mpihelp_mul_1
mpi_limb_t mpihelp_mul_1(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr,
cy_limb = mpihelp_mul_1(prodp, up, size, v_limb);
cy = mpihelp_mul_1(prodp, up, usize, v_limb);
cy = mpihelp_mul_1(prodp, up, size, v_limb);