1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
|
/* Reed-Solomon encoder
* Copyright 2002, Phil Karn, KA9Q
* May be used under the terms of the GNU General Public License (GPL)
*/
#include <string.h>
#ifdef FIXED
#include "fixed.h"
#elif defined(BIGSYM)
#include "int.h"
#else
#include "char.h"
#endif
void ENCODE_RS(
#ifndef FIXED
void *p,
#endif
DTYPE *data, DTYPE *bb){
#ifndef FIXED
struct rs *rs = (struct rs *)p;
#endif
int i, j;
DTYPE feedback;
memset(bb,0,NROOTS*sizeof(DTYPE));
for(i=0;i<NN-NROOTS;i++){
feedback = INDEX_OF[data[i] ^ bb[0]];
if(feedback != A0){ /* feedback term is non-zero */
#ifdef UNNORMALIZED
/* This line is unnecessary when GENPOLY[NROOTS] is unity, as it must
* always be for the polynomials constructed by init_rs()
*/
feedback = MODNN(NN - GENPOLY[NROOTS] + feedback);
#endif
for(j=1;j<NROOTS;j++)
bb[j] ^= ALPHA_TO[MODNN(feedback + GENPOLY[NROOTS-j])];
}
/* Shift */
memmove(&bb[0],&bb[1],sizeof(DTYPE)*(NROOTS-1));
if(feedback != A0)
bb[NROOTS-1] = ALPHA_TO[MODNN(feedback + GENPOLY[0])];
else
bb[NROOTS-1] = 0;
}
}
|
