bn_poly_synthetic_division routine

void
bn_poly_synthetic_division(register struct bn_poly *quo, register struct bn_poly *rem, register const struct bn_poly *dvdend, register const struct bn_poly *dvsor)
{
    register size_t divisor;
    register size_t n;

    *quo = *dvdend;
    *rem = bn_Zero_poly;

    if (dvsor->dgr > dvdend->dgr) {
    quo->dgr = -1;
    } else {
    quo->dgr = dvdend->dgr - dvsor->dgr;
    }
    if ((rem->dgr = dvsor->dgr - 1) > dvdend->dgr)
    rem->dgr = dvdend->dgr;

    for (n=0; n <= quo->dgr; ++n) {
    quo->cf[n] /= dvsor->cf[0];
    for (divisor=1; divisor <= dvsor->dgr; ++divisor) {
        quo->cf[n+divisor] -= quo->cf[n] * dvsor->cf[divisor]; /* seg fault here... */
    }
    }
    for (n=1; n<=(rem->dgr+1); ++n) {
    rem->cf[n-1] = quo->cf[quo->dgr+n];
    quo->cf[quo->dgr+n] = 0;
    }
}