cabac.h 4.93 KB
Newer Older
1
/*
2
 * This file is part of FFmpeg.
3
 *
4
 * FFmpeg is free software; you can redistribute it and/or
5 6 7 8
 * 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.
 *
9
 * FFmpeg is distributed in the hope that it will be useful,
10 11 12 13 14
 * 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
15
 * License along with FFmpeg; if not, write to the Free Software
16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#ifndef AVCODEC_AARCH64_CABAC_H
#define AVCODEC_AARCH64_CABAC_H

#include "config.h"
#if HAVE_INLINE_ASM

#include "libavutil/attributes.h"
#include "libavutil/internal.h"
#include "libavcodec/cabac.h"

#define get_cabac_inline get_cabac_inline_aarch64
static av_always_inline int get_cabac_inline_aarch64(CABACContext *c,
                                                     uint8_t *const state)
{
    int bit;
    void *reg_a, *reg_b, *reg_c, *tmp;

    __asm__ volatile(
        "ldrb       %w[bit]       , [%[state]]                  \n\t"
        "add        %[r_b]        , %[tables]   , %[lps_off]    \n\t"
        "mov        %w[tmp]       , %w[range]                   \n\t"
        "and        %w[range]     , %w[range]   , #0xC0         \n\t"
        "lsl        %w[r_c]       , %w[range]   , #1            \n\t"
        "add        %[r_b]        , %[r_b]      , %w[bit], UXTW \n\t"
        "ldrb       %w[range]     , [%[r_b], %w[r_c], SXTW]     \n\t"
        "sub        %w[r_c]       , %w[tmp]     , %w[range]     \n\t"
        "lsl        %w[tmp]       , %w[r_c]     , #17           \n\t"
        "cmp        %w[tmp]       , %w[low]                     \n\t"
        "csel       %w[tmp]       , %w[tmp]     , wzr      , cc \n\t"
        "csel       %w[range]     , %w[r_c]     , %w[range], gt \n\t"
        "cinv       %w[bit]       , %w[bit]     , cc            \n\t"
        "sub        %w[low]       , %w[low]     , %w[tmp]       \n\t"
        "add        %[r_b]        , %[tables]   , %[norm_off]   \n\t"
        "add        %[r_a]        , %[tables]   , %[mlps_off]   \n\t"
        "ldrb       %w[tmp]       , [%[r_b], %w[range], SXTW]   \n\t"
        "ldrb       %w[r_a]       , [%[r_a], %w[bit], SXTW]     \n\t"
        "lsl        %w[low]       , %w[low]     , %w[tmp]       \n\t"
        "lsl        %w[range]     , %w[range]   , %w[tmp]       \n\t"
        "uxth       %w[r_c]       , %w[low]                     \n\t"
        "strb       %w[r_a]       , [%[state]]                  \n\t"
        "cbnz       %w[r_c]       , 2f                          \n\t"
        "ldr        %[r_c]        , [%[c], %[byte]]             \n\t"
        "ldr        %[r_a]        , [%[c], %[end]]              \n\t"
        "ldrh       %w[tmp]       , [%[r_c]]                    \n\t"
        "cmp        %[r_c]        , %[r_a]                      \n\t"
        "b.ge       1f                                          \n\t"
        "add        %[r_a]        , %[r_c]      , #2            \n\t"
        "str        %[r_a]        , [%[c], %[byte]]             \n\t"
        "1:                                                     \n\t"
        "sub        %w[r_c]       , %w[low]     , #1            \n\t"
        "eor        %w[r_c]       , %w[r_c]     , %w[low]       \n\t"
        "rev        %w[tmp]       , %w[tmp]                     \n\t"
        "lsr        %w[r_c]       , %w[r_c]     , #15           \n\t"
        "lsr        %w[tmp]       , %w[tmp]     , #15           \n\t"
        "ldrb       %w[r_c]       , [%[r_b], %w[r_c], SXTW]     \n\t"
        "mov        %w[r_b]       , #0xFFFF                     \n\t"
        "mov        %w[r_a]       , #7                          \n\t"
        "sub        %w[tmp]       , %w[tmp]     , %w[r_b]       \n\t"
        "sub        %w[r_c]       , %w[r_a]     , %w[r_c]       \n\t"
        "lsl        %w[tmp]       , %w[tmp]     , %w[r_c]       \n\t"
        "add        %w[low]       , %w[low]     , %w[tmp]       \n\t"
        "2:                                                     \n\t"
        :    [bit]"=&r"(bit),
             [low]"+&r"(c->low),
           [range]"+&r"(c->range),
             [r_a]"=&r"(reg_a),
             [r_b]"=&r"(reg_b),
             [r_c]"=&r"(reg_c),
             [tmp]"=&r"(tmp)
        :        [c]"r"(c),
             [state]"r"(state),
            [tables]"r"(ff_h264_cabac_tables),
              [byte]"i"(offsetof(CABACContext, bytestream)),
               [end]"i"(offsetof(CABACContext, bytestream_end)),
          [norm_off]"I"(H264_NORM_SHIFT_OFFSET),
           [lps_off]"I"(H264_LPS_RANGE_OFFSET),
          [mlps_off]"I"(H264_MLPS_STATE_OFFSET + 128)
        : "memory", "cc"
        );

    return bit & 1;
}

#endif /* HAVE_INLINE_ASM */

#endif /* AVCODEC_AARCH64_CABAC_H */