USE_DSP - 2025.2 English - UG901

USE_DSP instructs the synthesis tool how to deal with synthesis arithmetic structures. By default, unless there are timing concerns or threshold limits, synthesis attempts to infer mults, mult-add, mult-sub, and mult-accumulate type structures into DSP blocks.

Adders, subtracters, and accumulators can go into these blocks also, but by default are implemented with the logic instead of with DSP blocks. The USE_DSP attribute overrides the default behavior and force these structures into DSP blocks.

Accepted values are: logic , simd , yes , and no :

• The logic value is used specifically for XOR structures to go into the DSP primitives. For logic, you can place the attribute on the module/architecture level only.
• The simd instructs the tool to put SIMD structures (Single-instruction-multiple-data) into DSPs. See the templates for examples.
• The yes and no values instruct the tool to either put the logic into a DSP or not. You can place these values in the RTL on signals, architecture, components, entities, and modules. The priority is:
  1. Signals
  2. Architectures and components
  3. Modules and entities

If the attribute is not specified, the default behavior is for Vivado synthesis determines the correct behavior if the attribute is not specified. You can set this attribute in RTL or XDC.