Atmel SAM9X25, Manual

Page: 354 / 1145

354
11054A–ATARM–27-Jul-11
SAM9X25
The output of the procedure is the error location polynomial named smu (sigma mu). The poly-
nomial coefficients belong to the field. The smu[N1][] is a table that contains all
these coefficients.
NB_ERROR_MAX defines the maximum value of the error correcting capability.
NB_ERROR defines the error correcting capability selected at encoding/decoding time.
NB_FIELD_ELEMENTS defines the number of elements in the field.
int get_sigma()
{
int i;
int j;
int k;
/* mu */
int mu[NB_ER2];
/* sigma ro */
int sro[2*NB_ER1];
/* discrepancy */
int dmu[NB_ER2];
/* delta order */
int delta[NB_ER2];
/* index of largest delta */
int ro;
int largest;
int diff;
/* */
/* First Row */
/* */
/* Mu */
mu[0] = -1; /* Actually -1/2 */
/* Sigma(x) set to 1 */
for (i = 0; i < (2*NB_ER1); i++)
smu[0][i] = 0;
smu[0][0] = 1;
/* discrepancy set to 1 */
dmu[0] = 1;
/* polynom order set to 0 */
lmu[0] = 0;
/* delta set to -1 */
delta[0] = (mu[0] * 2 - lmu[0]) >> 1;
/* */
/* Second Row */
/* */
/* Mu */
mu[1] = 0;
/* Sigma(x) set to 1 */
for (i = 0; i < (2*NB_ER1); i++)