavutil/Makefile
index 9238808..0c25ce1 100644
--- a/libavutil/Makefile
+++ b/libavutil/Makefile
@@ -39,6 +39,7 @@ OBJS = adler32.o \
eval.o \
fifo.o \
intfloat_readwrite.o \
+ inverse.o \
lfg.o \
lls.o \
log.o \
diff --git a/libavutil/inverse.c b/libavutil/inverse.c
new file mode 100644
index 0000000..74df1c2
--- /dev/null
+++ b/libavutil/inverse.c
@@ -0,0 +1,60 @@
+/*
+ * Inverse table
+ * Copyright (c) 2002-2004 Michael Niedermayer <michaelni at gmx.at>
+ *
+ * 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 "libavutil/intmath.h"
+
+/* a*inverse[b]>>32 == a/b for all 0<=a<=16909558 && 2<=b<=256
+ * for a>16909558, is an overestimate by less than 1 part in 1<<24 */
+const uint32_t ff_inverse[257]={
+ 0, 4294967295U,2147483648U,1431655766, 1073741824, 858993460, 715827883, 613566757,
+ 536870912, 477218589, 429496730, 390451573, 357913942, 330382100, 306783379, 286331154,
+ 268435456, 252645136, 238609295, 226050911, 214748365, 204522253, 195225787, 186737709,
+ 178956971, 171798692, 165191050, 159072863, 153391690, 148102321, 143165577, 138547333,
+ 134217728, 130150525, 126322568, 122713352, 119304648, 116080198, 113025456, 110127367,
+ 107374183, 104755300, 102261127, 99882961, 97612894, 95443718, 93368855, 91382283,
+ 89478486, 87652394, 85899346, 84215046, 82595525, 81037119, 79536432, 78090315,
+ 76695845, 75350304, 74051161, 72796056, 71582789, 70409300, 69273667, 68174085,
+ 67108864, 66076420, 65075263, 64103990, 63161284, 62245903, 61356676, 60492498,
+ 59652324, 58835169, 58040099, 57266231, 56512728, 55778797, 55063684, 54366675,
+ 53687092, 53024288, 52377650, 51746594, 51130564, 50529028, 49941481, 49367441,
+ 48806447, 48258060, 47721859, 47197443, 46684428, 46182445, 45691142, 45210183,
+ 44739243, 44278014, 43826197, 43383509, 42949673, 42524429, 42107523, 41698712,
+ 41297763, 40904451, 40518560, 40139882, 39768216, 39403370, 39045158, 38693400,
+ 38347923, 38008561, 37675152, 37347542, 37025581, 36709123, 36398028, 36092163,
+ 35791395, 35495598, 35204650, 34918434, 34636834, 34359739, 34087043, 33818641,
+ 33554432, 33294321, 33038210, 32786010, 32537632, 32292988, 32051995, 31814573,
+ 31580642, 31350127, 31122952, 30899046, 30678338, 30460761, 30246249, 30034737,
+ 29826162, 29620465, 29417585, 29217465, 29020050, 28825284, 28633116, 28443493,
+ 28256364, 28071682, 27889399, 27709467, 27531842, 27356480, 27183338, 27012373,
+ 26843546, 26676816, 26512144, 26349493, 26188825, 26030105, 25873297, 25718368,
+ 25565282, 25414008, 25264514, 25116768, 24970741, 24826401, 24683721, 24542671,
+ 24403224, 24265352, 24129030, 23994231, 23860930, 23729102, 23598722, 23469767,
+ 23342214, 23216040, 23091223, 22967740, 22845571, 22724695, 22605092, 22486740,
+ 22369622, 22253717, 22139007, 22025474, 21913099, 21801865, 21691755, 21582751,
+ 21474837, 21367997, 21262215, 21157475, 21053762, 20951060, 20849356, 20748635,
+ 20648882, 20550083, 20452226, 20355296, 20259280, 20164166, 20069941, 19976593,
+ 19884108, 19792477, 19701685, 19611723, 19522579, 19434242, 19346700, 19259944,
+ 19173962, 19088744, 19004281, 18920561, 18837576, 18755316, 18673771, 18592933,
+ 18512791, 18433337, 18354562, 18276457, 18199014, 18122225, 18046082, 17970575,
+ 17895698, 17821442, 17747799, 17674763, 17602325, 17530479, 17459217, 17388532,
+ 17318417, 17248865, 17179870, 17111424, 17043522, 16976156, 16909321, 16843010,
+ 16777216
+};
--
1.7.1.1
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