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  1. /*
  2.  * FFT/IFFT transforms
  3.  * AltiVec-enabled
  4.  * Copyright (c) 2009 Loren Merritt
  5.  *
  6.  * This file is part of FFmpeg.
  7.  *
  8.  * FFmpeg is free software; you can redistribute it and/or
  9.  * modify it under the terms of the GNU Lesser General Public
  10.  * License as published by the Free Software Foundation; either
  11.  * version 2.1 of the License, or (at your option) any later version.
  12.  *
  13.  * FFmpeg is distributed in the hope that it will be useful,
  14.  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15.  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16.  * Lesser General Public License for more details.
  17.  *
  18.  * You should have received a copy of the GNU Lesser General Public
  19.  * License along with FFmpeg; if not, write to the Free Software
  20.  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  21.  */
  22.  
  23. #include "config.h"
  24. #include "libavutil/cpu.h"
  25. #include "libavutil/ppc/types_altivec.h"
  26. #include "libavutil/ppc/util_altivec.h"
  27. #include "libavcodec/fft.h"
  28.  
  29. /**
  30.  * Do a complex FFT with the parameters defined in ff_fft_init(). The
  31.  * input data must be permuted before with s->revtab table. No
  32.  * 1.0/sqrt(n) normalization is done.
  33.  * AltiVec-enabled
  34.  * This code assumes that the 'z' pointer is 16 bytes-aligned
  35.  * It also assumes all FFTComplex are 8 bytes-aligned pair of float
  36.  */
  37.  
  38. void ff_fft_calc_altivec(FFTContext *s, FFTComplex *z);
  39. void ff_fft_calc_interleave_altivec(FFTContext *s, FFTComplex *z);
  40.  
  41. #if HAVE_GNU_AS && HAVE_ALTIVEC
  42. static void imdct_half_altivec(FFTContext *s, FFTSample *output, const FFTSample *input)
  43. {
  44.     int j, k;
  45.     int n = 1 << s->mdct_bits;
  46.     int n4 = n >> 2;
  47.     int n8 = n >> 3;
  48.     int n32 = n >> 5;
  49.     const uint16_t *revtabj = s->revtab;
  50.     const uint16_t *revtabk = s->revtab+n4;
  51.     const vec_f *tcos = (const vec_f*)(s->tcos+n8);
  52.     const vec_f *tsin = (const vec_f*)(s->tsin+n8);
  53.     const vec_f *pin = (const vec_f*)(input+n4);
  54.     vec_f *pout = (vec_f*)(output+n4);
  55.  
  56.     /* pre rotation */
  57.     k = n32-1;
  58.     do {
  59.         vec_f cos,sin,cos0,sin0,cos1,sin1,re,im,r0,i0,r1,i1,a,b,c,d;
  60. #define CMULA(p,o0,o1,o2,o3)\
  61.         a = pin[ k*2+p];                       /* { z[k].re,    z[k].im,    z[k+1].re,  z[k+1].im  } */\
  62.         b = pin[-k*2-p-1];                     /* { z[-k-2].re, z[-k-2].im, z[-k-1].re, z[-k-1].im } */\
  63.         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 } */\
  64.         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    } */\
  65.         cos = vec_perm(cos0, cos1, vcprm(o0,o1,s##o2,s##o3)); /* { cos[k], cos[k+1], cos[-k-2], cos[-k-1] } */\
  66.         sin = vec_perm(sin0, sin1, vcprm(o0,o1,s##o2,s##o3));\
  67.         r##p = im*cos - re*sin;\
  68.         i##p = re*cos + im*sin;
  69. #define STORE2(v,dst)\
  70.         j = dst;\
  71.         vec_ste(v, 0, output+j*2);\
  72.         vec_ste(v, 4, output+j*2);
  73. #define STORE8(p)\
  74.         a = vec_perm(r##p, i##p, vcprm(0,s0,0,s0));\
  75.         b = vec_perm(r##p, i##p, vcprm(1,s1,1,s1));\
  76.         c = vec_perm(r##p, i##p, vcprm(2,s2,2,s2));\
  77.         d = vec_perm(r##p, i##p, vcprm(3,s3,3,s3));\
  78.         STORE2(a, revtabk[ p*2-4]);\
  79.         STORE2(b, revtabk[ p*2-3]);\
  80.         STORE2(c, revtabj[-p*2+2]);\
  81.         STORE2(d, revtabj[-p*2+3]);
  82.  
  83.         cos0 = tcos[k];
  84.         sin0 = tsin[k];
  85.         cos1 = tcos[-k-1];
  86.         sin1 = tsin[-k-1];
  87.         CMULA(0, 0,1,2,3);
  88.         CMULA(1, 2,3,0,1);
  89.         STORE8(0);
  90.         STORE8(1);
  91.         revtabj += 4;
  92.         revtabk -= 4;
  93.         k--;
  94.     } while(k >= 0);
  95.  
  96.     ff_fft_calc_altivec(s, (FFTComplex*)output);
  97.  
  98.     /* post rotation + reordering */
  99.     j = -n32;
  100.     k = n32-1;
  101.     do {
  102.         vec_f cos,sin,re,im,a,b,c,d;
  103. #define CMULB(d0,d1,o)\
  104.         re = pout[o*2];\
  105.         im = pout[o*2+1];\
  106.         cos = tcos[o];\
  107.         sin = tsin[o];\
  108.         d0 = im*sin - re*cos;\
  109.         d1 = re*sin + im*cos;
  110.  
  111.         CMULB(a,b,j);
  112.         CMULB(c,d,k);
  113.         pout[2*j]   = vec_perm(a, d, vcprm(0,s3,1,s2));
  114.         pout[2*j+1] = vec_perm(a, d, vcprm(2,s1,3,s0));
  115.         pout[2*k]   = vec_perm(c, b, vcprm(0,s3,1,s2));
  116.         pout[2*k+1] = vec_perm(c, b, vcprm(2,s1,3,s0));
  117.         j++;
  118.         k--;
  119.     } while(k >= 0);
  120. }
  121.  
  122. static void imdct_calc_altivec(FFTContext *s, FFTSample *output, const FFTSample *input)
  123. {
  124.     int k;
  125.     int n = 1 << s->mdct_bits;
  126.     int n4 = n >> 2;
  127.     int n16 = n >> 4;
  128.     vec_u32 sign = {1U<<31,1U<<31,1U<<31,1U<<31};
  129.     vec_u32 *p0 = (vec_u32*)(output+n4);
  130.     vec_u32 *p1 = (vec_u32*)(output+n4*3);
  131.  
  132.     imdct_half_altivec(s, output + n4, input);
  133.  
  134.     for (k = 0; k < n16; k++) {
  135.         vec_u32 a = p0[k] ^ sign;
  136.         vec_u32 b = p1[-k-1];
  137.         p0[-k-1] = vec_perm(a, a, vcprm(3,2,1,0));
  138.         p1[k]    = vec_perm(b, b, vcprm(3,2,1,0));
  139.     }
  140. }
  141. #endif /* HAVE_GNU_AS && HAVE_ALTIVEC */
  142.  
  143. av_cold void ff_fft_init_ppc(FFTContext *s)
  144. {
  145. #if HAVE_GNU_AS && HAVE_ALTIVEC
  146.     if (!(av_get_cpu_flags() & AV_CPU_FLAG_ALTIVEC))
  147.         return;
  148.  
  149.     s->fft_calc   = ff_fft_calc_interleave_altivec;
  150.     if (s->mdct_bits >= 5) {
  151.         s->imdct_calc = imdct_calc_altivec;
  152.         s->imdct_half = imdct_half_altivec;
  153.     }
  154. #endif /* HAVE_GNU_AS && HAVE_ALTIVEC */
  155. }
  156.