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   1 /*
   2  * Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
   3  *
   4  * This file is part of FFmpeg.
   5  *
   6  * FFmpeg is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  *
  11  * FFmpeg is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with FFmpeg; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  19  */
  20
  21 #ifndef AVCODEC_X86_CABAC_H
  22 #define AVCODEC_X86_CABAC_H
  23
  24 #include <stddef.h>
  25
  26 #include "libavcodec/cabac.h"
  27 #include "libavutil/attributes.h"
  28 #include "libavutil/macros.h"
  29 #include "libavutil/x86/asm.h"
  30 #include "config.h"
  31
  32 #if   (defined(__i386) && defined(__clang__) && (__clang_major__<2 || (__clang_major__==2 && __clang_minor__<10)))\
  33    || (                  !defined(__clang__) && defined(__llvm__) && __GNUC__==4 && __GNUC_MINOR__==2 && __GNUC_PATCHLEVEL__<=1)\
  34    || (defined(__INTEL_COMPILER) && defined(_MSC_VER))
  35 #       define BROKEN_COMPILER 1
  36 #else
  37 #       define BROKEN_COMPILER 0
  38 #endif
  39
  40 #if HAVE_INLINE_ASM
  41
  42 #ifndef UNCHECKED_BITSTREAM_READER
  43 #define UNCHECKED_BITSTREAM_READER !CONFIG_SAFE_BITSTREAM_READER
  44 #endif
  45
  46 #if UNCHECKED_BITSTREAM_READER
  47 #define END_CHECK(end) ""
  48 #else
  49 #define END_CHECK(end) \
  50         "cmp    "end"       , %%"FF_REG_c"                              \n\t"\
  51         "jge    1f                                                      \n\t"
  52 #endif
  53
  54 #ifdef BROKEN_RELOCATIONS
  55 #define TABLES_ARG , "r"(tables)
  56
  57 #if HAVE_FAST_CMOV
  58 #define BRANCHLESS_GET_CABAC_UPDATE(ret, retq, low, range, tmp) \
  59         "cmp    "low"       , "tmp"                        \n\t"\
  60         "cmova  %%ecx       , "range"                      \n\t"\
  61         "sbb    %%rcx       , %%rcx                        \n\t"\
  62         "and    %%ecx       , "tmp"                        \n\t"\
  63         "xor    %%rcx       , "retq"                       \n\t"\
  64         "sub    "tmp"       , "low"                        \n\t"
  65 #else /* HAVE_FAST_CMOV */
  66 #define BRANCHLESS_GET_CABAC_UPDATE(ret, retq, low, range, tmp) \
  67 /* P4 Prescott has crappy cmov,sbb,64-bit shift so avoid them */ \
  68         "sub    "low"       , "tmp"                        \n\t"\
  69         "sar    $31         , "tmp"                        \n\t"\
  70         "sub    %%ecx       , "range"                      \n\t"\
  71         "and    "tmp"       , "range"                      \n\t"\
  72         "add    %%ecx       , "range"                      \n\t"\
  73         "shl    $17         , %%ecx                        \n\t"\
  74         "and    "tmp"       , %%ecx                        \n\t"\
  75         "sub    %%ecx       , "low"                        \n\t"\
  76         "xor    "tmp"       , "ret"                        \n\t"\
  77         "movslq "ret"       , "retq"                       \n\t"
  78 #endif /* HAVE_FAST_CMOV */
  79
  80 #define BRANCHLESS_GET_CABAC(ret, retq, statep, low, lowword, range, rangeq, tmp, tmpbyte, byte, end, norm_off, lps_off, mlps_off, tables) \
  81         "movzbl "statep"    , "ret"                                     \n\t"\
  82         "mov    "range"     , "tmp"                                     \n\t"\
  83         "and    $0xC0       , "range"                                   \n\t"\
  84         "lea    ("ret", "range", 2), %%ecx                              \n\t"\
  85         "movzbl "lps_off"("tables", %%rcx), "range"                     \n\t"\
  86         "sub    "range"     , "tmp"                                     \n\t"\
  87         "mov    "tmp"       , %%ecx                                     \n\t"\
  88         "shl    $17         , "tmp"                                     \n\t"\
  89         BRANCHLESS_GET_CABAC_UPDATE(ret, retq, low, range, tmp)              \
  90         "movzbl "norm_off"("tables", "rangeq"), %%ecx                   \n\t"\
  91         "shl    %%cl        , "range"                                   \n\t"\
  92         "movzbl "mlps_off"+128("tables", "retq"), "tmp"                 \n\t"\
  93         "shl    %%cl        , "low"                                     \n\t"\
  94         "mov    "tmpbyte"   , "statep"                                  \n\t"\
  95         "test   "lowword"   , "lowword"                                 \n\t"\
  96         "jnz    2f                                                      \n\t"\
  97         "mov    "byte"      , %%"FF_REG_c"                              \n\t"\
  98         END_CHECK(end)\
  99         "add"FF_OPSIZE" $2  , "byte"                                    \n\t"\
 100         "1:                                                             \n\t"\
 101         "movzwl (%%"FF_REG_c") , "tmp"                                  \n\t"\
 102         "lea    -1("low")   , %%ecx                                     \n\t"\
 103         "xor    "low"       , %%ecx                                     \n\t"\
 104         "shr    $15         , %%ecx                                     \n\t"\
 105         "bswap  "tmp"                                                   \n\t"\
 106         "shr    $15         , "tmp"                                     \n\t"\
 107         "movzbl "norm_off"("tables", %%rcx), %%ecx                      \n\t"\
 108         "sub    $0xFFFF     , "tmp"                                     \n\t"\
 109         "neg    %%ecx                                                   \n\t"\
 110         "add    $7          , %%ecx                                     \n\t"\
 111         "shl    %%cl        , "tmp"                                     \n\t"\
 112         "add    "tmp"       , "low"                                     \n\t"\
 113         "2:                                                             \n\t"
 114
 115 #else /* BROKEN_RELOCATIONS */
 116 #define TABLES_ARG NAMED_CONSTRAINTS_ARRAY_ADD(ff_h264_cabac_tables)
 117 #define RIP_ARG
 118
 119 #if HAVE_FAST_CMOV
 120 #define BRANCHLESS_GET_CABAC_UPDATE(ret, low, range, tmp)\
 121         "mov    "tmp"       , %%ecx     \n\t"\
 122         "shl    $17         , "tmp"     \n\t"\
 123         "cmp    "low"       , "tmp"     \n\t"\
 124         "cmova  %%ecx       , "range"   \n\t"\
 125         "sbb    %%ecx       , %%ecx     \n\t"\
 126         "and    %%ecx       , "tmp"     \n\t"\
 127         "xor    %%ecx       , "ret"     \n\t"\
 128         "sub    "tmp"       , "low"     \n\t"
 129 #else /* HAVE_FAST_CMOV */
 130 #define BRANCHLESS_GET_CABAC_UPDATE(ret, low, range, tmp)\
 131         "mov    "tmp"       , %%ecx     \n\t"\
 132         "shl    $17         , "tmp"     \n\t"\
 133         "sub    "low"       , "tmp"     \n\t"\
 134         "sar    $31         , "tmp"     \n\t" /*lps_mask*/\
 135         "sub    %%ecx       , "range"   \n\t" /*RangeLPS - range*/\
 136         "and    "tmp"       , "range"   \n\t" /*(RangeLPS - range)&lps_mask*/\
 137         "add    %%ecx       , "range"   \n\t" /*new range*/\
 138         "shl    $17         , %%ecx     \n\t"\
 139         "and    "tmp"       , %%ecx     \n\t"\
 140         "sub    %%ecx       , "low"     \n\t"\
 141         "xor    "tmp"       , "ret"     \n\t"
 142 #endif /* HAVE_FAST_CMOV */
 143
 144 #define BRANCHLESS_GET_CABAC(ret, retq, statep, low, lowword, range, rangeq, tmp, tmpbyte, byte, end, norm_off, lps_off, mlps_off, tables) \
 145         "movzbl "statep"    , "ret"                                     \n\t"\
 146         "mov    "range"     , "tmp"                                     \n\t"\
 147         "and    $0xC0       , "range"                                   \n\t"\
 148         "movzbl "MANGLE(ff_h264_cabac_tables)"+"lps_off"("ret", "range", 2), "range" \n\t"\
 149         "sub    "range"     , "tmp"                                     \n\t"\
 150         BRANCHLESS_GET_CABAC_UPDATE(ret, low, range, tmp)                    \
 151         "movzbl "MANGLE(ff_h264_cabac_tables)"+"norm_off"("range"), %%ecx    \n\t"\
 152         "shl    %%cl        , "range"                                   \n\t"\
 153         "movzbl "MANGLE(ff_h264_cabac_tables)"+"mlps_off"+128("ret"), "tmp"  \n\t"\
 154         "shl    %%cl        , "low"                                     \n\t"\
 155         "mov    "tmpbyte"   , "statep"                                  \n\t"\
 156         "test   "lowword"   , "lowword"                                 \n\t"\
 157         " jnz   2f                                                      \n\t"\
 158         "mov    "byte"      , %%"FF_REG_c"                              \n\t"\
 159         END_CHECK(end)\
 160         "add"FF_OPSIZE" $2  , "byte"                                    \n\t"\
 161         "1:                                                             \n\t"\
 162         "movzwl (%%"FF_REG_c") , "tmp"                                  \n\t"\
 163         "lea    -1("low")   , %%ecx                                     \n\t"\
 164         "xor    "low"       , %%ecx                                     \n\t"\
 165         "shr    $15         , %%ecx                                     \n\t"\
 166         "bswap  "tmp"                                                   \n\t"\
 167         "shr    $15         , "tmp"                                     \n\t"\
 168         "movzbl "MANGLE(ff_h264_cabac_tables)"+"norm_off"(%%ecx), %%ecx \n\t"\
 169         "sub    $0xFFFF     , "tmp"                                     \n\t"\
 170         "neg    %%ecx                                                   \n\t"\
 171         "add    $7          , %%ecx                                     \n\t"\
 172         "shl    %%cl        , "tmp"                                     \n\t"\
 173         "add    "tmp"       , "low"                                     \n\t"\
 174         "2:                                                             \n\t"
 175
 176 #endif /* BROKEN_RELOCATIONS */
 177
 178 #if HAVE_7REGS && !BROKEN_COMPILER
 179 #define get_cabac_inline get_cabac_inline_x86
 180 static av_always_inline int get_cabac_inline_x86(CABACContext *c,
 181                                                  uint8_t *const state)
 182 {
 183     int bit, tmp;
 184 #ifdef BROKEN_RELOCATIONS
 185     void *tables;
 186
 187     __asm__ volatile(
 188         "lea    "MANGLE(ff_h264_cabac_tables)", %0      \n\t"
 189         : "=&r"(tables)
 190         : NAMED_CONSTRAINTS_ARRAY(ff_h264_cabac_tables)
 191     );
 192 #endif
 193
 194     __asm__ volatile(
 195         BRANCHLESS_GET_CABAC("%0", "%q0", "(%4)", "%1", "%w1",
 196                              "%2", "%q2", "%3", "%b3",
 197                              "%c6(%5)", "%c7(%5)",
 198                              AV_STRINGIFY(H264_NORM_SHIFT_OFFSET),
 199                              AV_STRINGIFY(H264_LPS_RANGE_OFFSET),
 200                              AV_STRINGIFY(H264_MLPS_STATE_OFFSET),
 201                              "%8")
 202         : "=&r"(bit), "=&r"(c->low), "=&r"(c->range), "=&q"(tmp)
 203         : "r"(state), "r"(c),
 204           "i"(offsetof(CABACContext, bytestream)),
 205           "i"(offsetof(CABACContext, bytestream_end))
 206           TABLES_ARG
 207           ,"1"(c->low), "2"(c->range)
 208         : "%"FF_REG_c, "memory"
 209     );
 210     return bit & 1;
 211 }
 212 #endif /* HAVE_7REGS && !BROKEN_COMPILER */
 213
 214 #if !BROKEN_COMPILER
 215 #define get_cabac_bypass_sign get_cabac_bypass_sign_x86
 216 static av_always_inline int get_cabac_bypass_sign_x86(CABACContext *c, int val)
 217 {
 218     x86_reg tmp;
 219     __asm__ volatile(
 220         "movl        %c6(%2), %k1       \n\t"
 221         "movl        %c3(%2), %%eax     \n\t"
 222         "shl             $17, %k1       \n\t"
 223         "add           %%eax, %%eax     \n\t"
 224         "sub             %k1, %%eax     \n\t"
 225         "cdq                            \n\t"
 226         "and           %%edx, %k1       \n\t"
 227         "add             %k1, %%eax     \n\t"
 228         "xor           %%edx, %%ecx     \n\t"
 229         "sub           %%edx, %%ecx     \n\t"
 230         "test           %%ax, %%ax      \n\t"
 231         "jnz              1f            \n\t"
 232         "mov         %c4(%2), %1        \n\t"
 233         "subl        $0xFFFF, %%eax     \n\t"
 234         "movzwl         (%1), %%edx     \n\t"
 235         "bswap         %%edx            \n\t"
 236         "shrl            $15, %%edx     \n\t"
 237 #if UNCHECKED_BITSTREAM_READER
 238         "add              $2, %1        \n\t"
 239         "addl          %%edx, %%eax     \n\t"
 240         "mov              %1, %c4(%2)   \n\t"
 241 #else
 242         "addl          %%edx, %%eax     \n\t"
 243         "cmp         %c5(%2), %1        \n\t"
 244         "jge              1f            \n\t"
 245         "add"FF_OPSIZE"   $2, %c4(%2)   \n\t"
 246 #endif
 247         "1:                             \n\t"
 248         "movl          %%eax, %c3(%2)   \n\t"
 249
 250         : "+c"(val), "=&r"(tmp)
 251         : "r"(c),
 252           "i"(offsetof(CABACContext, low)),
 253           "i"(offsetof(CABACContext, bytestream)),
 254           "i"(offsetof(CABACContext, bytestream_end)),
 255           "i"(offsetof(CABACContext, range))
 256         : "%eax", "%edx", "memory"
 257     );
 258     return val;
 259 }
 260
 261 #define get_cabac_bypass get_cabac_bypass_x86
 262 static av_always_inline int get_cabac_bypass_x86(CABACContext *c)
 263 {
 264     x86_reg tmp;
 265     int res;
 266     __asm__ volatile(
 267         "movl        %c6(%2), %k1       \n\t"
 268         "movl        %c3(%2), %%eax     \n\t"
 269         "shl             $17, %k1       \n\t"
 270         "add           %%eax, %%eax     \n\t"
 271         "sub             %k1, %%eax     \n\t"
 272         "cdq                            \n\t"
 273         "and           %%edx, %k1       \n\t"
 274         "add             %k1, %%eax     \n\t"
 275         "inc           %%edx            \n\t"
 276         "test           %%ax, %%ax      \n\t"
 277         "jnz              1f            \n\t"
 278         "mov         %c4(%2), %1        \n\t"
 279         "subl        $0xFFFF, %%eax     \n\t"
 280         "movzwl         (%1), %%ecx     \n\t"
 281         "bswap         %%ecx            \n\t"
 282         "shrl            $15, %%ecx     \n\t"
 283         "addl          %%ecx, %%eax     \n\t"
 284         "cmp         %c5(%2), %1        \n\t"
 285         "jge              1f            \n\t"
 286         "add"FF_OPSIZE"   $2, %c4(%2)   \n\t"
 287         "1:                             \n\t"
 288         "movl          %%eax, %c3(%2)   \n\t"
 289
 290         : "=&d"(res), "=&r"(tmp)
 291         : "r"(c),
 292           "i"(offsetof(CABACContext, low)),
 293           "i"(offsetof(CABACContext, bytestream)),
 294           "i"(offsetof(CABACContext, bytestream_end)),
 295           "i"(offsetof(CABACContext, range))
 296         : "%eax", "%ecx", "memory"
 297     );
 298     return res;
 299 }
 300 #endif /* !BROKEN_COMPILER */
 301
 302 #endif /* HAVE_INLINE_ASM */
 303 #endif /* AVCODEC_X86_CABAC_H */