misc typo, style and wording fixes
[ffmpeg.git] / libavcodec / arm / ac3dsp_armv6.S
1 /*
2  * Copyright (c) 2011 Mans Rullgard <mans@mansr.com>
3  *
4  * This file is part of Libav.
5  *
6  * Libav is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU Lesser General Public
8  * License as published by the Free Software Foundation; either
9  * version 2.1 of the License, or (at your option) any later version.
10  *
11  * Libav is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14  * Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public
17  * License along with Libav; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19  */
20
21 #include "libavutil/arm/asm.S"
22
23 function ff_ac3_bit_alloc_calc_bap_armv6, export=1
24         ldr             r12, [sp]
25         cmp             r12, #-960
26         beq             4f
27         push            {r4-r11,lr}
28         add             r5,  sp,  #40
29         movrelx         r4,  X(ff_ac3_bin_to_band_tab), r11
30         movrelx         lr,  X(ff_ac3_band_start_tab)
31         ldm             r5,  {r5-r7}
32         ldrb            r4,  [r4, r2]
33         add             r1,  r1,  r2,  lsl #1           @ psd + start
34         add             r0,  r0,  r4,  lsl #1           @ mask + band
35         add             r4,  r4,  lr
36         add             r7,  r7,  r2                    @ bap + start
37 1:
38         ldrsh           r9,  [r0], #2                   @ mask[band]
39         mov             r8,  #0xff0
40         sub             r9,  r9,  r12                   @   - snr_offset
41         ldrb            r10, [r4, #1]!                  @ band_start_tab[++band]
42         subs            r9,  r9,  r5                    @   - floor
43         it              lt
44         movlt           r9,  #0
45         cmp             r10, r3                         @   - end
46         and             r9,  r9,  r8, lsl #1            @   & 0x1fe0
47         ite             gt
48         subgt           r8,  r3,  r2
49         suble           r8,  r10, r2
50         mov             r2,  r10
51         add             r9,  r9,  r5                    @   + floor => m
52         tst             r8,  #1
53         add             r11, r7,  r8
54         bne             3f
55         b               5f
56 2:
57         ldrsh           r8,  [r1], #2
58         ldrsh           lr,  [r1], #2
59         sub             r8,  r8,  r9
60         sub             lr,  lr,  r9
61         usat            r8,  #6,  r8,  asr #5           @ address
62         usat            lr,  #6,  lr,  asr #5
63         ldrb            r8,  [r6, r8]                   @ bap_tab[address]
64         ldrb            lr,  [r6, lr]
65         strb            r8,  [r7], #1                   @ bap[bin]
66         strb            lr,  [r7], #1
67 5:      cmp             r7,  r11
68         blo             2b
69         cmp             r3,  r10
70         bgt             1b
71         pop             {r4-r11,pc}
72 3:
73         ldrsh           r8,  [r1], #2                   @ psd[bin]
74         sub             r8,  r8,  r9                    @   - m
75         usat            r8,  #6,  r8,  asr #5           @ address
76         ldrb            r8,  [r6, r8]                   @ bap_tab[address]
77         strb            r8,  [r7], #1                   @ bap[bin]
78         b               5b
79 4:
80         ldr             r0,  [sp, #12]
81         mov             r1,  #0
82         mov             r2,  #256
83         b               X(memset)
84 endfunc