diff options
Diffstat (limited to 'gnuradio-core/src/lib/viterbi/viterbi.c')
| -rw-r--r-- | gnuradio-core/src/lib/viterbi/viterbi.c | 56 |
1 files changed, 28 insertions, 28 deletions
diff --git a/gnuradio-core/src/lib/viterbi/viterbi.c b/gnuradio-core/src/lib/viterbi/viterbi.c index 9f5c1e72a9..fc88866035 100644 --- a/gnuradio-core/src/lib/viterbi/viterbi.c +++ b/gnuradio-core/src/lib/viterbi/viterbi.c @@ -1,26 +1,26 @@ /* * Copyright 1995 Phil Karn, KA9Q * Copyright 2008 Free Software Foundation, Inc. - * + * * This file is part of GNU Radio - * + * * GNU Radio is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 3, or (at your option) * any later version. - * + * * GNU Radio 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 General Public License for more details. - * + * * You should have received a copy of the GNU General Public License * along with GNU Radio; see the file COPYING. If not, write to * the Free Software Foundation, Inc., 51 Franklin Street, * Boston, MA 02110-1301, USA. */ -/* +/* * Viterbi decoder for K=7 rate=1/2 convolutional code * Some modifications from original Karn code by Matt Ettus */ @@ -94,7 +94,7 @@ encode(unsigned char *symbols, unsigned char encstate) { int i; - + while(nbytes-- != 0){ for(i=7;i>=0;i--){ encstate = (encstate << 1) | ((*data >> i) & 1); @@ -103,7 +103,7 @@ encode(unsigned char *symbols, } data++; } - + return encstate; } @@ -120,16 +120,16 @@ viterbi(unsigned long *metric, /* Final path metric (returned value) */ long bestmetric; int beststate,i; struct viterbi_state state0[64],state1[64],*state,*next; - + state = state0; next = state1; - + /* Initialize starting metrics to prefer 0 state */ state[0].metric = 0; for(i=1;i<64;i++) state[i].metric = -999999; state[0].path = 0; - + for(bitcnt = 0;bitcnt < nbits;bitcnt++){ /* Read input symbol pair and compute all possible branch * metrics @@ -173,7 +173,7 @@ viterbi(unsigned long *metric, /* Final path metric (returned value) */ BUTTERFLY(29,0); BUTTERFLY(30,2); BUTTERFLY(31,3); - + /* Swap current and next states */ if(bitcnt & 1){ state = state0; @@ -205,7 +205,7 @@ viterbi(unsigned long *metric, /* Final path metric (returned value) */ #endif *data++ = state[beststate].path >> 24; } - + } /* Output remaining bits from 0 state */ // ETTUS Find best state instead @@ -219,7 +219,7 @@ viterbi(unsigned long *metric, /* Final path metric (returned value) */ } if((i = bitcnt % 8) != 6) state[beststate].path <<= 6-i; - + *data++ = state[beststate].path >> 24; *data++ = state[beststate].path >> 16; *data++ = state[beststate].path >> 8; @@ -245,7 +245,7 @@ viterbi_butterfly8(unsigned char *symbols, int mettab[2][256], struct viterbi_st { unsigned int bitcnt; int mets[4]; - + struct viterbi_state *state, *next; state = state0; next = state1; @@ -257,8 +257,8 @@ viterbi_butterfly8(unsigned char *symbols, int mettab[2][256], struct viterbi_st mets[2] = mettab[1][symbols[0]] + mettab[0][symbols[1]]; mets[3] = mettab[1][symbols[0]] + mettab[1][symbols[1]]; symbols += 2; - - // These macro calls were generated by genbut.c + + // These macro calls were generated by genbut.c BUTTERFLY(0,0);BUTTERFLY(1,1);BUTTERFLY(2,3);BUTTERFLY(3,2); BUTTERFLY(4,3);BUTTERFLY(5,2);BUTTERFLY(6,0);BUTTERFLY(7,1); BUTTERFLY(8,0);BUTTERFLY(9,1);BUTTERFLY(10,3);BUTTERFLY(11,2); @@ -267,7 +267,7 @@ viterbi_butterfly8(unsigned char *symbols, int mettab[2][256], struct viterbi_st BUTTERFLY(20,1);BUTTERFLY(21,0);BUTTERFLY(22,2);BUTTERFLY(23,3); BUTTERFLY(24,2);BUTTERFLY(25,3);BUTTERFLY(26,1);BUTTERFLY(27,0); BUTTERFLY(28,1);BUTTERFLY(29,0);BUTTERFLY(30,2);BUTTERFLY(31,3); - + // Swap current and next states if(bitcnt & 1){ state = state0; @@ -284,19 +284,19 @@ viterbi_butterfly2(unsigned char *symbols, int mettab[2][256], struct viterbi_st { //unsigned int bitcnt; int mets[4]; - + struct viterbi_state *state, *next; state = state0; next = state1; // Operate on 4 symbols (2 bits) at a time - + // Read input symbol pair and compute all possible branch metrics mets[0] = mettab[0][symbols[0]] + mettab[0][symbols[1]]; mets[1] = mettab[0][symbols[0]] + mettab[1][symbols[1]]; mets[2] = mettab[1][symbols[0]] + mettab[0][symbols[1]]; mets[3] = mettab[1][symbols[0]] + mettab[1][symbols[1]]; - - // These macro calls were generated by genbut.c + + // These macro calls were generated by genbut.c BUTTERFLY(0,0);BUTTERFLY(1,1);BUTTERFLY(2,3);BUTTERFLY(3,2); BUTTERFLY(4,3);BUTTERFLY(5,2);BUTTERFLY(6,0);BUTTERFLY(7,1); BUTTERFLY(8,0);BUTTERFLY(9,1);BUTTERFLY(10,3);BUTTERFLY(11,2); @@ -305,17 +305,17 @@ viterbi_butterfly2(unsigned char *symbols, int mettab[2][256], struct viterbi_st BUTTERFLY(20,1);BUTTERFLY(21,0);BUTTERFLY(22,2);BUTTERFLY(23,3); BUTTERFLY(24,2);BUTTERFLY(25,3);BUTTERFLY(26,1);BUTTERFLY(27,0); BUTTERFLY(28,1);BUTTERFLY(29,0);BUTTERFLY(30,2);BUTTERFLY(31,3); - + state = state1; next = state0; - + // Read input symbol pair and compute all possible branch metrics mets[0] = mettab[0][symbols[2]] + mettab[0][symbols[3]]; mets[1] = mettab[0][symbols[2]] + mettab[1][symbols[3]]; mets[2] = mettab[1][symbols[2]] + mettab[0][symbols[3]]; mets[3] = mettab[1][symbols[2]] + mettab[1][symbols[3]]; - - // These macro calls were generated by genbut.c + + // These macro calls were generated by genbut.c BUTTERFLY(0,0);BUTTERFLY(1,1);BUTTERFLY(2,3);BUTTERFLY(3,2); BUTTERFLY(4,3);BUTTERFLY(5,2);BUTTERFLY(6,0);BUTTERFLY(7,1); BUTTERFLY(8,0);BUTTERFLY(9,1);BUTTERFLY(10,3);BUTTERFLY(11,2); @@ -328,13 +328,13 @@ viterbi_butterfly2(unsigned char *symbols, int mettab[2][256], struct viterbi_st unsigned char viterbi_get_output(struct viterbi_state *state, unsigned char *outbuf) { - // Produce output every 8 bits once path memory is full + // Produce output every 8 bits once path memory is full // if((bitcnt % 8) == 5 && bitcnt > 32) { - + // Find current best path unsigned int i,beststate; int bestmetric; - + bestmetric = state[0].metric; beststate = 0; for(i=1;i<64;i++) |