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ffmpeg / libavcodec / ppc / fft_altivec.c @ 187a5379

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/*
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 * FFT/IFFT transforms
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 * AltiVec-enabled
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 * Copyright (c) 2009 Loren Merritt
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 *
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 * This file is part of Libav.
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 *
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 * Libav is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; either
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 * version 2.1 of the License, or (at your option) any later version.
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 *
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 * Libav is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with Libav; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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 */
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#include "libavcodec/fft.h"
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#include "util_altivec.h"
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#include "types_altivec.h"
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/**
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 * Do a complex FFT with the parameters defined in ff_fft_init(). The
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 * input data must be permuted before with s->revtab table. No
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 * 1.0/sqrt(n) normalization is done.
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 * AltiVec-enabled
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 * This code assumes that the 'z' pointer is 16 bytes-aligned
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 * It also assumes all FFTComplex are 8 bytes-aligned pair of float
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 */
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void ff_fft_calc_altivec(FFTContext *s, FFTComplex *z);
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void ff_fft_calc_interleave_altivec(FFTContext *s, FFTComplex *z);
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#if HAVE_GNU_AS
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static void ff_imdct_half_altivec(FFTContext *s, FFTSample *output, const FFTSample *input)
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{
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    int j, k;
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    int n = 1 << s->mdct_bits;
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    int n4 = n >> 2;
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    int n8 = n >> 3;
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    int n32 = n >> 5;
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    const uint16_t *revtabj = s->revtab;
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    const uint16_t *revtabk = s->revtab+n4;
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    const vec_f *tcos = (const vec_f*)(s->tcos+n8);
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    const vec_f *tsin = (const vec_f*)(s->tsin+n8);
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    const vec_f *pin = (const vec_f*)(input+n4);
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    vec_f *pout = (vec_f*)(output+n4);
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    /* pre rotation */
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    k = n32-1;
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    do {
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        vec_f cos,sin,cos0,sin0,cos1,sin1,re,im,r0,i0,r1,i1,a,b,c,d;
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#define CMULA(p,o0,o1,o2,o3)\
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        a = pin[ k*2+p];                       /* { z[k].re,    z[k].im,    z[k+1].re,  z[k+1].im  } */\
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        b = pin[-k*2-p-1];                     /* { z[-k-2].re, z[-k-2].im, z[-k-1].re, z[-k-1].im } */\
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        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 } */\
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        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    } */\
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        cos = vec_perm(cos0, cos1, vcprm(o0,o1,s##o2,s##o3)); /* { cos[k], cos[k+1], cos[-k-2], cos[-k-1] } */\
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        sin = vec_perm(sin0, sin1, vcprm(o0,o1,s##o2,s##o3));\
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        r##p = im*cos - re*sin;\
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        i##p = re*cos + im*sin;
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#define STORE2(v,dst)\
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        j = dst;\
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        vec_ste(v, 0, output+j*2);\
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        vec_ste(v, 4, output+j*2);
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#define STORE8(p)\
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        a = vec_perm(r##p, i##p, vcprm(0,s0,0,s0));\
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        b = vec_perm(r##p, i##p, vcprm(1,s1,1,s1));\
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        c = vec_perm(r##p, i##p, vcprm(2,s2,2,s2));\
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        d = vec_perm(r##p, i##p, vcprm(3,s3,3,s3));\
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        STORE2(a, revtabk[ p*2-4]);\
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        STORE2(b, revtabk[ p*2-3]);\
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        STORE2(c, revtabj[-p*2+2]);\
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        STORE2(d, revtabj[-p*2+3]);
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        cos0 = tcos[k];
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        sin0 = tsin[k];
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        cos1 = tcos[-k-1];
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        sin1 = tsin[-k-1];
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        CMULA(0, 0,1,2,3);
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        CMULA(1, 2,3,0,1);
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        STORE8(0);
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        STORE8(1);
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        revtabj += 4;
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        revtabk -= 4;
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        k--;
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    } while(k >= 0);
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    ff_fft_calc_altivec(s, (FFTComplex*)output);
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    /* post rotation + reordering */
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    j = -n32;
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    k = n32-1;
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    do {
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        vec_f cos,sin,re,im,a,b,c,d;
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#define CMULB(d0,d1,o)\
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        re = pout[o*2];\
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        im = pout[o*2+1];\
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        cos = tcos[o];\
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        sin = tsin[o];\
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        d0 = im*sin - re*cos;\
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        d1 = re*sin + im*cos;
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        CMULB(a,b,j);
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        CMULB(c,d,k);
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        pout[2*j]   = vec_perm(a, d, vcprm(0,s3,1,s2));
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        pout[2*j+1] = vec_perm(a, d, vcprm(2,s1,3,s0));
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        pout[2*k]   = vec_perm(c, b, vcprm(0,s3,1,s2));
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        pout[2*k+1] = vec_perm(c, b, vcprm(2,s1,3,s0));
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        j++;
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        k--;
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    } while(k >= 0);
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}
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static void ff_imdct_calc_altivec(FFTContext *s, FFTSample *output, const FFTSample *input)
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{
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    int k;
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    int n = 1 << s->mdct_bits;
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    int n4 = n >> 2;
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    int n16 = n >> 4;
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    vec_u32 sign = {1U<<31,1U<<31,1U<<31,1U<<31};
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    vec_u32 *p0 = (vec_u32*)(output+n4);
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    vec_u32 *p1 = (vec_u32*)(output+n4*3);
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    ff_imdct_half_altivec(s, output+n4, input);
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    for (k = 0; k < n16; k++) {
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        vec_u32 a = p0[k] ^ sign;
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        vec_u32 b = p1[-k-1];
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        p0[-k-1] = vec_perm(a, a, vcprm(3,2,1,0));
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        p1[k]    = vec_perm(b, b, vcprm(3,2,1,0));
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    }
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}
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#endif /* HAVE_GNU_AS */
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av_cold void ff_fft_init_altivec(FFTContext *s)
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{
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#if HAVE_GNU_AS
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    s->fft_calc   = ff_fft_calc_interleave_altivec;
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    s->imdct_calc = ff_imdct_calc_altivec;
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    s->imdct_half = ff_imdct_half_altivec;
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#endif
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}