#### 15.1.8 Unbalanced Multiplication

Multiplication of operands with different sizes, both below
`MUL_TOOM22_THRESHOLD`

are done with plain schoolbook multiplication
(see Basecase Multiplication).

For really large operands, we invoke FFT directly.

For operands between these sizes, we use Toom inspired algorithms suggested by
Alberto Zanoni and Marco Bodrato. The idea is to split the operands into
polynomials of different degree. GMP currently splits the smaller operand
into 2 coefficients, i.e., a polynomial of degree 1, but the larger operand
can be split into 2, 3, or 4 coefficients, i.e., a polynomial of degree 1 to
3.