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ffmpeg / libavcodec / i386 / fft_sse.c @ e1958604

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/*
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 * FFT/MDCT transform with SSE optimizations
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 * Copyright (c) 2002 Fabrice Bellard.
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 *
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 * This library 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 of the License, or (at your option) any later version.
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 *
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 * This library 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 this library; if not, write to the Free Software
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 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
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 */
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#include "../dsputil.h"
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#include <math.h>
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#ifdef HAVE_BUILTIN_VECTOR
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#include <xmmintrin.h>
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static const float p1p1p1m1[4] __attribute__((aligned(16))) = 
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    { 1.0, 1.0, 1.0, -1.0 };
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static const float p1p1m1p1[4] __attribute__((aligned(16))) = 
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    { 1.0, 1.0, -1.0, 1.0 };
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static const float p1p1m1m1[4] __attribute__((aligned(16))) = 
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    { 1.0, 1.0, -1.0, -1.0 };
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#if 0
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static void print_v4sf(const char *str, __m128 a)
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{
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    float *p = (float *)&a;
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    printf("%s: %f %f %f %f\n",
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           str, p[0], p[1], p[2], p[3]);
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}
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#endif
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/* XXX: handle reverse case */
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void fft_calc_sse(FFTContext *s, FFTComplex *z)
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{
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    int ln = s->nbits;
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    int        j, np, np2;
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    int        nblocks, nloops;
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    register FFTComplex *p, *q;
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    FFTComplex *cptr, *cptr1;
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    int k;
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    np = 1 << ln;
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    {
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        __m128 *r, a, b, a1, c1, c2;
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        r = (__m128 *)&z[0];
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        c1 = *(__m128 *)p1p1m1m1;
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        c2 = *(__m128 *)p1p1p1m1;
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        if (s->inverse)
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            c2 = *(__m128 *)p1p1m1p1;
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        else
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            c2 = *(__m128 *)p1p1p1m1;
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        j = (np >> 2);
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        do {
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            a = r[0];
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            b = _mm_shuffle_ps(a, a, _MM_SHUFFLE(1, 0, 3, 2));
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            a = _mm_mul_ps(a, c1);
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            /* do the pass 0 butterfly */
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            a = _mm_add_ps(a, b);
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            a1 = r[1];
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            b = _mm_shuffle_ps(a1, a1, _MM_SHUFFLE(1, 0, 3, 2));
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            a1 = _mm_mul_ps(a1, c1);
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            /* do the pass 0 butterfly */
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            b = _mm_add_ps(a1, b);
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            /* multiply third by -i */
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            b = _mm_shuffle_ps(b, b, _MM_SHUFFLE(2, 3, 1, 0));
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            b = _mm_mul_ps(b, c2);
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            /* do the pass 1 butterfly */
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            r[0] = _mm_add_ps(a, b);
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            r[1] = _mm_sub_ps(a, b);
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            r += 2;
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        } while (--j != 0);
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    }
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    /* pass 2 .. ln-1 */
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    nblocks = np >> 3;
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    nloops = 1 << 2;
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    np2 = np >> 1;
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    cptr1 = s->exptab1;
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    do {
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        p = z;
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        q = z + nloops;
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        j = nblocks;
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        do {
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            cptr = cptr1;
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            k = nloops >> 1;
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            do {
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                __m128 a, b, c, t1, t2;
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                a = *(__m128 *)p;
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                b = *(__m128 *)q;
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                /* complex mul */
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                c = *(__m128 *)cptr;
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                /*  cre*re cim*re */
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                t1 = _mm_mul_ps(c, 
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                                _mm_shuffle_ps(b, b, _MM_SHUFFLE(2, 2, 0, 0))); 
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                c = *(__m128 *)(cptr + 2);
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                /*  -cim*im cre*im */
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                t2 = _mm_mul_ps(c,
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                                _mm_shuffle_ps(b, b, _MM_SHUFFLE(3, 3, 1, 1))); 
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                b = _mm_add_ps(t1, t2);
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                /* butterfly */
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                *(__m128 *)p = _mm_add_ps(a, b);
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                *(__m128 *)q = _mm_sub_ps(a, b);
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                p += 2;
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                q += 2;
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                cptr += 4;
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            } while (--k);
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            p += nloops;
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            q += nloops;
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        } while (--j);
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        cptr1 += nloops * 2;
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        nblocks = nblocks >> 1;
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        nloops = nloops << 1;
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    } while (nblocks != 0);
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}
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#endif