From 7f668cd2b5f13afa0de9f593948ce2f703ab5aaa Mon Sep 17 00:00:00 2001
From: Roland Scheidegger <rscheidegger_lists@hispeed.ch>
Date: Fri, 27 Apr 2012 22:12:19 +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: Michael Niedermayer <michaelni@gmx.at>
---
 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 196e548327..14ef30a758 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_lps_state[2*64];
 static uint8_t h264_mps_state[2*64];
 
@@ -77,27 +98,11 @@ 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
 };
 
 /**
@@ -158,6 +163,9 @@ 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 667489ede8..29535d08aa 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 90af15c243..ee70fcf985 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 65f2cb4dc8..29dbd7aa6e 100644
--- a/libavcodec/h264_cabac.c
+++ b/libavcodec/h264_cabac.c
@@ -1561,13 +1561,6 @@ 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 fee63d319b..f532be3d8e 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"\
@@ -73,7 +74,7 @@
         "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"\
@@ -93,11 +94,14 @@ 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 6aa2d073e3..d2787087cf 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;