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
get_cabac_inline_aarch64(CABACContext * c,uint8_t * const state)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 */
105