innoHeim/Rsupport Screen Capture Codec decoder
[ffmpeg.git] / libavcodec / aarch64 / cabac.h
1 /*
2  * This file is part of Libav.
3  *
4  * Libav 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  * Libav 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 Libav; 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 */