mirror of https://github.com/wb2osz/direwolf.git
Starting to look like a real project.
This commit is contained in:
David E. Tiller
parent
07209b5f22
commit
fa49b6a40b
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@ -280,6 +280,9 @@ int main (int argc, char *argv[])
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else if (strcasecmp(optarg, "EAS") == 0) {
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B_opt = 23456; // See special case below.
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}
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else if (strcasecmp(optarg, "EOTD") == 0) {
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B_opt = 34567;
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}
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else {
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B_opt = atoi(optarg);
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}
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@ -475,6 +478,12 @@ int main (int argc, char *argv[])
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my_audio_config.achan[0].space_freq = 1563; // Actually 1562.5 - logic 0.
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strlcpy (my_audio_config.achan[0].profiles, "D", sizeof(my_audio_config.achan[0].profiles));
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}
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else if (my_audio_config.achan[0].baud == 34567) {
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my_audio_config.achan[0].modem_type = MODEM_EOTD;
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my_audio_config.achan[0].baud = 1200;
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my_audio_config.achan[0].mark_freq = 1200;
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my_audio_config.achan[0].space_freq = 1800;
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}
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else {
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my_audio_config.achan[0].modem_type = MODEM_SCRAMBLE;
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my_audio_config.achan[0].mark_freq = 0;
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@ -1,3 +1,7 @@
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/* BCH processing, library-style. Copyright (2022) David E. Tiller, K4DET
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This file was adapted from a program written by Robert Morelos-Zaragoza
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(robert@spectra.eng.hawaii.edu) whose original Copyright appears below.
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*/
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/*
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* File: bch3.c
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* Title: Encoder/decoder for binary BCH codes in C (Version 3.1)
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@ -147,7 +151,7 @@ int init_bch(bch_t *bch, int m, int length, int t) {
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*
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* alpha=2 is the primitive element of GF(2**m)
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*/
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register int i, mask;
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register int mask;
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bch->alpha_to = malloc(n * sizeof(int));
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bch->index_of = malloc(n * sizeof(int));
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@ -339,7 +343,7 @@ int apply_bch(const bch_t *bch, int *recd)
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{
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register int i, j, u, q, t2, count = 0, syn_error = 0;
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int elp[1026][1024], d[1026], l[1026], u_lu[1026], s[1025];
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int root[200], loc[200], err[1024], reg[201];
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int root[200], loc[200], reg[201];
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t2 = 2 * bch->t;
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620
src/bch3a.c
620
src/bch3a.c
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@ -1,620 +0,0 @@
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/*
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* File: bch3.c
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* Title: Encoder/decoder for binary BCH codes in C (Version 3.1)
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* Author: Robert Morelos-Zaragoza
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* Date: August 1994
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* Revised: June 13, 1997
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*
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* =============== Encoder/Decoder for binary BCH codes in C =================
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*
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* Version 1: Original program. The user provides the generator polynomial
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* of the code (cumbersome!).
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* Version 2: Computes the generator polynomial of the code.
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* Version 3: No need to input the coefficients of a primitive polynomial of
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* degree m, used to construct the Galois Field GF(2**m). The
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* program now works for any binary BCH code of length such that:
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* 2**(m-1) - 1 < length <= 2**m - 1
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*
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* Note: You may have to change the size of the arrays to make it work.
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*
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* The encoding and decoding methods used in this program are based on the
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* book "Error Control Coding: Fundamentals and Applications", by Lin and
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* Costello, Prentice Hall, 1983.
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*
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* Thanks to Patrick Boyle (pboyle@era.com) for his observation that 'bch2.c'
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* did not work for lengths other than 2**m-1 which led to this new version.
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* Portions of this program are from 'rs.c', a Reed-Solomon encoder/decoder
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* in C, written by Simon Rockliff (simon@augean.ua.oz.au) on 21/9/89. The
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* previous version of the BCH encoder/decoder in C, 'bch2.c', was written by
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* Robert Morelos-Zaragoza (robert@spectra.eng.hawaii.edu) on 5/19/92.
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*
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* NOTE:
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* The author is not responsible for any malfunctioning of
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* this program, nor for any damage caused by it. Please include the
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* original program along with these comments in any redistribution.
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*
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* For more information, suggestions, or other ideas on implementing error
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* correcting codes, please contact me at:
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*
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* Robert Morelos-Zaragoza
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* 5120 Woodway, Suite 7036
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* Houston, Texas 77056
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*
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* email: r.morelos-zaragoza@ieee.org
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*
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* COPYRIGHT NOTICE: This computer program is free for non-commercial purposes.
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* You may implement this program for any non-commercial application. You may
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* also implement this program for commercial purposes, provided that you
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* obtain my written permission. Any modification of this program is covered
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* by this copyright.
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*
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* == Copyright (c) 1994-7, Robert Morelos-Zaragoza. All rights reserved. ==
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*
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* m = order of the Galois field GF(2**m)
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* n = 2**m - 1 = size of the multiplicative group of GF(2**m)
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* length = length of the BCH code
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* t = error correcting capability (max. no. of errors the code corrects)
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* d = 2*t + 1 = designed min. distance = no. of consecutive roots of g(x) + 1
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* k = n - deg(g(x)) = dimension (no. of information bits/codeword) of the code
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* p[] = coefficients of a primitive polynomial used to generate GF(2**m)
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* g[] = coefficients of the generator polynomial, g(x)
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* alpha_to [] = log table of GF(2**m)
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* index_of[] = antilog table of GF(2**m)
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* data[] = information bits = coefficients of data polynomial, i(x)
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* bb[] = coefficients of redundancy polynomial x^(length-k) i(x) modulo g(x)
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* numerr = number of errors
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* errpos[] = error positions
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* recd[] = coefficients of the received polynomial
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* decerror = number of decoding errors (in _message_ positions)
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*
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*/
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#include <math.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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int m, n, length, k, t, d;
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int p[21];
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int alpha_to[1048576], index_of[1048576], g[548576];
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int recd[1048576], data[1048576], bb[548576];
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int seed;
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int numerr, errpos[1024], decerror = 0;
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int orig_recd[1048576];
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uint64_t packets[] = {
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#define ALL_DATA
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/* GOOD TEST */ 0xb217a2b953ddc552, /* random example from bch3 program */
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#ifdef ALL_DATA
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0xf05a6a6a016333d0, /* g001-cut-lenthened_457.938M.wav */
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0xf081526b71a56308, /* 1st in eotd_received_data */
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/* 3 errors */ 0xf085506a01e56e84, /* 2nd in eotd_received_data */
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/* fixed */ 0xf085506a01e50684, /* 2nd, but with the bits fixed */
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#endif
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#ifdef ALL_DATA
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0xf085595a01e56e84, /* 3rd */
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0xf134501a01e566fe, /* 4th */
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0xf0eb10ea016e541c, /* 5th */
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0xf0ea5cea016e550e, /* 6th */
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0xe021101a0132bce4, /* Sun Mar 20 05:41:00 2022 */
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0xf042505bcfd564e4, /* Sun Mar 20 12:58:43 2022 */
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0xf08c10aa01737b1a, /* Sun Mar 20 13:35:48 2022 */
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0xf08c10b1c0e09064, /* Sun Mar 20 13:37:05 2022 */
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0xf08c106a01647ae8, /* Sun Mar 20 13:37:48 2022 */
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0x508c126a01647ae8,
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#endif
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};
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void
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read_p()
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/*
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* Read m, the degree of a primitive polynomial p(x) used to compute the
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* Galois field GF(2**m). Get precomputed coefficients p[] of p(x). Read
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* the code length.
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*/
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{
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int i, ninf;
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printf("bch3: An encoder/decoder for binary BCH codes\n");
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printf("Copyright (c) 1994-7. Robert Morelos-Zaragoza.\n");
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printf("This program is free, please read first the copyright notice.\n");
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printf("\nFirst, enter a value of m such that the code length is\n");
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printf("2**(m-1) - 1 < length <= 2**m - 1\n\n");
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do {
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//printf("Enter m (between 2 and 20): ");
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//scanf("%d", &m);
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m = 6;
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} while ( !(m>1) || !(m<21) );
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for (i=1; i<m; i++)
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p[i] = 0;
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p[0] = p[m] = 1;
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if (m == 2) p[1] = 1;
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else if (m == 3) p[1] = 1;
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else if (m == 4) p[1] = 1;
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else if (m == 5) p[2] = 1;
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else if (m == 6) p[1] = 1;
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else if (m == 7) p[1] = 1;
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else if (m == 8) p[4] = p[5] = p[6] = 1;
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else if (m == 9) p[4] = 1;
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else if (m == 10) p[3] = 1;
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else if (m == 11) p[2] = 1;
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else if (m == 12) p[3] = p[4] = p[7] = 1;
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else if (m == 13) p[1] = p[3] = p[4] = 1;
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else if (m == 14) p[1] = p[11] = p[12] = 1;
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else if (m == 15) p[1] = 1;
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else if (m == 16) p[2] = p[3] = p[5] = 1;
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else if (m == 17) p[3] = 1;
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else if (m == 18) p[7] = 1;
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else if (m == 19) p[1] = p[5] = p[6] = 1;
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else if (m == 20) p[3] = 1;
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printf("p(x) = ");
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n = 1;
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for (i = 0; i <= m; i++) {
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n *= 2;
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printf("%1d", p[i]);
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}
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printf("\n");
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n = n / 2 - 1;
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ninf = (n + 1) / 2 - 1;
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/* do {
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printf("Enter code length (%d < length <= %d): ", ninf, n);
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scanf("%d", &length);
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} while ( !((length <= n)&&(length>ninf)) ); */
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length = 63;
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}
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void
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generate_gf()
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/*
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* Generate field GF(2**m) from the irreducible polynomial p(X) with
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* coefficients in p[0]..p[m].
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*
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* Lookup tables:
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* index->polynomial form: alpha_to[] contains j=alpha^i;
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* polynomial form -> index form: index_of[j=alpha^i] = i
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*
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* alpha=2 is the primitive element of GF(2**m)
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*/
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{
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register int i, mask;
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mask = 1;
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alpha_to[m] = 0;
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for (i = 0; i < m; i++) {
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alpha_to[i] = mask;
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index_of[alpha_to[i]] = i;
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if (p[i] != 0)
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alpha_to[m] ^= mask;
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mask <<= 1;
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}
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index_of[alpha_to[m]] = m;
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mask >>= 1;
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for (i = m + 1; i < n; i++) {
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if (alpha_to[i - 1] >= mask)
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alpha_to[i] = alpha_to[m] ^ ((alpha_to[i - 1] ^ mask) << 1);
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else
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alpha_to[i] = alpha_to[i - 1] << 1;
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index_of[alpha_to[i]] = i;
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}
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index_of[0] = -1;
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}
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void
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gen_poly()
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/*
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* Compute the generator polynomial of a binary BCH code. Fist generate the
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* cycle sets modulo 2**m - 1, cycle[][] = (i, 2*i, 4*i, ..., 2^l*i). Then
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* determine those cycle sets that contain integers in the set of (d-1)
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* consecutive integers {1..(d-1)}. The generator polynomial is calculated
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* as the product of linear factors of the form (x+alpha^i), for every i in
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* the above cycle sets.
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*/
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{
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register int ii, jj, ll, kaux;
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register int test, aux, nocycles, root, noterms, rdncy;
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int cycle[1024][21], size[1024], min[1024], zeros[1024];
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/* Generate cycle sets modulo n, n = 2**m - 1 */
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cycle[0][0] = 0;
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size[0] = 1;
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cycle[1][0] = 1;
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size[1] = 1;
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jj = 1; /* cycle set index */
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if (m > 9) {
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printf("Computing cycle sets modulo %d\n", n);
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printf("(This may take some time)...\n");
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}
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do {
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/* Generate the jj-th cycle set */
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ii = 0;
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do {
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ii++;
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cycle[jj][ii] = (cycle[jj][ii - 1] * 2) % n;
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size[jj]++;
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aux = (cycle[jj][ii] * 2) % n;
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} while (aux != cycle[jj][0]);
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/* Next cycle set representative */
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ll = 0;
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do {
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ll++;
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test = 0;
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for (ii = 1; ((ii <= jj) && (!test)); ii++)
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/* Examine previous cycle sets */
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for (kaux = 0; ((kaux < size[ii]) && (!test)); kaux++)
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if (ll == cycle[ii][kaux])
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test = 1;
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} while ((test) && (ll < (n - 1)));
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if (!(test)) {
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jj++; /* next cycle set index */
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cycle[jj][0] = ll;
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size[jj] = 1;
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}
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} while (ll < (n - 1));
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nocycles = jj; /* number of cycle sets modulo n */
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//printf("Enter the error correcting capability, t: ");
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//scanf("%d", &t);
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t =3;
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d = 2 * t + 1;
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/* Search for roots 1, 2, ..., d-1 in cycle sets */
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kaux = 0;
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rdncy = 0;
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for (ii = 1; ii <= nocycles; ii++) {
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min[kaux] = 0;
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test = 0;
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for (jj = 0; ((jj < size[ii]) && (!test)); jj++)
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for (root = 1; ((root < d) && (!test)); root++)
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if (root == cycle[ii][jj]) {
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test = 1;
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min[kaux] = ii;
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}
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if (min[kaux]) {
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rdncy += size[min[kaux]];
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kaux++;
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}
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}
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noterms = kaux;
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kaux = 1;
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for (ii = 0; ii < noterms; ii++)
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for (jj = 0; jj < size[min[ii]]; jj++) {
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zeros[kaux] = cycle[min[ii]][jj];
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kaux++;
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}
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k = length - rdncy;
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if (k<0)
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{
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printf("Parameters invalid!\n");
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exit(0);
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}
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printf("This is a (%d, %d, %d) binary BCH code\n", length, k, d);
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/* Compute the generator polynomial */
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g[0] = alpha_to[zeros[1]];
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g[1] = 1; /* g(x) = (X + zeros[1]) initially */
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for (ii = 2; ii <= rdncy; ii++) {
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g[ii] = 1;
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for (jj = ii - 1; jj > 0; jj--)
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if (g[jj] != 0)
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g[jj] = g[jj - 1] ^ alpha_to[(index_of[g[jj]] + zeros[ii]) % n];
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else
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g[jj] = g[jj - 1];
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g[0] = alpha_to[(index_of[g[0]] + zeros[ii]) % n];
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}
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printf("Generator polynomial:\ng(x) = ");
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for (ii = 0; ii <= rdncy; ii++) {
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printf("%d", g[ii]);
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}
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printf("\n");
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}
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void
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encode_bch()
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/*
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* Compute redundacy bb[], the coefficients of b(x). The redundancy
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* polynomial b(x) is the remainder after dividing x^(length-k)*data(x)
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* by the generator polynomial g(x).
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*/
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{
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register int i, j;
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register int feedback;
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for (i = 0; i < length - k; i++)
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bb[i] = 0;
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for (i = k - 1; i >= 0; i--) {
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feedback = data[i] ^ bb[length - k - 1];
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if (feedback != 0) {
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for (j = length - k - 1; j > 0; j--)
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if (g[j] != 0)
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bb[j] = bb[j - 1] ^ feedback;
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else
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bb[j] = bb[j - 1];
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bb[0] = g[0] && feedback;
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} else {
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for (j = length - k - 1; j > 0; j--)
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bb[j] = bb[j - 1];
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bb[0] = 0;
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}
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}
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}
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/* zero = success */
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int
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decode_bch()
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/*
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* Simon Rockliff's implementation of Berlekamp's algorithm.
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*
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* Assume we have received bits in recd[i], i=0..(n-1).
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*
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* Compute the 2*t syndromes by substituting alpha^i into rec(X) and
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* evaluating, storing the syndromes in s[i], i=1..2t (leave s[0] zero) .
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* Then we use the Berlekamp algorithm to find the error location polynomial
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* elp[i].
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*
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* If the degree of the elp is >t, then we cannot correct all the errors, and
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* we have detected an uncorrectable error pattern. We output the information
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* bits uncorrected.
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*
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* If the degree of elp is <=t, we substitute alpha^i , i=1..n into the elp
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* to get the roots, hence the inverse roots, the error location numbers.
|
||||
* This step is usually called "Chien's search".
|
||||
*
|
||||
* If the number of errors located is not equal the degree of the elp, then
|
||||
* the decoder assumes that there are more than t errors and cannot correct
|
||||
* them, only detect them. We output the information bits uncorrected.
|
||||
*/
|
||||
{
|
||||
register int i, j, u, q, t2, count = 0, syn_error = 0;
|
||||
int elp[1026][1024], d[1026], l[1026], u_lu[1026], s[1025];
|
||||
int root[200], loc[200], err[1024], reg[201];
|
||||
|
||||
t2 = 2 * t;
|
||||
|
||||
/* first form the syndromes */
|
||||
printf("S(x) = ");
|
||||
for (i = 1; i <= t2; i++) {
|
||||
s[i] = 0;
|
||||
for (j = 0; j < length; j++)
|
||||
if (recd[j] != 0)
|
||||
s[i] ^= alpha_to[(i * j) % n];
|
||||
if (s[i] != 0)
|
||||
syn_error = 1; /* set error flag if non-zero syndrome */
|
||||
/*
|
||||
* Note: If the code is used only for ERROR DETECTION, then
|
||||
* exit program here indicating the presence of errors.
|
||||
*/
|
||||
/* convert syndrome from polynomial form to index form */
|
||||
s[i] = index_of[s[i]];
|
||||
printf("%3d ", s[i]);
|
||||
}
|
||||
printf("\n");
|
||||
|
||||
if (syn_error) { /* if there are errors, try to correct them */
|
||||
/*
|
||||
* Compute the error location polynomial via the Berlekamp
|
||||
* iterative algorithm. Following the terminology of Lin and
|
||||
* Costello's book : d[u] is the 'mu'th discrepancy, where
|
||||
* u='mu'+1 and 'mu' (the Greek letter!) is the step number
|
||||
* ranging from -1 to 2*t (see L&C), l[u] is the degree of
|
||||
* the elp at that step, and u_l[u] is the difference between
|
||||
* the step number and the degree of the elp.
|
||||
*/
|
||||
/* initialise table entries */
|
||||
d[0] = 0; /* index form */
|
||||
d[1] = s[1]; /* index form */
|
||||
elp[0][0] = 0; /* index form */
|
||||
elp[1][0] = 1; /* polynomial form */
|
||||
for (i = 1; i < t2; i++) {
|
||||
elp[0][i] = -1; /* index form */
|
||||
elp[1][i] = 0; /* polynomial form */
|
||||
}
|
||||
l[0] = 0;
|
||||
l[1] = 0;
|
||||
u_lu[0] = -1;
|
||||
u_lu[1] = 0;
|
||||
u = 0;
|
||||
|
||||
do {
|
||||
u++;
|
||||
if (d[u] == -1) {
|
||||
l[u + 1] = l[u];
|
||||
for (i = 0; i <= l[u]; i++) {
|
||||
elp[u + 1][i] = elp[u][i];
|
||||
elp[u][i] = index_of[elp[u][i]];
|
||||
}
|
||||
} else
|
||||
/*
|
||||
* search for words with greatest u_lu[q] for
|
||||
* which d[q]!=0
|
||||
*/
|
||||
{
|
||||
q = u - 1;
|
||||
while ((d[q] == -1) && (q > 0))
|
||||
q--;
|
||||
/* have found first non-zero d[q] */
|
||||
if (q > 0) {
|
||||
j = q;
|
||||
do {
|
||||
j--;
|
||||
if ((d[j] != -1) && (u_lu[q] < u_lu[j]))
|
||||
q = j;
|
||||
} while (j > 0);
|
||||
}
|
||||
|
||||
/*
|
||||
* have now found q such that d[u]!=0 and
|
||||
* u_lu[q] is maximum
|
||||
*/
|
||||
/* store degree of new elp polynomial */
|
||||
if (l[u] > l[q] + u - q)
|
||||
l[u + 1] = l[u];
|
||||
else
|
||||
l[u + 1] = l[q] + u - q;
|
||||
|
||||
/* form new elp(x) */
|
||||
for (i = 0; i < t2; i++)
|
||||
elp[u + 1][i] = 0;
|
||||
for (i = 0; i <= l[q]; i++)
|
||||
if (elp[q][i] != -1)
|
||||
elp[u + 1][i + u - q] =
|
||||
alpha_to[(d[u] + n - d[q] + elp[q][i]) % n];
|
||||
for (i = 0; i <= l[u]; i++) {
|
||||
elp[u + 1][i] ^= elp[u][i];
|
||||
elp[u][i] = index_of[elp[u][i]];
|
||||
}
|
||||
}
|
||||
u_lu[u + 1] = u - l[u + 1];
|
||||
|
||||
/* form (u+1)th discrepancy */
|
||||
if (u < t2) {
|
||||
/* no discrepancy computed on last iteration */
|
||||
if (s[u + 1] != -1)
|
||||
d[u + 1] = alpha_to[s[u + 1]];
|
||||
else
|
||||
d[u + 1] = 0;
|
||||
for (i = 1; i <= l[u + 1]; i++)
|
||||
if ((s[u + 1 - i] != -1) && (elp[u + 1][i] != 0))
|
||||
d[u + 1] ^= alpha_to[(s[u + 1 - i]
|
||||
+ index_of[elp[u + 1][i]]) % n];
|
||||
/* put d[u+1] into index form */
|
||||
d[u + 1] = index_of[d[u + 1]];
|
||||
}
|
||||
} while ((u < t2) && (l[u + 1] <= t));
|
||||
|
||||
u++;
|
||||
if (l[u] <= t) {/* Can correct errors */
|
||||
/* put elp into index form */
|
||||
for (i = 0; i <= l[u]; i++)
|
||||
elp[u][i] = index_of[elp[u][i]];
|
||||
|
||||
printf("sigma(x) = ");
|
||||
for (i = 0; i <= l[u]; i++)
|
||||
printf("%3d ", elp[u][i]);
|
||||
printf("\n");
|
||||
printf("Roots: ");
|
||||
|
||||
/* Chien search: find roots of the error location polynomial */
|
||||
for (i = 1; i <= l[u]; i++)
|
||||
reg[i] = elp[u][i];
|
||||
count = 0;
|
||||
for (i = 1; i <= n; i++) {
|
||||
q = 1;
|
||||
for (j = 1; j <= l[u]; j++)
|
||||
if (reg[j] != -1) {
|
||||
reg[j] = (reg[j] + j) % n;
|
||||
q ^= alpha_to[reg[j]];
|
||||
}
|
||||
if (!q) { /* store root and error
|
||||
* location number indices */
|
||||
root[count] = i;
|
||||
loc[count] = n - i;
|
||||
count++;
|
||||
printf("%3d ", n - i);
|
||||
}
|
||||
}
|
||||
printf("\n");
|
||||
if (count == l[u])
|
||||
/* no. roots = degree of elp hence <= t errors */
|
||||
for (i = 0; i < l[u]; i++)
|
||||
recd[loc[i]] ^= 1;
|
||||
else { /* elp has degree >t hence cannot solve */
|
||||
printf("Incomplete decoding: errors detected\n");
|
||||
return 1;
|
||||
}
|
||||
}
|
||||
}
|
||||
return 0;
|
||||
}
|
||||
|
||||
void setup(int idx) {
|
||||
uint64_t pkt = packets[idx];
|
||||
printf("\n\nPACKET %llx\n", pkt);
|
||||
printf("-------------------------\n");
|
||||
pkt >>= 1; // Lose dummy bit */
|
||||
|
||||
/* Move BCH code over */
|
||||
for (int i = length - k - 1; i >= 0; i--) {
|
||||
recd[i] = pkt & 0x01;
|
||||
pkt >>= 1;
|
||||
}
|
||||
|
||||
/* Move data over */
|
||||
for (int i = length - 1; i >= length - k; i--) {
|
||||
recd[i] = pkt & 0x01;
|
||||
data[i - length + k] = recd[i];
|
||||
pkt >>= 1;
|
||||
}
|
||||
}
|
||||
|
||||
int main()
|
||||
{
|
||||
int i;
|
||||
|
||||
read_p(); /* Read m */
|
||||
generate_gf(); /* Construct the Galois Field GF(2**m) */
|
||||
gen_poly(); /* Compute the generator polynomial of BCH code */
|
||||
|
||||
for (int count = 0; count < sizeof(packets) / sizeof(uint64_t); count++) {
|
||||
setup(count);
|
||||
memcpy(&orig_recd, recd, sizeof(recd));
|
||||
|
||||
int result = decode_bch(); /* DECODE received codeword recd[] */
|
||||
|
||||
printf("n=%d, k=%d, length=%d\n", n, k, length);
|
||||
printf("Results:\n");
|
||||
printf("\noriginal pkt: ");
|
||||
for (int i = 0; i < length; i++) {
|
||||
if (i == length - k) printf(" ");
|
||||
printf("%d", orig_recd[i]);
|
||||
}
|
||||
printf("\n");
|
||||
|
||||
if (result) continue;
|
||||
/*
|
||||
* DECODING ERRORS? we compare only the data portion
|
||||
*/
|
||||
for (i = length - k; i < length; i++)
|
||||
if (data[i - length + k] != recd[i])
|
||||
decerror++;
|
||||
if (decerror) {
|
||||
printf("There were %d decoding errors in message positions\n", decerror);
|
||||
continue;
|
||||
}
|
||||
|
||||
/*
|
||||
* print out original and decoded data
|
||||
*/
|
||||
printf("recovered pkt: ");
|
||||
for (i = 0; i < length; i++) {
|
||||
if (i == length - k) printf(" ");
|
||||
printf("%1d", recd[i]);
|
||||
}
|
||||
printf("\n");
|
||||
|
||||
|
||||
int flag = 0;
|
||||
printf("------------ ");
|
||||
for (int jj = 0; jj < length; jj++) {
|
||||
if (jj == length - k) printf(" ");
|
||||
if (orig_recd[jj] != recd[jj]) {
|
||||
printf("^");
|
||||
//printf("bit %d: expected %d calc: %d\n", jj, orig_recd[jj], recd[jj]);
|
||||
flag++;
|
||||
} else {
|
||||
printf(" ");
|
||||
}
|
||||
}
|
||||
printf("\n%d ERRORS.\n", flag);
|
||||
|
||||
|
||||
}
|
||||
}
|
||||
|
|
@ -0,0 +1,176 @@
|
|||
#include <stdio.h>
|
||||
#include <string.h>
|
||||
#include "bch.h"
|
||||
|
||||
#define SHOW_BYTES
|
||||
|
||||
int test(bch_t *bch, char *msg, int *bits, int length) {
|
||||
int corrected = 0;
|
||||
int temp_bits[length];
|
||||
uint8_t bytes[8];
|
||||
|
||||
memcpy(temp_bits, bits, length * sizeof(int));
|
||||
#ifdef SHOW_BYTES
|
||||
bits_to_bytes(temp_bits, bytes, length);
|
||||
print_bytes(msg, bytes, 8);
|
||||
#else
|
||||
print_bits(msg, temp_bits, length);
|
||||
#endif
|
||||
corrected = apply_bch(bch, temp_bits);
|
||||
|
||||
if (corrected >= 0) {
|
||||
printf("corrected %d ", corrected);
|
||||
#ifdef SHOW_BYTES
|
||||
bits_to_bytes(temp_bits, bytes, length);
|
||||
printf("CORR ");
|
||||
print_bytes(msg, bytes, 8);
|
||||
#else
|
||||
print_bits(msg, temp_bits, length);
|
||||
#endif
|
||||
printf("\n");
|
||||
} else {
|
||||
printf("invalid.\n");
|
||||
}
|
||||
|
||||
return corrected >= 0;
|
||||
}
|
||||
|
||||
int main(int argc, char **argv) {
|
||||
bch_t bch;
|
||||
uint8_t bytes[8];
|
||||
int m, length, t;
|
||||
int data_len, crc_len;
|
||||
|
||||
|
||||
if (argc != 4) {
|
||||
fprintf(stderr, "Expecting 3 arguments.\n");
|
||||
return -1;
|
||||
}
|
||||
|
||||
sscanf(argv[1], "%d", &m);
|
||||
sscanf(argv[2], "%d", &length);
|
||||
sscanf(argv[3], "%d", &t);
|
||||
|
||||
int orig_bits[length+1];
|
||||
|
||||
init_bch(&bch, m, length, t);
|
||||
data_len = bch.k;
|
||||
crc_len = bch.length - bch.k;
|
||||
|
||||
printf("m=%d, length=%d, n=%d, k=%d, t=%d\n", bch.m, bch.length, bch.n, bch.k, bch.t);
|
||||
printf("data_len=%d, crc_len=%d\n", data_len, crc_len);
|
||||
|
||||
//
|
||||
// THIS IS THE LSB-FIRST VERSION
|
||||
//
|
||||
fprintf(stderr, "Enter HCB+ATAD _WITH_ the parity bit intact.\n");
|
||||
while (1) {
|
||||
for (int i = 0; i < 8; i++) {
|
||||
int temp;
|
||||
int status = scanf("%x ", &temp);
|
||||
bytes[i] = temp;
|
||||
if (status == EOF) {
|
||||
return 0;
|
||||
}
|
||||
|
||||
if (status != 1) {
|
||||
fprintf(stderr, "Error: %d", status);
|
||||
}
|
||||
printf("%0x ", bytes[i]);
|
||||
}
|
||||
printf("\n");
|
||||
|
||||
int temp[length];
|
||||
|
||||
// HCB + ATAD
|
||||
bytes_to_bits(bytes, orig_bits, length+1);
|
||||
memcpy(temp, orig_bits+1, length * sizeof(int));
|
||||
print_bits("atad: ", temp + crc_len, data_len);
|
||||
printf("\n");
|
||||
print_bits("hcb: ", temp, crc_len);
|
||||
printf("\n");
|
||||
|
||||
test(&bch, "HCB+ATAD: ", temp, length);
|
||||
|
||||
// ATAD+HCB
|
||||
bytes_to_bits(bytes, orig_bits, length+1);
|
||||
swap_format(orig_bits+1, temp, crc_len, length);
|
||||
print_bits("atad: ", temp, data_len);
|
||||
printf("\n");
|
||||
print_bits("hcb: ", temp+data_len, crc_len);
|
||||
printf("\n");
|
||||
test(&bch, "ATAD+HCB: ", temp, length);
|
||||
|
||||
// DATA + BCH
|
||||
bytes_to_bits(bytes, orig_bits, length+1);
|
||||
rotate_bits(orig_bits+1, temp, length);
|
||||
print_bits("data: ", temp, data_len);
|
||||
printf("\n");
|
||||
print_bits("bch: ", temp+data_len, crc_len);
|
||||
printf("\n");
|
||||
test(&bch, "DATA+BCH: ", temp, length);
|
||||
|
||||
// BCH+DATA
|
||||
int swap[length];
|
||||
bytes_to_bits(bytes, orig_bits, length+1);
|
||||
rotate_bits(orig_bits+1, temp, length);
|
||||
// now DATA+BCH
|
||||
swap_format(temp, swap, data_len, length);
|
||||
// now BCH + DATA
|
||||
print_bits("data: ", swap + crc_len, data_len);
|
||||
printf("\n");
|
||||
print_bits("bch: ", swap, crc_len);
|
||||
printf("\n");
|
||||
test(&bch, "BCH+DATA: ", swap, length);
|
||||
|
||||
int rot[length];
|
||||
// DATA + HCB
|
||||
bytes_to_bits(bytes, orig_bits, length+1);
|
||||
memcpy(rot+data_len, orig_bits + 1, crc_len * sizeof(int));
|
||||
rotate_bits(orig_bits+1+crc_len, temp, data_len);
|
||||
memcpy(rot, temp, data_len * sizeof(int));
|
||||
print_bits("data: ", rot, data_len);
|
||||
printf("\n");
|
||||
print_bits("hcb: ", rot+data_len, crc_len);
|
||||
printf("\n");
|
||||
// Now DATA+HCB
|
||||
test(&bch, "DATA+HCB: ", rot, length);
|
||||
|
||||
// ATAD+BCH
|
||||
bytes_to_bits(bytes, orig_bits, length+1);
|
||||
// h+a
|
||||
memcpy(rot, orig_bits+1+crc_len, data_len * sizeof(int));
|
||||
rotate_bits(orig_bits+1, temp, crc_len);
|
||||
memcpy(rot+data_len, temp, crc_len * sizeof(int));
|
||||
// Now ATAD+BCH
|
||||
print_bits("atad: ", rot, data_len);
|
||||
printf("\n");
|
||||
print_bits("bch: ", rot+data_len, crc_len);
|
||||
printf("\n");
|
||||
test(&bch, "ATAD+BCH: ", rot, length);
|
||||
|
||||
// HCB+DATA
|
||||
bytes_to_bits(bytes, orig_bits, length+1);
|
||||
memcpy(rot, orig_bits+1, crc_len * sizeof(int));
|
||||
rotate_bits(orig_bits+1+crc_len, temp, data_len);
|
||||
memcpy(rot+crc_len, temp, data_len * sizeof(int));
|
||||
print_bits("data: ", rot+crc_len, data_len);
|
||||
printf("\n");
|
||||
print_bits("hcb: ", rot, crc_len);
|
||||
printf("\n");
|
||||
// Now HCB+DATA
|
||||
test(&bch, "HCB+DATA: ", rot, length);
|
||||
|
||||
// BCH+ATAD
|
||||
bytes_to_bits(bytes, orig_bits, length+1);
|
||||
memcpy(rot+crc_len, orig_bits+1+crc_len, data_len * sizeof(int));
|
||||
rotate_bits(orig_bits+1, temp, crc_len);
|
||||
memcpy(rot, temp, crc_len * sizeof(int));
|
||||
print_bits("atad: ", rot + crc_len, data_len);
|
||||
printf("\n");
|
||||
print_bits("bch: ", rot, crc_len);
|
||||
printf("\n");
|
||||
// Now BCH+ATAD
|
||||
test(&bch, "BCH+ATAD: ", rot, length);
|
||||
}
|
||||
}
|
||||
|
|
@ -768,7 +768,6 @@ int main (int argc, char *argv[])
|
|||
audio_config.achan[0].baud = 1200;
|
||||
audio_config.achan[0].mark_freq = 1200;
|
||||
audio_config.achan[0].space_freq = 1800;
|
||||
// strlcpy (audio_config.achan[0].profiles, "D", sizeof(audio_config.achan[0].profiles));
|
||||
}
|
||||
else {
|
||||
audio_config.achan[0].modem_type = MODEM_SCRAMBLE;
|
||||
|
|
|
|||
|
|
@ -0,0 +1,14 @@
|
|||
#ifndef __EOTD_DEFS
|
||||
#define __EOTD_DEFS
|
||||
#define EOTD_LENGTH 8
|
||||
|
||||
#define EOTD_PREAMBLE_AND_BARKER_CODE 0x48eaaaaa00000000ULL
|
||||
#define EOTD_PREAMBLE_MASK 0xffffffff00000000ULL
|
||||
|
||||
#define HOTD_PREAMBLE_AND_BARKER_CODE 0x9488f1aa00000000ULL
|
||||
#define HOTD_PREAMBLE_MASK 0xffffffff00000000ULL
|
||||
|
||||
#define EOTD_TYPE_F2R 'F'
|
||||
#define EOTD_TYPE_R2F 'R'
|
||||
|
||||
#endif
|
||||
|
|
@ -55,10 +55,6 @@
|
|||
|
||||
//#define DEBUG3 1 /* monitor the data detect signal. */
|
||||
|
||||
#undef EOTD_DEBUG
|
||||
|
||||
|
||||
|
||||
/*
|
||||
* Minimum & maximum sizes of an AX.25 frame including the 2 octet FCS.
|
||||
*/
|
||||
|
|
@ -418,6 +414,9 @@ int is_eotd_valid(struct hdlc_state_s *H) {
|
|||
|
||||
The apply_bch funtion requires the packet in int[63] format, with the bits arranged
|
||||
in either BCH+ATAD or ATAD+BCH format. Very odd. We'll use the first one.
|
||||
|
||||
The HCB for R2F packets must be XOR-ed with 0EED4 - since we have a leading dummy bit,
|
||||
we XOR with 0EED4 >> 1.
|
||||
*/
|
||||
static uint8_t r2f_mask[] = {0x07, 0x76, 0xa0 };
|
||||
static bch_t *bch_r2f = NULL;
|
||||
|
|
@ -459,11 +458,9 @@ int is_eotd_valid(struct hdlc_state_s *H) {
|
|||
} else {
|
||||
temp_bch = bch_r2f;
|
||||
// The HCB needs to be XOR'ed with a special constant.
|
||||
print_bytes("IN BYTES: ", H->frame_buf, H->frame_len);printf("\n");
|
||||
for (int i = 0; i < sizeof(r2f_mask); i++) {
|
||||
H->frame_buf[i] ^= r2f_mask[i];
|
||||
}
|
||||
print_bytes("XOR BYTES: ", H->frame_buf, H->frame_len);printf("\n");
|
||||
}
|
||||
|
||||
int crc_len = temp_bch->n - temp_bch->k;
|
||||
|
|
@ -473,17 +470,13 @@ print_bytes("XOR BYTES: ", H->frame_buf, H->frame_len);printf("\n");
|
|||
// +1 is to skip the dummy/parity bit.
|
||||
rotate_bits(bits + 1 , temp_bits, crc_len);
|
||||
memcpy(bits + 1, temp_bits, crc_len * sizeof(int));
|
||||
print_bits("BCH+ATAD : ", bits, 64);printf("\n");
|
||||
|
||||
// Note: bits are changed in-place.
|
||||
int corrected = apply_bch(temp_bch, bits + 1);
|
||||
printf("Corrected %d\n", corrected);
|
||||
// Put back in HCB+ATAD format
|
||||
rotate_bits(bits + 1, temp_bits, crc_len);
|
||||
memcpy(bits + 1, temp_bits, crc_len * sizeof(int));
|
||||
print_bits("COR BITS: ", bits, 64);printf("\n");
|
||||
bits_to_bytes(bits, H->frame_buf, 64);
|
||||
print_bytes("COR BYTES: ", H->frame_buf, H->frame_len);printf("\n");
|
||||
|
||||
return corrected;
|
||||
}
|
||||
|
|
|
|||
|
|
@ -1,4 +0,0 @@
|
|||
DATA_DIR=../build
|
||||
cut -c22-41,54-56,59-61,64-66,69-71,74-76,79-81,84-86,89-90 $DATA_DIR/all.out >$DATA_DIR/all.cut
|
||||
cut -d' ' -f5- $DATA_DIR/all.cut > $DATA_DIR/all.pkts
|
||||
./pkttest < $DATA_DIR/all.pkts > $DATA_DIR/all.good
|
||||
|
|
@ -1,25 +1,60 @@
|
|||
#include <stdio.h>
|
||||
#include <strings.h>
|
||||
#include "bch.h"
|
||||
#include "eotd.h"
|
||||
#include "eotd_defs.h"
|
||||
|
||||
void dump(uint8_t *bytes, char type) {
|
||||
unsigned char eotd[9];
|
||||
for (int i = 0; i < 8; i++) {
|
||||
eotd[i] = bytes[i] & 0xff;
|
||||
}
|
||||
eotd[8] = type;
|
||||
// Slice packet
|
||||
char buffer[512];
|
||||
eotd_to_text(eotd, 9, buffer, sizeof(buffer));
|
||||
printf("%s\n", buffer);
|
||||
};
|
||||
|
||||
void rotate_bytes(uint8_t *src, uint8_t *dest, int count) {
|
||||
for (int i = 0; i < count; i++) {
|
||||
dest[count - i - 1] = rotate_byte(src[i]);
|
||||
}
|
||||
}
|
||||
|
||||
int main(int argc, char **argv) {
|
||||
bch_t bch;
|
||||
int bytes[8];
|
||||
uint8_t bytes[8];
|
||||
int bits[63];
|
||||
int m, length, t;
|
||||
int count = 0;
|
||||
int rev = 0;
|
||||
char type = EOTD_TYPE_R2F;
|
||||
|
||||
init_bch(&bch, 6, 63, 3);
|
||||
#ifdef ARGS
|
||||
if (argc != 9) {
|
||||
fprintf(stderr, "Expecting 8 arguments.\n");
|
||||
|
||||
if (argc < 5) {
|
||||
fprintf(stderr, "Expecting 4+ arguments - m, length, t, type (F or R) and optionally rev to reverse the input bytes.\n");
|
||||
return -1;
|
||||
}
|
||||
|
||||
for (int i = 0; i < 8; i++) {
|
||||
sscanf(argv[i + 1], "%x", bytes + i);
|
||||
sscanf(argv[1], "%d", &m);
|
||||
sscanf(argv[2], "%d", &length);
|
||||
sscanf(argv[3], "%d", &t);
|
||||
sscanf(argv[4], "%c", &type);
|
||||
|
||||
if (argc > 5) {
|
||||
if (strcasecmp(argv[5], "rev") == 0) {
|
||||
rev = 1;
|
||||
}
|
||||
}
|
||||
#else
|
||||
|
||||
init_bch(&bch, m, length, t);
|
||||
|
||||
while (1) {
|
||||
for (int i = 0; i < 8; i++) {
|
||||
int status = scanf("%x ", bytes + i);
|
||||
int t;
|
||||
int status = scanf("%x ", &t);
|
||||
bytes[i] = t;
|
||||
if (status == EOF) {
|
||||
return 0;
|
||||
}
|
||||
|
|
@ -28,41 +63,15 @@ int main(int argc, char **argv) {
|
|||
fprintf(stderr, "Error: %d", status);
|
||||
}
|
||||
}
|
||||
#endif
|
||||
// UNEEDED
|
||||
// swap_format(bits, 45, 63);
|
||||
bytes_to_bits(bytes, bits, 63);
|
||||
int corrected = apply_bch(&bch, bits);
|
||||
if (corrected >= 0) {
|
||||
#ifdef DEBUG
|
||||
printf("%d corrected\n", corrected);
|
||||
for (int i = 0; i < 8; i++) {
|
||||
printf("%02x ", bytes[i]);
|
||||
if (rev) {
|
||||
uint8_t temp[8];
|
||||
rotate_bytes(bytes, temp, 8);
|
||||
memcpy(bytes, temp, 8);
|
||||
}
|
||||
printf("\n");
|
||||
#endif
|
||||
bits_to_bytes(bits, bytes, 63);
|
||||
for (int i = 0; i < 8; i++) {
|
||||
printf("%02x ", bytes[i]);
|
||||
}
|
||||
// Slice packet
|
||||
|
||||
printf("chain=%1x,",(bytes[0] >> 6) & 0x03);
|
||||
printf("devst=%1x,",(bytes[0] >> 4) & 0x03);
|
||||
printf("msgid=%1x,",(bytes[0] >> 1) & 0x07);
|
||||
printf("uaddr=%03x,",((bytes[0] & 0x01) << 16) | (bytes[1] << 8) | (bytes[2]));
|
||||
printf("bpres=%d,",(bytes[3] >> 1) & 0x07f);
|
||||
printf("dbit1=%02x,",((bytes[3] & 0x01) << 7) | ((bytes[4] >> 1) & 0x7f));
|
||||
printf("confm=%x,",(bytes[5] >> 7) & 0x01);
|
||||
printf("dbit2=%x,",(bytes[5] >> 6) & 0x01);
|
||||
printf("motdt=%x,",(bytes[5] >> 5) & 0x01);
|
||||
printf("ltbat=%x,",(bytes[5] >> 4) & 0x01);
|
||||
printf("ltsta=%x",(bytes[5] >> 3) & 0x01);
|
||||
printf("\n");
|
||||
printf("%04d,", count++);
|
||||
dump(bytes, type);
|
||||
}
|
||||
#ifndef ARGS
|
||||
}
|
||||
#endif
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
|
|
|||
Loading…
Reference in New Issue