Documentation

Select the Share Adders setting.

Leave the Adder sharing minimum bitwidth to 0.

Determine whether to perform resource sharing at the existing clock rate or at a higher clock rate. To use a higher clock rate, specify an Oversampling factor greater than 1.

Specify the StreamingFactor for Add blocks with vector inputs or outputs.

Specify the SharingFactor for Add blocks with scalar inputs or outputs.

Make sure that the input word-lengths of the Add blocks match.

For example, this figure illustrates a model containing three Add blocks placed inside a Subsystem with SharingFactor of 3. To share the Add blocks, you must insert Data Type Conversion blocks with Output data type set to int16 so that the input word lengths match.

Determine how to implement the Gain block. HDL Coder does not share Gain blocks in either of these cases:

In both these cases, the code generator uses a cast operation to replace the multiplier operations with shift and add or subtract operations, which causes sharing to be unsuccessful. In addition, if the Gain parameter is 0 or 1, then resource sharing requires no additional logic.

Specify the StreamingFactor for Gain blocks with vector inputs or outputs.

Specify the SharingFactor for Gain blocks with scalar inputs or outputs.

Determine whether to perform resource sharing at the existing clock rate or at a higher clock rate. To use a higher clock rate, specify an Oversampling factor greater than 1.

Use the same synthesis attribute settings if you specify the DSPStyle block property for the Gain blocks. HDL Coder does not share multipliers that have different synthesis attribute settings.

Specify 18 as the Multiplier partitioning threshold when targeting Xilinx^® devices and 25 as the threshold when targeting Intel^® devices. This setting creates more resource sharing opportunities for multipliers with a wide bit width, which reduces the use of DSPs on the FPGA.

Specify the Multiplier promotion threshold if you want to share Product blocks that have different word-lengths. The multiplier promotion threshold is the maximum word-length by which HDL Coder promotes a multiplier for sharing with other multipliers.

Leave the Share Multipliers setting enabled and the Multiplier sharing minimum bitwidth to 0.

Specify the StreamingFactor for the subsystems that contain Product blocks with vector inputs or outputs.

Specify the SharingFactor for the subsystems that contain Product blocks with scalar inputs or outputs.

Use a Gain block instead of a Product block when one of the inputs to the Product block is a constant. Use the constant value as the Gain parameter of the Gain block. If you use floating-point data types in the Native Floating Point mode, HDL Coder converts the Product block to a Gain block automatically during code generation. To learn more, see Simplify Constant Operations and Reduce Design Complexity in HDL Coder™.

Determine whether to perform resource sharing at the existing clock rate or at a higher clock rate. To use a higher clock rate, specify an Oversampling factor greater than 1.

Use the same synthesis attribute settings if you specify the DSPStyle block property for the Product blocks. HDL Coder does not share multipliers that have different synthesis attribute settings.

Leave the Share Multiply-Add blocks setting enabled and the Multiply-Add block sharing minimum bitwidth set to 0.

Determine whether to perform resource sharing at the existing clock rate or at a higher clock rate. To use a higher clock rate, specify an Oversampling factor greater than 1.

Specify the SharingFactor.