aboutsummaryrefslogtreecommitdiffstats
path: root/libavcodec/ppc/fft_altivec.c
blob: e763fe786bb23496db614efbf262679ff439aee3 (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
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
/*
 * FFT/IFFT transforms
 * AltiVec-enabled
 * Copyright (c) 2009 Loren Merritt
 *
 * 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 "libavcodec/fft.h"
#include "util_altivec.h"
#include "types_altivec.h"
#include "regs.h"

/**
 * Do a complex FFT with the parameters defined in ff_fft_init(). The
 * input data must be permuted before with s->revtab table. No
 * 1.0/sqrt(n) normalization is done.
 * AltiVec-enabled
 * This code assumes that the 'z' pointer is 16 bytes-aligned
 * It also assumes all FFTComplex are 8 bytes-aligned pair of float
 */

// Pointers to functions. Not using function pointer syntax, because
// that involves an extra level of indirection on some PPC ABIs.
extern void *ff_fft_dispatch_altivec[2][15];

#if HAVE_GNU_AS
// Convert from simd order to C order.
static void swizzle(vec_f *z, int n)
{
    int i;
    n >>= 1;
    for (i = 0; i < n; i += 2) {
        vec_f re = z[i];
        vec_f im = z[i+1];
        z[i]   = vec_mergeh(re, im);
        z[i+1] = vec_mergel(re, im);
    }
}

static av_always_inline void fft_dispatch(FFTContext *s, FFTComplex *z, int do_swizzle)
{
    register vec_f  v14 __asm__("v14") = {0,0,0,0};
    register vec_f  v15 __asm__("v15") = *(const vec_f*)ff_cos_16;
    register vec_f  v16 __asm__("v16") = {0, 0.38268343, M_SQRT1_2, 0.92387953};
    register vec_f  v17 __asm__("v17") = {-M_SQRT1_2, M_SQRT1_2, M_SQRT1_2,-M_SQRT1_2};
    register vec_f  v18 __asm__("v18") = { M_SQRT1_2, M_SQRT1_2, M_SQRT1_2, M_SQRT1_2};
    register vec_u8 v19 __asm__("v19") = vcprm(s0,3,2,1);
    register vec_u8 v20 __asm__("v20") = vcprm(0,1,s2,s1);
    register vec_u8 v21 __asm__("v21") = vcprm(2,3,s0,s3);
    register vec_u8 v22 __asm__("v22") = vcprm(2,s3,3,s2);
    register vec_u8 v23 __asm__("v23") = vcprm(0,1,s0,s1);
    register vec_u8 v24 __asm__("v24") = vcprm(2,3,s2,s3);
    register vec_u8 v25 __asm__("v25") = vcprm(2,3,0,1);
    register vec_u8 v26 __asm__("v26") = vcprm(1,2,s3,s0);
    register vec_u8 v27 __asm__("v27") = vcprm(0,3,s2,s1);
    register vec_u8 v28 __asm__("v28") = vcprm(0,2,s1,s3);
    register vec_u8 v29 __asm__("v29") = vcprm(1,3,s0,s2);
    register FFTSample *const*cos_tabs __asm__("r12") = ff_cos_tabs;
    register FFTComplex *zarg __asm__("r3") = z;
    __asm__(
        "mtctr %0               \n"
        "li   "r(9)", 16        \n"
        "subi "r(1)","r(1) ",%1 \n"
        "bctrl                  \n"
        "addi "r(1)","r(1) ",%1 \n"
        ::"r"(ff_fft_dispatch_altivec[do_swizzle][s->nbits-2]), "i"(12*sizeof(void*)),
          "r"(zarg), "r"(cos_tabs),
          "v"(v14),"v"(v15),"v"(v16),"v"(v17),"v"(v18),"v"(v19),"v"(v20),"v"(v21),
          "v"(v22),"v"(v23),"v"(v24),"v"(v25),"v"(v26),"v"(v27),"v"(v28),"v"(v29)
        : "lr","ctr","r0","r4","r5","r6","r7","r8","r9","r10","r11",
          "v0","v1","v2","v3","v4","v5","v6","v7","v8","v9","v10","v11","v12","v13"
    );
    if (do_swizzle && s->nbits <= 4)
        swizzle((vec_f*)z, 1<<s->nbits);
}

static void ff_fft_calc_altivec(FFTContext *s, FFTComplex *z)
{
    fft_dispatch(s, z, 1);
}

static void ff_imdct_half_altivec(FFTContext *s, FFTSample *output, const FFTSample *input)
{
    int j, k;
    int n = 1 << s->mdct_bits;
    int n4 = n >> 2;
    int n8 = n >> 3;
    int n32 = n >> 5;
    const uint16_t *revtabj = s->revtab;
    const uint16_t *revtabk = s->revtab+n4;
    const vec_f *tcos = (const vec_f*)(s->tcos+n8);
    const vec_f *tsin = (const vec_f*)(s->tsin+n8);
    const vec_f *pin = (const vec_f*)(input+n4);
    vec_f *pout = (vec_f*)(output+n4);

    /* pre rotation */
    k = n32-1;
    do {
        vec_f cos,sin,cos0,sin0,cos1,sin1,re,im,r0,i0,r1,i1,a,b,c,d;
#define CMULA(p,o0,o1,o2,o3)\
        a = pin[ k*2+p];                       /* { z[k].re,    z[k].im,    z[k+1].re,  z[k+1].im  } */\
        b = pin[-k*2-p-1];                     /* { z[-k-2].re, z[-k-2].im, z[-k-1].re, z[-k-1].im } */\
        re = vec_perm(a, b, vcprm(0,2,s0,s2)); /* { z[k].re,    z[k+1].re,  z[-k-2].re, z[-k-1].re } */\
        im = vec_perm(a, b, vcprm(s3,s1,3,1)); /* { z[-k-1].im, z[-k-2].im, z[k+1].im,  z[k].im    } */\
        cos = vec_perm(cos0, cos1, vcprm(o0,o1,s##o2,s##o3)); /* { cos[k], cos[k+1], cos[-k-2], cos[-k-1] } */\
        sin = vec_perm(sin0, sin1, vcprm(o0,o1,s##o2,s##o3));\
        r##p = im*cos - re*sin;\
        i##p = re*cos + im*sin;
#define STORE2(v,dst)\
        j = dst;\
        vec_ste(v, 0, output+j*2);\
        vec_ste(v, 4, output+j*2);
#define STORE8(p)\
        a = vec_perm(r##p, i##p, vcprm(0,s0,0,s0));\
        b = vec_perm(r##p, i##p, vcprm(1,s1,1,s1));\
        c = vec_perm(r##p, i##p, vcprm(2,s2,2,s2));\
        d = vec_perm(r##p, i##p, vcprm(3,s3,3,s3));\
        STORE2(a, revtabk[ p*2-4]);\
        STORE2(b, revtabk[ p*2-3]);\
        STORE2(c, revtabj[-p*2+2]);\
        STORE2(d, revtabj[-p*2+3]);

        cos0 = tcos[k];
        sin0 = tsin[k];
        cos1 = tcos[-k-1];
        sin1 = tsin[-k-1];
        CMULA(0, 0,1,2,3);
        CMULA(1, 2,3,0,1);
        STORE8(0);
        STORE8(1);
        revtabj += 4;
        revtabk -= 4;
        k--;
    } while(k >= 0);

    fft_dispatch(s, (FFTComplex*)output, 0);

    /* post rotation + reordering */
    j = -n32;
    k = n32-1;
    do {
        vec_f cos,sin,re,im,a,b,c,d;
#define CMULB(d0,d1,o)\
        re = pout[o*2];\
        im = pout[o*2+1];\
        cos = tcos[o];\
        sin = tsin[o];\
        d0 = im*sin - re*cos;\
        d1 = re*sin + im*cos;

        CMULB(a,b,j);
        CMULB(c,d,k);
        pout[2*j]   = vec_perm(a, d, vcprm(0,s3,1,s2));
        pout[2*j+1] = vec_perm(a, d, vcprm(2,s1,3,s0));
        pout[2*k]   = vec_perm(c, b, vcprm(0,s3,1,s2));
        pout[2*k+1] = vec_perm(c, b, vcprm(2,s1,3,s0));
        j++;
        k--;
    } while(k >= 0);
}

static void ff_imdct_calc_altivec(FFTContext *s, FFTSample *output, const FFTSample *input)
{
    int k;
    int n = 1 << s->mdct_bits;
    int n4 = n >> 2;
    int n16 = n >> 4;
    vec_u32 sign = {1<<31,1<<31,1<<31,1<<31};
    vec_u32 *p0 = (vec_u32*)(output+n4);
    vec_u32 *p1 = (vec_u32*)(output+n4*3);

    ff_imdct_half_altivec(s, output+n4, input);

    for (k = 0; k < n16; k++) {
        vec_u32 a = p0[k] ^ sign;
        vec_u32 b = p1[-k-1];
        p0[-k-1] = vec_perm(a, a, vcprm(3,2,1,0));
        p1[k]    = vec_perm(b, b, vcprm(3,2,1,0));
    }
}
#endif /* HAVE_GNU_AS */

av_cold void ff_fft_init_altivec(FFTContext *s)
{
    if (HAVE_GNU_AS) {
        s->fft_calc = ff_fft_calc_altivec;
        s->imdct_calc = ff_imdct_calc_altivec;
        s->imdct_half = ff_imdct_half_altivec;
    }
}