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_ARM_CABAC_H
20 #define AVCODEC_ARM_CABAC_H
21
22 #include "config.h"
23 #if HAVE_ARMV6T2_INLINE
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_arm
get_cabac_inline_arm(CABACContext * c,uint8_t * const state)30 static av_always_inline int get_cabac_inline_arm(CABACContext *c,
31 uint8_t *const state)
32 {
33 int bit;
34 void *reg_b, *reg_c, *tmp;
35
36 __asm__ volatile(
37 "ldrb %[bit] , [%[state]] \n\t"
38 "add %[r_b] , %[tables] , %[lps_off] \n\t"
39 "mov %[tmp] , %[range] \n\t"
40 "and %[range] , %[range] , #0xC0 \n\t"
41 "add %[r_b] , %[r_b] , %[bit] \n\t"
42 "ldrb %[range] , [%[r_b], %[range], lsl #1] \n\t"
43 "add %[r_b] , %[tables] , %[norm_off] \n\t"
44 "sub %[r_c] , %[tmp] , %[range] \n\t"
45 "lsl %[tmp] , %[r_c] , #17 \n\t"
46 "cmp %[tmp] , %[low] \n\t"
47 "it gt \n\t"
48 "movgt %[range] , %[r_c] \n\t"
49 "itt cc \n\t"
50 "mvncc %[bit] , %[bit] \n\t"
51 "subcc %[low] , %[low] , %[tmp] \n\t"
52 "add %[r_c] , %[tables] , %[mlps_off] \n\t"
53 "ldrb %[tmp] , [%[r_b], %[range]] \n\t"
54 "ldrb %[r_b] , [%[r_c], %[bit]] \n\t"
55 "lsl %[low] , %[low] , %[tmp] \n\t"
56 "lsl %[range] , %[range] , %[tmp] \n\t"
57 "uxth %[r_c] , %[low] \n\t"
58 "strb %[r_b] , [%[state]] \n\t"
59 "tst %[r_c] , %[r_c] \n\t"
60 "bne 2f \n\t"
61 "ldr %[r_c] , [%[c], %[byte]] \n\t"
62 #if UNCHECKED_BITSTREAM_READER
63 "ldrh %[tmp] , [%[r_c]] \n\t"
64 "add %[r_c] , %[r_c] , #2 \n\t"
65 "str %[r_c] , [%[c], %[byte]] \n\t"
66 #else
67 "ldr %[r_b] , [%[c], %[end]] \n\t"
68 "ldrh %[tmp] , [%[r_c]] \n\t"
69 "cmp %[r_c] , %[r_b] \n\t"
70 "itt lt \n\t"
71 "addlt %[r_c] , %[r_c] , #2 \n\t"
72 "strlt %[r_c] , [%[c], %[byte]] \n\t"
73 #endif
74 "sub %[r_c] , %[low] , #1 \n\t"
75 "add %[r_b] , %[tables] , %[norm_off] \n\t"
76 "eor %[r_c] , %[low] , %[r_c] \n\t"
77 "rev %[tmp] , %[tmp] \n\t"
78 "lsr %[r_c] , %[r_c] , #15 \n\t"
79 "lsr %[tmp] , %[tmp] , #15 \n\t"
80 "ldrb %[r_c] , [%[r_b], %[r_c]] \n\t"
81 "movw %[r_b] , #0xFFFF \n\t"
82 "sub %[tmp] , %[tmp] , %[r_b] \n\t"
83 "rsb %[r_c] , %[r_c] , #7 \n\t"
84 "lsl %[tmp] , %[tmp] , %[r_c] \n\t"
85 "add %[low] , %[low] , %[tmp] \n\t"
86 "2: \n\t"
87 : [bit]"=&r"(bit),
88 [low]"+&r"(c->low),
89 [range]"+&r"(c->range),
90 [r_b]"=&r"(reg_b),
91 [r_c]"=&r"(reg_c),
92 [tmp]"=&r"(tmp)
93 : [c]"r"(c),
94 [state]"r"(state),
95 [tables]"r"(ff_h264_cabac_tables),
96 [byte]"M"(offsetof(CABACContext, bytestream)),
97 [end]"M"(offsetof(CABACContext, bytestream_end)),
98 [norm_off]"I"(H264_NORM_SHIFT_OFFSET),
99 [lps_off]"I"(H264_LPS_RANGE_OFFSET),
100 [mlps_off]"I"(H264_MLPS_STATE_OFFSET + 128)
101 : "memory", "cc"
102 );
103
104 return bit & 1;
105 }
106 #endif /* HAVE_ARMV6T2_INLINE */
107
108 #endif /* AVCODEC_ARM_CABAC_H */
109