/*
* 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 "config.h"
#include "libavutil/cpu.h"
#include "libavutil/ppc/cpu.h"
#include "libavutil/ppc/types_altivec.h"
#include "libavutil/ppc/util_altivec.h"
#include "libavcodec/fft.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 pairs of floats.
*/
#if HAVE_VSX
#include "fft_vsx.h"
#else
void ff_fft_calc_altivec(FFTContext *s, FFTComplex *z);
void ff_fft_calc_interleave_altivec(FFTContext *s, FFTComplex *z);
#endif
#if HAVE_GNU_AS && HAVE_ALTIVEC
static void 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);
#if HAVE_VSX
ff_fft_calc_vsx(s, (FFTComplex*)output);
#else
ff_fft_calc_altivec(s, (FFTComplex*)output);
#endif
/* post rotation + reordering */
j = -n32;
k = n32-1;
do {
#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 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 = {1U<<31,1U<<31,1U<<31,1U<<31};
vec_u32 *p0 = (vec_u32*)(output+n4);
vec_u32 *p1 = (vec_u32*)(output+n4*3);
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 && HAVE_ALTIVEC */
av_cold void ff_fft_init_ppc(FFTContext *s)
{
#if HAVE_GNU_AS && HAVE_ALTIVEC
if (!PPC_ALTIVEC(av_get_cpu_flags()))
return;
#if HAVE_VSX
s->fft_calc = ff_fft_calc_interleave_vsx;
#else
s->fft_calc = ff_fft_calc_interleave_altivec;
#endif
if (s->mdct_bits >= 5) {
s->imdct_calc = imdct_calc_altivec;
s->imdct_half = imdct_half_altivec;
}
#endif /* HAVE_GNU_AS && HAVE_ALTIVEC */
}