DSP Block Implementation - 2022.1 English

Vivado Design Suite User Guide: Synthesis (UG901)

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2022.1 English

When implementing a Multiplier in a single DSP block, Vivado synthesis tries to take advantage of the pipelining capabilities of DSP blocks. Vivado synthesis pulls up to two levels of registers present: On the multiplication operands, and after the multiplication.

When a Multiplier does not fit on a single DSP block, Vivado synthesis decomposes the macro to implement it. In that case, Vivado synthesis uses either of the following:

Several DSP blocks

A hybrid solution involving both DSP blocks and slice logic

Use the KEEP attribute to restrict absorption of Registers into DSP blocks. For example, if a Register is present on an operand of the multiplier, place KEEP on the output of the Register to prevent the Register from being absorbed into the DSP block.