Vivado synthesis infers multiplier macros from multiplication operators in the source code. The resulting signal width equals the sum of the two operand sizes. For example, multiplying a 16-bit signal by an 8-bit signal produces a result of 24 bits.
Recommended: If you do not intend to use all most
significant bits of a device, AMD recommends that you reduce the
size of operands to the minimum needed, especially if the Multiplier macro is
implemented on slice logic.