s_mp_reduce
mp_err s_mp_reduce(mp_int *x, const mp_int *m, const mp_int *mu);
if((res = s_mp_reduce(&s, m, &mu)) != MP_OKAY)
if((res = s_mp_reduce(&x, m, &mu)) != MP_OKAY)
if((res = s_mp_reduce(&s, m, &mu)) != MP_OKAY)
if((res = s_mp_reduce(&x, m, &mu)) != MP_OKAY)