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   1 /*
   2  * This file is part of FFmpeg.
   3  *
   4  * FFmpeg is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Lesser General Public
   6  * License as published by the Free Software Foundation; either
   7  * version 2.1 of the License, or (at your option) any later version.
   8  *
   9  * FFmpeg is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * Lesser General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Lesser General Public
  15  * License along with FFmpeg; if not, write to the Free Software
  16  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  17  */
  18
  19 #ifndef AVCODEC_AARCH64_CABAC_H
  20 #define AVCODEC_AARCH64_CABAC_H
  21
  22 #include "config.h"
  23 #if HAVE_INLINE_ASM
  24
  25 #include "libavutil/attributes.h"
  26 #include "libavutil/internal.h"
  27 #include "libavcodec/cabac.h"
  28
  29 #define get_cabac_inline get_cabac_inline_aarch64
  30 static av_always_inline int get_cabac_inline_aarch64(CABACContext *c,
  31                                                      uint8_t *const state)
  32 {
  33     int bit;
  34     void *reg_a, *reg_b, *reg_c, *tmp;
  35
  36     __asm__ volatile(
  37         "ldrb       %w[bit]       , [%[state]]                  \n\t"
  38         "add        %[r_b]        , %[tables]   , %[lps_off]    \n\t"
  39         "mov        %w[tmp]       , %w[range]                   \n\t"
  40         "and        %w[range]     , %w[range]   , #0xC0         \n\t"
  41         "lsl        %w[r_c]       , %w[range]   , #1            \n\t"
  42         "add        %[r_b]        , %[r_b]      , %w[bit], UXTW \n\t"
  43         "ldrb       %w[range]     , [%[r_b], %w[r_c], SXTW]     \n\t"
  44         "sub        %w[r_c]       , %w[tmp]     , %w[range]     \n\t"
  45         "lsl        %w[tmp]       , %w[r_c]     , #17           \n\t"
  46         "cmp        %w[tmp]       , %w[low]                     \n\t"
  47         "csel       %w[tmp]       , %w[tmp]     , wzr      , cc \n\t"
  48         "csel       %w[range]     , %w[r_c]     , %w[range], gt \n\t"
  49         "cinv       %w[bit]       , %w[bit]     , cc            \n\t"
  50         "sub        %w[low]       , %w[low]     , %w[tmp]       \n\t"
  51         "add        %[r_b]        , %[tables]   , %[norm_off]   \n\t"
  52         "add        %[r_a]        , %[tables]   , %[mlps_off]   \n\t"
  53         "ldrb       %w[tmp]       , [%[r_b], %w[range], SXTW]   \n\t"
  54         "ldrb       %w[r_a]       , [%[r_a], %w[bit], SXTW]     \n\t"
  55         "lsl        %w[low]       , %w[low]     , %w[tmp]       \n\t"
  56         "lsl        %w[range]     , %w[range]   , %w[tmp]       \n\t"
  57         "uxth       %w[r_c]       , %w[low]                     \n\t"
  58         "strb       %w[r_a]       , [%[state]]                  \n\t"
  59         "cbnz       %w[r_c]       , 2f                          \n\t"
  60         "ldr        %[r_c]        , [%[c], %[byte]]             \n\t"
  61         "ldr        %[r_a]        , [%[c], %[end]]              \n\t"
  62         "ldrh       %w[tmp]       , [%[r_c]]                    \n\t"
  63         "cmp        %[r_c]        , %[r_a]                      \n\t"
  64         "b.ge       1f                                          \n\t"
  65         "add        %[r_a]        , %[r_c]      , #2            \n\t"
  66         "str        %[r_a]        , [%[c], %[byte]]             \n\t"
  67         "1:                                                     \n\t"
  68         "sub        %w[r_c]       , %w[low]     , #1            \n\t"
  69         "eor        %w[r_c]       , %w[r_c]     , %w[low]       \n\t"
  70         "rev        %w[tmp]       , %w[tmp]                     \n\t"
  71         "lsr        %w[r_c]       , %w[r_c]     , #15           \n\t"
  72         "lsr        %w[tmp]       , %w[tmp]     , #15           \n\t"
  73         "ldrb       %w[r_c]       , [%[r_b], %w[r_c], SXTW]     \n\t"
  74         "mov        %w[r_b]       , #0xFFFF                     \n\t"
  75         "mov        %w[r_a]       , #7                          \n\t"
  76         "sub        %w[tmp]       , %w[tmp]     , %w[r_b]       \n\t"
  77         "sub        %w[r_c]       , %w[r_a]     , %w[r_c]       \n\t"
  78         "lsl        %w[tmp]       , %w[tmp]     , %w[r_c]       \n\t"
  79         "add        %w[low]       , %w[low]     , %w[tmp]       \n\t"
  80         "2:                                                     \n\t"
  81         :    [bit]"=&r"(bit),
  82              [low]"+&r"(c->low),
  83            [range]"+&r"(c->range),
  84              [r_a]"=&r"(reg_a),
  85              [r_b]"=&r"(reg_b),
  86              [r_c]"=&r"(reg_c),
  87              [tmp]"=&r"(tmp)
  88         :        [c]"r"(c),
  89              [state]"r"(state),
  90             [tables]"r"(ff_h264_cabac_tables),
  91               [byte]"i"(offsetof(CABACContext, bytestream)),
  92                [end]"i"(offsetof(CABACContext, bytestream_end)),
  93           [norm_off]"I"(H264_NORM_SHIFT_OFFSET),
  94            [lps_off]"I"(H264_LPS_RANGE_OFFSET),
  95           [mlps_off]"I"(H264_MLPS_STATE_OFFSET + 128)
  96         : "memory", "cc"
  97         );
  98
  99     return bit & 1;
 100 }
 101
 102 #endif /* HAVE_INLINE_ASM */
 103
 104 #endif /* AVCODEC_AARCH64_CABAC_H */