// Compute inverse of an fpe, store result in rop:
void fpe_invert(fpe_t rop, const fpe_t op1)
{
fpe_set(rop,op1);
int i;
for(i = 254; i >= 0; i--)
{
fpe_mul(rop,rop,rop);
if(scalar_getbit(bn_pminus2, i))
fpe_mul(rop,rop,op1);
}
}
// Inverse multiple of an fp2e, store result in rop:
void fp2e_invert(fp2e_t rop, const fp2e_t op)
{
#ifdef N_OPS
invfp2ctr += 1;
#endif
/* New version */
fp2e_t d1, d2;
int i;
fp2e_parallel_coeffmul(d1, op, op);
for (i = 0; i < 24; i += 2)
d1->v[i] = d1->v[i + 1] = d1->v[i] + d1->v[i + 1];
fp2e_short_coeffred(d1);
for (i = 0; i < 24; i += 2) {
d2->v[i] = op->v[i];
d2->v[i + 1] = -op->v[i + 1];
}
fp2e_set(rop, d1);
for (i = 254; i >= 0; i--) {
fp2e_parallel_coeffmul(rop, rop, rop);
if (scalar_getbit(bn_pminus2, i))
fp2e_parallel_coeffmul(rop, rop, d1);
}
fp2e_parallel_coeffmul(rop, rop, d2);
}
