}

func fieldMul(a, b fieldElement) fieldElement {
	x := uint32(a) * uint32(b)
	return fieldReduce(x)
}

// fieldMulSub returns a * (b - c). This operation is fused to save a
// fieldReduceOnce after the subtraction.
func fieldMulSub(a, b, c fieldElement) fieldElement {
	x := uint32(a) * uint32(b-c+q)
	return fieldReduce(x)
}