aboutsummaryrefslogtreecommitdiffstats
path: root/libavcodec/arm/dsputil_vfp.S
blob: 497c02be929a3af33423a1c932f87f22466c7542 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
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
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
/*
 * Copyright (c) 2008 Siarhei Siamashka <ssvb@users.sourceforge.net>
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg is free software; you can redistribute it and/or
 * 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.
 *
 * FFmpeg is distributed in the hope that it will be useful,
 * 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
 * License along with FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include "config.h"
#include "asm.S"

/*
 * VFP is a floating point coprocessor used in some ARM cores. VFP11 has 1 cycle
 * throughput for almost all the instructions (except for double precision
 * arithmetics), but rather high latency. Latency is 4 cycles for loads and 8 cycles
 * for arithmetic operations. Scheduling code to avoid pipeline stalls is very
 * important for performance. One more interesting feature is that VFP has
 * independent load/store and arithmetics pipelines, so it is possible to make
 * them work simultaneously and get more than 1 operation per cycle. Load/store
 * pipeline can process 2 single precision floating point values per cycle and
 * supports bulk loads and stores for large sets of registers. Arithmetic operations
 * can be done on vectors, which allows to keep the arithmetics pipeline busy,
 * while the processor may issue and execute other instructions. Detailed
 * optimization manuals can be found at http://www.arm.com
 */

/**
 * ARM VFP optimized implementation of 'vector_fmul_c' function.
 * Assume that len is a positive number and is multiple of 8
 */
@ void ff_vector_fmul_vfp(float *dst, const float *src0, const float *src1, int len)
function ff_vector_fmul_vfp, export=1
        vpush           {d8-d15}
        fmrx            r12, fpscr
        orr             r12, r12, #(3 << 16) /* set vector size to 4 */
        fmxr            fpscr, r12

        vldmia          r1!, {s0-s3}
        vldmia          r2!, {s8-s11}
        vldmia          r1!, {s4-s7}
        vldmia          r2!, {s12-s15}
        vmul.f32        s8,  s0,  s8
1:
        subs            r3,  r3,  #16
        vmul.f32        s12, s4,  s12
        vldmiage        r1!, {s16-s19}
        vldmiage        r2!, {s24-s27}
        vldmiage        r1!, {s20-s23}
        vldmiage        r2!, {s28-s31}
        vmulge.f32      s24, s16, s24
        vstmia          r0!, {s8-s11}
        vstmia          r0!, {s12-s15}
        vmulge.f32      s28, s20, s28
        vldmiagt        r1!, {s0-s3}
        vldmiagt        r2!, {s8-s11}
        vldmiagt        r1!, {s4-s7}
        vldmiagt        r2!, {s12-s15}
        vmulge.f32      s8,  s0,  s8
        vstmiage        r0!, {s24-s27}
        vstmiage        r0!, {s28-s31}
        bgt             1b

        bic             r12, r12, #(7 << 16) /* set vector size back to 1 */
        fmxr            fpscr, r12
        vpop            {d8-d15}
        bx              lr
endfunc

/**
 * ARM VFP optimized implementation of 'vector_fmul_reverse_c' function.
 * Assume that len is a positive number and is multiple of 8
 */
@ void ff_vector_fmul_reverse_vfp(float *dst, const float *src0,
@                                 const float *src1, int len)
function ff_vector_fmul_reverse_vfp, export=1
        vpush           {d8-d15}
        add             r2,  r2,  r3, lsl #2
        vldmdb          r2!, {s0-s3}
        vldmia          r1!, {s8-s11}
        vldmdb          r2!, {s4-s7}
        vldmia          r1!, {s12-s15}
        vmul.f32        s8,  s3,  s8
        vmul.f32        s9,  s2,  s9
        vmul.f32        s10, s1,  s10
        vmul.f32        s11, s0,  s11
1:
        subs            r3,  r3,  #16
        vldmdbge        r2!, {s16-s19}
        vmul.f32        s12, s7,  s12
        vldmiage        r1!, {s24-s27}
        vmul.f32        s13, s6,  s13
        vldmdbge        r2!, {s20-s23}
        vmul.f32        s14, s5,  s14
        vldmiage        r1!, {s28-s31}
        vmul.f32        s15, s4,  s15
        vmulge.f32      s24, s19, s24
        vldmdbgt        r2!, {s0-s3}
        vmulge.f32      s25, s18, s25
        vstmia          r0!, {s8-s13}
        vmulge.f32      s26, s17, s26
        vldmiagt        r1!, {s8-s11}
        vmulge.f32      s27, s16, s27
        vmulge.f32      s28, s23, s28
        vldmdbgt        r2!, {s4-s7}
        vmulge.f32      s29, s22, s29
        vstmia          r0!, {s14-s15}
        vmulge.f32      s30, s21, s30
        vmulge.f32      s31, s20, s31
        vmulge.f32      s8,  s3,  s8
        vldmiagt        r1!, {s12-s15}
        vmulge.f32      s9,  s2,  s9
        vmulge.f32      s10, s1,  s10
        vstmiage        r0!, {s24-s27}
        vmulge.f32      s11, s0,  s11
        vstmiage        r0!, {s28-s31}
        bgt             1b

        vpop            {d8-d15}
        bx              lr
endfunc