14e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi/* K=9 r=1/2 Viterbi decoder for MMX 24e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi * Copyright Feb 2004, Phil Karn, KA9Q 34e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi * May be used under the terms of the GNU Lesser General Public License (LGPL) 44e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi */ 54e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi#include <stdio.h> 64e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi#include <stdlib.h> 74e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi#include <memory.h> 84e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi#include <mmintrin.h> 94e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi#include "fec.h" 104e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi 114e213d510f437769f8a28578dd4f786fb7d16c4Bill Yitypedef union { char c[256]; __m64 v[32];} decision_t; 124e213d510f437769f8a28578dd4f786fb7d16c4Bill Yitypedef union { unsigned char c[256]; __m64 v[32];} metric_t; 134e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi 144e213d510f437769f8a28578dd4f786fb7d16c4Bill Yiunsigned char Mettab29_1[256][128] __attribute__ ((aligned(8))); 154e213d510f437769f8a28578dd4f786fb7d16c4Bill Yiunsigned char Mettab29_2[256][128] __attribute__ ((aligned(8))); 164e213d510f437769f8a28578dd4f786fb7d16c4Bill Yistatic int Init = 0; 174e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi 184e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi/* State info for instance of Viterbi decoder 194e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi * Don't change this without also changing references in mmxbfly29.s! 204e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi */ 214e213d510f437769f8a28578dd4f786fb7d16c4Bill Yistruct v29 { 224e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi metric_t metrics1; /* path metric buffer 1 */ 234e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi metric_t metrics2; /* path metric buffer 2 */ 244e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi decision_t *dp; /* Pointer to current decision */ 254e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi metric_t *old_metrics,*new_metrics; /* Pointers to path metrics, swapped on every bit */ 264e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi decision_t *decisions; /* Beginning of decisions for block */ 274e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi}; 284e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi 294e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi/* Create a new instance of a Viterbi decoder */ 304e213d510f437769f8a28578dd4f786fb7d16c4Bill Yivoid *create_viterbi29_mmx(int len){ 314e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi struct v29 *vp; 324e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi 334e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi if(Init == 0){ 344e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi int polys[2] = {V29POLYA,V29POLYB}; 354e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi 364e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi set_viterbi29_polynomial_mmx(polys); 374e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi } 384e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi if((vp = (struct v29 *)malloc(sizeof(struct v29))) == NULL) 394e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi return NULL; 404e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi 414e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi if((vp->decisions = (decision_t *)malloc((len+8)*sizeof(decision_t))) == NULL){ 424e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi free(vp); 434e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi return NULL; 444e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi } 454e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi init_viterbi29(vp,0); 464e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi return vp; 474e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi} 484e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi 494e213d510f437769f8a28578dd4f786fb7d16c4Bill Yivoid set_viterbi29_polynomial_mmx(int polys[2]){ 504e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi int state; 514e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi 524e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi for(state=0;state < 128;state++){ 534e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi int symbol; 544e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi 554e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi for(symbol = 0;symbol < 256;symbol++){ 564e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi int sym; 574e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi 584e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi sym = parity((2*state) & abs(polys[0])) ^ (polys[0] < 0); 594e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi Mettab29_1[symbol][state] = (sym ? (255-symbol):symbol) / 16; 604e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi 614e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi sym = parity((2*state) & abs(polys[1])) ^ (polys[1] < 0); 624e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi Mettab29_2[symbol][state] = (sym ? (255-symbol):symbol) / 16; 634e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi } 644e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi } 654e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi Init++; 664e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi} 674e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi 684e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi/* Initialize Viterbi decoder for start of new frame */ 694e213d510f437769f8a28578dd4f786fb7d16c4Bill Yiint init_viterbi29_mmx(void *p,int starting_state){ 704e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi struct v29 *vp = p; 714e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi int i; 724e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi 734e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi if(p == NULL) 744e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi return -1; 754e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi for(i=0;i<256;i++) 764e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi vp->metrics1.c[i] = 63; 774e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi 784e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi vp->old_metrics = &vp->metrics1; 794e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi vp->new_metrics = &vp->metrics2; 804e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi vp->dp = vp->decisions; 814e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi vp->old_metrics->c[starting_state & 255] = 0; /* Bias known start state */ 824e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi return 0; 834e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi} 844e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi 854e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi/* Viterbi chainback */ 864e213d510f437769f8a28578dd4f786fb7d16c4Bill Yiint chainback_viterbi29_mmx( 874e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi void *p, 884e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi unsigned char *data, /* Decoded output data */ 894e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi unsigned int nbits, /* Number of data bits */ 904e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi unsigned int endstate){ /* Terminal encoder state */ 914e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi 924e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi struct v29 *vp = (struct v29 *)p; 934e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi decision_t *d; 944e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi 954e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi if(p == NULL) 964e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi return -1; 974e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi 984e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi d = (decision_t *)vp->decisions; 994e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi endstate &= 255; 1004e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi d += 8; /* Look past tail */ 1014e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi while(nbits-- != 0){ 1024e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi int k; 1034e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi 1044e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi k = d[nbits].c[endstate] & 1; 1054e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi data[nbits>>3] = endstate = (endstate >> 1) | (k << 7); 1064e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi } 1074e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi return 0; 1084e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi} 1094e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi 1104e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi/* Delete instance of a Viterbi decoder */ 1114e213d510f437769f8a28578dd4f786fb7d16c4Bill Yivoid delete_viterbi29_mmx(void *p){ 1124e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi struct v29 *vp = p; 1134e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi 1144e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi if(vp != NULL){ 1154e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi free(vp->decisions); 1164e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi free(vp); 1174e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi } 1184e213d510f437769f8a28578dd4f786fb7d16c4Bill Yi} 119