3.5.2.5 Force Register

The SmartHLS™ Scheduler will attempt to find the best approach to schedule the circuit based on the information it has at that time. Usually, this is enough to generate a hardware with good performance. However, sometimes users may want to have explicit control about certain location to insert the register. SmartHLS does provide the flexibility to force a register at specific location.

To do so, you need to include the header file:

#include "hls/utils.hpp"

and call the function hls_reg for the data you want to register as below:

val_reg = hls_reg(val);

This will force SmartHLS to register the value, val, and any operations that depend on val will be scheduled accordingly, taking into the account the 1-cycle latency required to register the value.