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135 lines
3.9 KiB
135 lines
3.9 KiB
/* |
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* FFT/IFFT transforms |
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* AltiVec-enabled |
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* Copyright (c) 2003 Romain Dolbeau <romain@dolbeau.org> |
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* Based on code Copyright (c) 2002 Fabrice Bellard |
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* |
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* This file is part of FFmpeg. |
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* |
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* FFmpeg 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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* FFmpeg 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 FFmpeg; 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/dsputil.h" |
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#include "dsputil_ppc.h" |
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#include "util_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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* The code is exactly the same as the SSE version, except |
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* that successive MUL + ADD/SUB have been merged into |
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* fused multiply-add ('vec_madd' in altivec) |
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*/ |
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void ff_fft_calc_altivec(FFTContext *s, FFTComplex *z) |
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{ |
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POWERPC_PERF_DECLARE(altivec_fft_num, s->nbits >= 6); |
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register const vector float vczero = (const vector float)vec_splat_u32(0.); |
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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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POWERPC_PERF_START_COUNT(altivec_fft_num, s->nbits >= 6); |
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np = 1 << ln; |
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{ |
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vector float *r, a, b, a1, c1, c2; |
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r = (vector float *)&z[0]; |
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c1 = vcii(p,p,n,n); |
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if (s->inverse) { |
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c2 = vcii(p,p,n,p); |
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} else { |
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c2 = vcii(p,p,p,n); |
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} |
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j = (np >> 2); |
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do { |
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a = vec_ld(0, r); |
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a1 = vec_ld(sizeof(vector float), r); |
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b = vec_perm(a,a,vcprmle(1,0,3,2)); |
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a = vec_madd(a,c1,b); |
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/* do the pass 0 butterfly */ |
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b = vec_perm(a1,a1,vcprmle(1,0,3,2)); |
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b = vec_madd(a1,c1,b); |
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/* do the pass 0 butterfly */ |
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/* multiply third by -i */ |
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b = vec_perm(b,b,vcprmle(2,3,1,0)); |
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/* do the pass 1 butterfly */ |
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vec_st(vec_madd(b,c2,a), 0, r); |
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vec_st(vec_nmsub(b,c2,a), sizeof(vector float), r); |
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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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vector float a,b,c,t1; |
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a = vec_ld(0, (float*)p); |
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b = vec_ld(0, (float*)q); |
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/* complex mul */ |
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c = vec_ld(0, (float*)cptr); |
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/* cre*re cim*re */ |
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t1 = vec_madd(c, vec_perm(b,b,vcprmle(2,2,0,0)),vczero); |
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c = vec_ld(sizeof(vector float), (float*)cptr); |
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/* -cim*im cre*im */ |
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b = vec_madd(c, vec_perm(b,b,vcprmle(3,3,1,1)),t1); |
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/* butterfly */ |
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vec_st(vec_add(a,b), 0, (float*)p); |
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vec_st(vec_sub(a,b), 0, (float*)q); |
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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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POWERPC_PERF_STOP_COUNT(altivec_fft_num, s->nbits >= 6); |
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}
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