mirror of https://github.com/wb2osz/direwolf.git
Closer. Lots of ACCA data to chew on.
This commit is contained in:
David E. Tiller
parent
a707fc8225
commit
5be9e44c5b
74
src/bch.c
74
src/bch.c
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@ -75,7 +75,9 @@
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#include <string.h>
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#include "bch.h"
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int bch_init(bch_t *bch, int m, int length, int t) {
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#undef DEBUG
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int init_bch(bch_t *bch, int m, int length, int t) {
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int p[21], n;
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@ -115,14 +117,20 @@ int bch_init(bch_t *bch, int m, int length, int t) {
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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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#ifdef DEBUG
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printf("p(x) = ");
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#endif
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for (int i = 0; i <= m; i++) {
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n *= 2;
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#ifdef DEBUG
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printf("%1d", p[i]);
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#endif
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}
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#ifdef DEBUG
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printf("\n");
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#endif
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n = n / 2 - 1;
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bch->n = n;
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int ninf = (n + 1) / 2 - 1;
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@ -184,10 +192,12 @@ int bch_init(bch_t *bch, int m, int length, int t) {
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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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#ifdef DEBUG
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if (bch->m > 9) {
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printf("Computing cycle sets modulo %d\n", bch->n);
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printf("(This may take some time)...\n");
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}
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#endif
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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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@ -247,11 +257,12 @@ int bch_init(bch_t *bch, int m, int length, int t) {
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if (bch->k<0)
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{
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printf("Parameters invalid!\n");
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return -4;
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}
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#ifdef DEBUG
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printf("This is a (%d, %d, %d) binary BCH code\n", bch->length, bch->k, d);
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#endif
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/* Compute the generator polynomial */
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bch->g = malloc((rdncy + 1) * sizeof(int));
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@ -266,12 +277,13 @@ int bch_init(bch_t *bch, int m, int length, int t) {
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bch->g[jj] = bch->g[jj - 1];
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bch->g[0] = bch->alpha_to[(bch->index_of[bch->g[0]] + zeros[ii]) % bch->n];
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}
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#ifdef DEBUG
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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", bch->g[ii]);
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}
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printf("\n");
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#endif
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return 0;
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}
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@ -303,8 +315,7 @@ void generate_bch(bch_t *bch, int *data, int *bb) {
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}
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int
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apply_bch(bch_t *bch, int *recd)
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int apply_bch(bch_t *bch, int *recd)
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/*
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* Simon Rockliff's implementation of Berlekamp's algorithm.
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*
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@ -335,7 +346,9 @@ apply_bch(bch_t *bch, int *recd)
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t2 = 2 * bch->t;
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/* first form the syndromes */
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#ifdef DEBUG
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printf("S(x) = ");
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#endif
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for (i = 1; i <= t2; i++) {
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s[i] = 0;
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for (j = 0; j < bch->length; j++)
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@ -349,9 +362,13 @@ apply_bch(bch_t *bch, int *recd)
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*/
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/* convert syndrome from polynomial form to index form */
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s[i] = bch->index_of[s[i]];
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#ifdef DEBUG
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printf("%3d ", s[i]);
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#endif
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}
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#ifdef DEBUG
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printf("\n");
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#endif
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if (syn_error) { /* if there are errors, try to correct them */
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/*
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@ -451,12 +468,13 @@ apply_bch(bch_t *bch, int *recd)
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for (i = 0; i <= l[u]; i++)
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elp[u][i] = bch->index_of[elp[u][i]];
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#ifdef DEBUG
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printf("sigma(x) = ");
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for (i = 0; i <= l[u]; i++)
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printf("%3d ", elp[u][i]);
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printf("\n");
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printf("Roots: ");
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#endif
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/* Chien search: find roots of the error location polynomial */
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for (i = 1; i <= l[u]; i++)
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reg[i] = elp[u][i];
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@ -473,10 +491,14 @@ apply_bch(bch_t *bch, int *recd)
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root[count] = i;
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loc[count] = bch->n - i;
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count++;
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#ifdef DEBUG
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printf("%3d ", bch->n - i);
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#endif
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}
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}
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#ifdef DEBUG
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printf("\n");
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#endif
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if (count == l[u]) {
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/* no. roots = degree of elp hence <= t errors */
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for (i = 0; i < l[u]; i++)
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@ -484,7 +506,9 @@ apply_bch(bch_t *bch, int *recd)
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return l[u];
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}
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else { /* elp has degree >t hence cannot solve */
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#ifdef DEBUG
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printf("Incomplete decoding: errors detected\n");
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#endif
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return -1;
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}
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} else {
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@ -522,14 +546,28 @@ void bits_to_bytes(int *bits, int *byte_dest, int num_bits) {
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byte_dest[index] <<= 8 - (num_bits % 8);
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}
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void swap_format(int *bits, int cutoff, int num_bits) {
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// Do it the easy way
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int *temp = malloc(num_bits * sizeof(int));
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for (int i = 0; i < num_bits; i++) {
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if (i < cutoff) {
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temp[num_bits - cutoff + i] = bits[i];
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} else {
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temp[i - cutoff] = bits[i];
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}
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}
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memcpy(bits, temp, num_bits * sizeof(int));
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}
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void dump_bch(bch_t *bch) {
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printf("m: %d length: %d t: %d n: %d k: %d\n", bch->m, bch->length, bch->t, bch->n, bch->k);
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}
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#undef MAIN
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#undef TEST_BYTES_TO_BITS
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#define TEST_APPLY
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#define TEST_SWAP
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#ifdef MAIN
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int main()
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{
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int test[][8] = {
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@ -555,7 +593,7 @@ int main()
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int temp[8];
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bch_t bch;
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bch_init(&bch, 6, 63, 3);
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init_bch(&bch, 6, 63, 3);
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for (int count = 0; count < sizeof(test) / sizeof(*test); count++) {
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bytes_to_bits(test[count], bits, 63);
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@ -593,6 +631,21 @@ int main()
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printf("\n");
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#endif
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#ifdef TEST_SWAP
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printf("orig: ");
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for (int i = 0; i < 63; i++) {
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printf("%d ", bits[i]);
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}
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printf("\n");
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swap_format(bits, 45, 63);
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printf("rev: ");
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for (int i = 0; i < 63; i++) {
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printf("%d ", bits[i]);
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}
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printf("\n");
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#endif
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#ifdef TEST_APPLY
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int recv[63];
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@ -635,3 +688,4 @@ int main()
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#endif
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}
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}
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#endif
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10
src/bch.h
10
src/bch.h
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@ -15,8 +15,16 @@ struct bch {
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typedef struct bch bch_t;
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int bch_init(bch_t *bch, int m, int length, int t);
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int init_bch(bch_t *bch, int m, int length, int t);
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void generate_bch(bch_t *bch, int *data, int *bb);
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int apply_bch(bch_t *bch, int *recd);
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void bytes_to_bits(int *bytes, int *bit_dest, int num_bits);
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void bits_to_bytes(int *bits, int *byte_dest, int num_bits);
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void swap_format(int *bits, int cutoff, int num_bits);
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#endif
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@ -0,0 +1,4 @@
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DATA_DIR=../build
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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
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cut -d' ' -f5- $DATA_DIR/all.cut > $DATA_DIR/all.pkts
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./pkttest < $DATA_DIR/all.pkts > $DATA_DIR/all.good
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@ -0,0 +1,68 @@
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#include <stdio.h>
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#include "bch.h"
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int main(int argc, char **argv) {
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bch_t bch;
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int bytes[8];
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int bits[63];
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init_bch(&bch, 6, 63, 3);
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#ifdef ARGS
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if (argc != 9) {
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fprintf(stderr, "Expecting 8 arguments.\n");
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return -1;
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}
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for (int i = 0; i < 8; i++) {
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sscanf(argv[i + 1], "%x", bytes + i);
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}
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#else
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while (1) {
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for (int i = 0; i < 8; i++) {
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int status = scanf("%x ", bytes + i);
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if (status == EOF) {
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return 0;
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}
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if (status != 1) {
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fprintf(stderr, "Error: %d", status);
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}
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}
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#endif
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// UNEEDED
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// swap_format(bits, 45, 63);
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bytes_to_bits(bytes, bits, 63);
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int corrected = apply_bch(&bch, bits);
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if (corrected >= 0) {
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#ifdef DEBUG
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printf("%d corrected\n", corrected);
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for (int i = 0; i < 8; i++) {
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printf("%02x ", bytes[i]);
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}
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printf("\n");
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#endif
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bits_to_bytes(bits, bytes, 63);
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for (int i = 0; i < 8; i++) {
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printf("%02x ", bytes[i]);
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}
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// Slice packet
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printf("chain=%1x,",(bytes[0] >> 6) & 0x03);
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printf("devst=%1x,",(bytes[0] >> 4) & 0x03);
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printf("msgid=%1x,",(bytes[0] >> 1) & 0x07);
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printf("uaddr=%03x,",((bytes[0] & 0x01) << 16) | (bytes[1] << 8) | (bytes[2]));
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printf("bpres=%d,",(bytes[3] >> 1) & 0x07f);
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printf("dbit1=%02x,",((bytes[3] & 0x01) << 7) | ((bytes[4] >> 1) & 0x7f));
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printf("confm=%x,",(bytes[5] >> 7) & 0x01);
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printf("dbit2=%x,",(bytes[5] >> 6) & 0x01);
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printf("motdt=%x,",(bytes[5] >> 5) & 0x01);
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printf("ltbat=%x,",(bytes[5] >> 4) & 0x01);
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printf("ltsta=%x",(bytes[5] >> 3) & 0x01);
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printf("\n");
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}
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#ifndef ARGS
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}
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#endif
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return 0;
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}
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