/*
* Determine the Syndrome Vector. Note that in s[0] we return the OR of
* all of the syndromes; this allows for an easy check for the no - error
* condition.
*/
static void syndrome(uint8_t c[ECC_CAPACITY], uint8_t s[7])
{
s[0] = 0;
for (int i = 1; i < ECC_OFFSET + 1; i++)
{
s[i] = evalpoly(c, e2v[i]);
s[0] |= s[i];
}
}
static int
get_factor(void)
{
int i, j, h;
int a0, an, na0, nan;
if (verbosing) {
push(zero);
for (i = 0; i <= expo; i++) {
push(polycoeff[i]);
push(X);
push_integer(i);
power();
multiply();
add();
}
POLY = pop();
//////printf("POLY=");
print(POLY);
//////printf("\n");
}
h = tos;
an = tos;
push(polycoeff[expo]);
divisors_onstack();
nan = tos - an;
a0 = tos;
push(polycoeff[0]);
divisors_onstack();
na0 = tos - a0;
if (verbosing) {
////printf("divisors of base term");
for (i = 0; i < na0; i++) {
////printf(", ");
print(stack[a0 + i]);
}
////printf("\n");
////printf("divisors of leading term");
for (i = 0; i < nan; i++) {
////printf(", ");
print(stack[an + i]);
}
////printf("\n");
}
// try roots
for (i = 0; i < nan; i++) {
for (j = 0; j < na0; j++) {
A = stack[an + i];
B = stack[a0 + j];
push(B);
push(A);
divide();
negate();
Z = pop();
evalpoly();
if (verbosing) {
////printf("try A=");
print(A);
////printf(", B=");
print(B);
////printf(", root ");
print(X);
////printf("=-B/A=");
print(Z);
////printf(", POLY(");
print(Z);
////printf(")=");
print(Q);
////printf("\n");
}
if (iszero(Q)) {
tos = h;
return 1;
}
push(B);
negate();
B = pop();
push(Z);
negate();
Z = pop();
evalpoly();
if (verbosing) {
////printf("try A=");
print(A);
////printf(", B=");
print(B);
////printf(", root ");
print(X);
////printf("=-B/A=");
print(Z);
////printf(", POLY(");
print(Z);
////printf(")=");
print(Q);
////printf("\n");
}
if (iszero(Q)) {
tos = h;
return 1;
}
}
}
tos = h;
return 0;
}