123 lines
3.3 KiB
C
123 lines
3.3 KiB
C
/* dvdisaster: Additional error correction for optical media.
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* Copyright (C) 2004-2017 Carsten Gnoerlich.
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* Copyright (C) 2019-2021 The dvdisaster development team.
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*
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* Email: support@dvdisaster.org
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*
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* This file is part of dvdisaster.
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*
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* dvdisaster is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* dvdisaster 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
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with dvdisaster. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include "dvdisaster.h"
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#ifdef HAVE_ALTIVEC
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# include <altivec.h>
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#endif
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#include <signal.h>
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#include <setjmp.h>
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/***
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*** Reed-Solomon encoding using AltiVec intrinsics
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***
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*** Based on rs-encoder-altivec.c
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*** AltiVec version by michael.klein@puffin.lb.shuttle.de
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***/
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/* AltiVec version */
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#ifdef HAVE_ALTIVEC
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static volatile int AltiVecPresent;
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static jmp_buf jmpbuf;
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void sig_ill_handler(int sig)
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{
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AltiVecPresent = 0;
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siglongjmp(jmpbuf, 0);
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}
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int ProbeAltiVec(void)
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{
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sig_t old_handler;
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AltiVecPresent = 1;
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old_handler = signal(SIGILL, sig_ill_handler);
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if(!sigsetjmp(jmpbuf, 0))
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{
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vector unsigned char v;
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asm volatile("vor %0, %0, %0": "=v"(v));
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}
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signal(SIGILL, old_handler);
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return AltiVecPresent;
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}
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void encode_next_layer_altivec(ReedSolomonTables *rt, unsigned char *data, unsigned char *parity, guint64 layer_size, int shift)
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{ gint32 *gf_index_of = rt->gfTables->indexOf;
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gint32 *enc_alpha_to = rt->gfTables->encAlphaTo;
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gint32 *rs_gpoly = rt->gpoly;
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int nroots = rt->nroots;
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int nroots_aligned = (nroots+15)&~15;
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int nroots_full = nroots_aligned>>4;
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int i,j;
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for(i=0; i<layer_size; i++)
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{ int feedback = gf_index_of[data[i] ^ parity[shift]];
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int offset = nroots-shift-1;
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if(feedback != GF_ALPHA0) /* non-zero feedback term */
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{ guint8 *par_idx = (guint8*)parity;
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guint8 *e_lut = rt->bLut[feedback]+offset;
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vector unsigned char par, lut, out, msq, lsq, mask;
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/* Process lut in 128 bit steps */
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mask = vec_lvsl(0, e_lut);
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for(j=nroots_full; j; j--)
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{
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par = vec_ld(0, par_idx);
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msq = vec_ld(0, e_lut);
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lsq = vec_ld(15, e_lut);
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lut = vec_perm(msq, lsq, mask);
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out = vec_xor(par, lut);
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vec_st(out, 0, par_idx);
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par_idx += 16;
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e_lut += 16;
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}
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parity[shift] = enc_alpha_to[feedback + rs_gpoly[0]];
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}
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else /* zero feedback term */
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parity[shift] = 0;
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parity += nroots_aligned;
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}
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}
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#else /* don't have ALTIVEC */
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int ProbeAltiVec()
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{ return 0;
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}
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void encode_next_layer_altivec(ReedSolomonTables *rt, unsigned char *data, unsigned char *parity, guint64 layer_size, int shift)
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{
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Stop("Mega borkage - EncodeNextLayerAltiVec() stub called.\n");
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}
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#endif /* HAVE_ALTIVEC */
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