From 14e9ffc1e41424a530c83310611979c0d246417b Mon Sep 17 00:00:00 2001
From: Roland Scheidegger <rscheidegger_lists@hispeed.ch>
Date: Fri, 27 Apr 2012 22:19:38 +0200
Subject: [PATCH] h264: use one table instead of several for cabac functions

The reason is this is easier for PIC code (in particular on darwin...).
Keep the old names as pointers (static in cabac_functions.h so gcc
knows these are just immediate offsets) so the c code can nicely stay the same
(alternatively could use offsets directly in the functions needing the
tables). This should produce the same code as before with non-pic and better
code (confirmed) with pic.

The assembly uses the new table but still won't work for PIC case.

Signed-off-by: Ronald S. Bultje <rsbultje@gmail.com>
---
 libavcodec/cabac.c           | 54 +++++++++++++++++++++---------------
 libavcodec/cabac.h           |  5 ++++
 libavcodec/cabac_functions.h |  8 ++++--
 libavcodec/h264_cabac.c      |  9 +-----
 libavcodec/x86/cabac.h       | 18 +++++++-----
 libavcodec/x86/h264_i386.h   | 24 +++++++++++-----
 6 files changed, 70 insertions(+), 48 deletions(-)

diff --git a/libavcodec/cabac.c b/libavcodec/cabac.c
index 4afcafb52b..bd7d9494b3 100644
--- a/libavcodec/cabac.c
+++ b/libavcodec/cabac.c
@@ -31,6 +31,29 @@
 #include "cabac.h"
 #include "cabac_functions.h"
 
+uint8_t ff_h264_cabac_tables[512 + 4*2*64 + 4*64 + 63] = {
+ 9,8,7,7,6,6,6,6,5,5,5,5,5,5,5,5,
+ 4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,
+ 3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,
+ 3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,
+ 2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,
+ 2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,
+ 2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,
+ 2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,
+ 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
+ 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
+ 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
+ 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
+ 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
+ 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
+ 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
+ 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
+ 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
+ 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
+ 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
+ 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
+};
+
 static const uint8_t lps_range[64][4]= {
 {128,176,208,240}, {128,167,197,227}, {128,158,187,216}, {123,150,178,205},
 {116,142,169,195}, {111,135,160,185}, {105,128,152,175}, {100,122,144,166},
@@ -50,8 +73,6 @@ static const uint8_t lps_range[64][4]= {
 {  6,  8,  9, 11}, {  6,  7,  9, 10}, {  6,  7,  8,  9}, {  2,  2,  2,  2},
 };
 
-uint8_t ff_h264_mlps_state[4*64];
-uint8_t ff_h264_lps_range[4*2*64];
 static uint8_t h264_mps_state[2 * 64];
 
 static const uint8_t mps_state[64]= {
@@ -76,27 +97,11 @@ static const uint8_t lps_state[64]= {
  36,36,37,37,37,38,38,63,
 };
 
-const uint8_t ff_h264_norm_shift[512]= {
- 9,8,7,7,6,6,6,6,5,5,5,5,5,5,5,5,
- 4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,
- 3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,
- 3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,
- 2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,
- 2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,
- 2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,
- 2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,
- 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
- 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
- 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
- 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
- 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
- 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
- 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
- 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
- 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
- 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
- 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
- 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
+static const uint8_t last_coeff_flag_offset_8x8[63] = {
+ 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+ 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+ 3, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4,
+ 5, 5, 5, 5, 6, 6, 6, 6, 7, 7, 7, 7, 8, 8, 8
 };
 
 /**
@@ -153,6 +158,9 @@ void ff_init_cabac_states(CABACContext *c){
             ff_h264_mlps_state[128-2*i-2]= 0;
         }
     }
+    for(i=0; i< 63; i++){
+      ff_h264_last_coeff_flag_offset_8x8[i] = last_coeff_flag_offset_8x8[i];
+    }
 }
 
 #ifdef TEST
diff --git a/libavcodec/cabac.h b/libavcodec/cabac.h
index 5a99f0b2fe..1f1c943262 100644
--- a/libavcodec/cabac.h
+++ b/libavcodec/cabac.h
@@ -31,6 +31,11 @@
 
 #include "put_bits.h"
 
+#define H264_NORM_SHIFT_OFFSET 0
+#define H264_LPS_RANGE_OFFSET 512
+#define H264_MLPS_STATE_OFFSET 1024
+#define H264_LAST_COEFF_FLAG_OFFSET_8x8_OFFSET 1280
+
 #define CABAC_BITS 16
 #define CABAC_MASK ((1<<CABAC_BITS)-1)
 
diff --git a/libavcodec/cabac_functions.h b/libavcodec/cabac_functions.h
index 4c74cf7b23..484ba85db6 100644
--- a/libavcodec/cabac_functions.h
+++ b/libavcodec/cabac_functions.h
@@ -36,9 +36,11 @@
 #   include "x86/cabac.h"
 #endif
 
-extern const uint8_t ff_h264_norm_shift[512];
-extern uint8_t ff_h264_mlps_state[4*64];
-extern uint8_t ff_h264_lps_range[4*2*64];  ///< rangeTabLPS
+extern uint8_t ff_h264_cabac_tables[512 + 4*2*64 + 4*64 + 63];
+static uint8_t * const ff_h264_norm_shift = ff_h264_cabac_tables + H264_NORM_SHIFT_OFFSET;
+static uint8_t * const ff_h264_lps_range = ff_h264_cabac_tables + H264_LPS_RANGE_OFFSET;
+static uint8_t * const ff_h264_mlps_state = ff_h264_cabac_tables + H264_MLPS_STATE_OFFSET;
+static uint8_t * const ff_h264_last_coeff_flag_offset_8x8 = ff_h264_cabac_tables + H264_LAST_COEFF_FLAG_OFFSET_8x8_OFFSET;
 
 static void refill(CABACContext *c){
 #if CABAC_BITS == 16
diff --git a/libavcodec/h264_cabac.c b/libavcodec/h264_cabac.c
index 9e1cf1b520..f27e72faf0 100644
--- a/libavcodec/h264_cabac.c
+++ b/libavcodec/h264_cabac.c
@@ -1560,13 +1560,6 @@ static av_always_inline int get_cabac_cbf_ctx( H264Context *h, int cat, int idx,
     return base_ctx[cat] + ctx;
 }
 
-DECLARE_ASM_CONST(1, uint8_t, last_coeff_flag_offset_8x8)[63] = {
-    0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
-    2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
-    3, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4,
-    5, 5, 5, 5, 6, 6, 6, 6, 7, 7, 7, 7, 8, 8, 8
-};
-
 static av_always_inline void
 decode_cabac_residual_internal(H264Context *h, DCTELEM *block,
                                int cat, int n, const uint8_t *scantable,
@@ -1670,7 +1663,7 @@ decode_cabac_residual_internal(H264Context *h, DCTELEM *block,
                                                  last_coeff_ctx_base-significant_coeff_ctx_base);
         }
 #else
-        DECODE_SIGNIFICANCE( 63, sig_off[last], last_coeff_flag_offset_8x8[last] );
+        DECODE_SIGNIFICANCE( 63, sig_off[last], ff_h264_last_coeff_flag_offset_8x8[last] );
     } else {
         if (is_dc && chroma422) { // dc 422
             DECODE_SIGNIFICANCE(7, sig_coeff_offset_dc[last], sig_coeff_offset_dc[last]);
diff --git a/libavcodec/x86/cabac.h b/libavcodec/x86/cabac.h
index c1fc0d1139..32ce2b2762 100644
--- a/libavcodec/x86/cabac.h
+++ b/libavcodec/x86/cabac.h
@@ -24,6 +24,7 @@
 #include "libavcodec/cabac.h"
 #include "libavutil/attributes.h"
 #include "libavutil/x86_cpu.h"
+#include "libavutil/internal.h"
 #include "config.h"
 
 #if HAVE_FAST_CMOV
@@ -51,16 +52,16 @@
         "xor    "tmp"       , "ret"     \n\t"
 #endif /* HAVE_FAST_CMOV */
 
-#define BRANCHLESS_GET_CABAC(ret, statep, low, lowword, range, tmp, tmpbyte, byte, end) \
+#define BRANCHLESS_GET_CABAC(ret, statep, low, lowword, range, tmp, tmpbyte, byte, end, norm_off, lps_off, mlps_off) \
         "movzbl "statep"    , "ret"                                     \n\t"\
         "mov    "range"     , "tmp"                                     \n\t"\
         "and    $0xC0       , "range"                                   \n\t"\
-        "movzbl "MANGLE(ff_h264_lps_range)"("ret", "range", 2), "range" \n\t"\
+        "movzbl "MANGLE(ff_h264_cabac_tables)"+"lps_off"("ret", "range", 2), "range" \n\t"\
         "sub    "range"     , "tmp"                                     \n\t"\
         BRANCHLESS_GET_CABAC_UPDATE(ret, low, range, tmp)                    \
-        "movzbl " MANGLE(ff_h264_norm_shift) "("range"), %%ecx          \n\t"\
+        "movzbl "MANGLE(ff_h264_cabac_tables)"+"norm_off"("range"), %%ecx    \n\t"\
         "shl    %%cl        , "range"                                   \n\t"\
-        "movzbl "MANGLE(ff_h264_mlps_state)"+128("ret"), "tmp"          \n\t"\
+        "movzbl "MANGLE(ff_h264_cabac_tables)"+"mlps_off"+128("ret"), "tmp"  \n\t"\
         "shl    %%cl        , "low"                                     \n\t"\
         "mov    "tmpbyte"   , "statep"                                  \n\t"\
         "test   "lowword"   , "lowword"                                 \n\t"\
@@ -76,7 +77,7 @@
         "shr    $15         , %%ecx                                     \n\t"\
         "bswap  "tmp"                                                   \n\t"\
         "shr    $15         , "tmp"                                     \n\t"\
-        "movzbl " MANGLE(ff_h264_norm_shift) "(%%ecx), %%ecx            \n\t"\
+        "movzbl "MANGLE(ff_h264_cabac_tables)"+"norm_off"(%%ecx), %%ecx \n\t"\
         "sub    $0xFFFF     , "tmp"                                     \n\t"\
         "neg    %%ecx                                                   \n\t"\
         "add    $7          , %%ecx                                     \n\t"\
@@ -94,11 +95,14 @@ static av_always_inline int get_cabac_inline_x86(CABACContext *c,
     __asm__ volatile(
         BRANCHLESS_GET_CABAC("%0", "(%4)", "%1", "%w1",
                              "%2", "%3", "%b3",
-                             "%a6(%5)", "%a7(%5)")
+                             "%a6(%5)", "%a7(%5)", "%a8", "%a9", "%a10")
         : "=&r"(bit), "+&r"(c->low), "+&r"(c->range), "=&q"(tmp)
         : "r"(state), "r"(c),
           "i"(offsetof(CABACContext, bytestream)),
-          "i"(offsetof(CABACContext, bytestream_end))
+          "i"(offsetof(CABACContext, bytestream_end)),
+          "i"(H264_NORM_SHIFT_OFFSET),
+          "i"(H264_LPS_RANGE_OFFSET),
+          "i"(H264_MLPS_STATE_OFFSET)
         : "%"REG_c, "memory"
     );
     return bit & 1;
diff --git a/libavcodec/x86/h264_i386.h b/libavcodec/x86/h264_i386.h
index e849a3d90c..add795e285 100644
--- a/libavcodec/x86/h264_i386.h
+++ b/libavcodec/x86/h264_i386.h
@@ -45,12 +45,13 @@ static int decode_significance_x86(CABACContext *c, int max_coeff,
     int minusindex= 4-(intptr_t)index;
     int bit;
     x86_reg coeff_count;
+
     __asm__ volatile(
         "3:                                     \n\t"
 
         BRANCHLESS_GET_CABAC("%4", "(%1)", "%3", "%w3",
                              "%5", "%k0", "%b0",
-                             "%a11(%6)", "%a12(%6)")
+                             "%a11(%6)", "%a12(%6)", "%a13", "%a14", "%a15")
 
         "test $1, %4                            \n\t"
         " jz 4f                                 \n\t"
@@ -58,7 +59,7 @@ static int decode_significance_x86(CABACContext *c, int max_coeff,
 
         BRANCHLESS_GET_CABAC("%4", "(%1)", "%3", "%w3",
                              "%5", "%k0", "%b0",
-                             "%a11(%6)", "%a12(%6)")
+                             "%a11(%6)", "%a12(%6)", "%a13", "%a14", "%a15")
 
         "sub  %10, %1                           \n\t"
         "mov  %2, %0                            \n\t"
@@ -86,7 +87,10 @@ static int decode_significance_x86(CABACContext *c, int max_coeff,
           "+&r"(c->low), "=&r"(bit), "+&r"(c->range)
         : "r"(c), "m"(minusstart), "m"(end), "m"(minusindex), "m"(last_off),
           "i"(offsetof(CABACContext, bytestream)),
-          "i"(offsetof(CABACContext, bytestream_end))
+          "i"(offsetof(CABACContext, bytestream_end)),
+          "i"(H264_NORM_SHIFT_OFFSET),
+          "i"(H264_LPS_RANGE_OFFSET),
+          "i"(H264_MLPS_STATE_OFFSET)
         : "%"REG_c, "memory"
     );
     return coeff_count;
@@ -100,6 +104,7 @@ static int decode_significance_8x8_x86(CABACContext *c,
     x86_reg coeff_count;
     x86_reg last=0;
     x86_reg state;
+
     __asm__ volatile(
         "mov %1, %6                             \n\t"
         "3:                                     \n\t"
@@ -110,18 +115,19 @@ static int decode_significance_8x8_x86(CABACContext *c,
 
         BRANCHLESS_GET_CABAC("%4", "(%6)", "%3", "%w3",
                              "%5", "%k0", "%b0",
-                             "%a12(%7)", "%a13(%7)")
+                             "%a12(%7)", "%a13(%7)", "%a14", "%a15", "%a16")
 
         "mov %1, %k6                            \n\t"
         "test $1, %4                            \n\t"
         " jz 4f                                 \n\t"
 
-        "movzbl "MANGLE(last_coeff_flag_offset_8x8)"(%k6), %k6\n\t"
+        "movzbl "MANGLE(ff_h264_cabac_tables)"+%a17(%k6), %k6\n\t"
+
         "add %11, %6                            \n\t"
 
         BRANCHLESS_GET_CABAC("%4", "(%6)", "%3", "%w3",
                              "%5", "%k0", "%b0",
-                             "%a12(%7)", "%a13(%7)")
+                             "%a12(%7)", "%a13(%7)", "%a14", "%a15", "%a16")
 
         "mov %2, %0                             \n\t"
         "mov %1, %k6                            \n\t"
@@ -147,7 +153,11 @@ static int decode_significance_8x8_x86(CABACContext *c,
         : "r"(c), "m"(minusindex), "m"(significant_coeff_ctx_base),
           "m"(sig_off), "m"(last_coeff_ctx_base),
           "i"(offsetof(CABACContext, bytestream)),
-          "i"(offsetof(CABACContext, bytestream_end))
+          "i"(offsetof(CABACContext, bytestream_end)),
+          "i"(H264_NORM_SHIFT_OFFSET),
+          "i"(H264_LPS_RANGE_OFFSET),
+          "i"(H264_MLPS_STATE_OFFSET),
+          "i"(H264_LAST_COEFF_FLAG_OFFSET_8x8_OFFSET)
         : "%"REG_c, "memory"
     );
     return coeff_count;