8.4. Debugging BOOM

In addition to the default debugging techniques specified in Debugging RTL, single-core BOOM designs can utilize the Dromajo co-simulator (see Dromajo) to verify functionality.


Dromajo currently only works in single-core BOOM systems without accelerators.


Dromajo currently only works in VCS simulation and FireSim.

8.4.1. Setting up Dromajo Co-simulation

Dromajo co-simulation is setup to work when three config fragments are added to a BOOM config.

  • A chipyard.config.WithTraceIO config fragment must be added so that BOOM’s traceport is enabled.
  • A chipyard.iobinders.WithTraceIOPunchthrough config fragment must be added to add the TraceIO to the ChipTop
  • A chipyard.harness.WithSimDromajoBridge config fragment must be added to instantiate a Dromajo cosimulator in the TestHarness and connect it to the ChipTop’s TraceIO

Once all config fragments are added Dromajo should be enabled.

To build/run Dromajo with a BOOM design, run your configuration the following make commands:

# build the default Dromajo BOOM config without waveform dumps
# replace "DromajoBoomConfig" with your particular config
make CONFIG=DromajoBoomConfig ENABLE_DROMAJO=1

# run a simulation with Dromajo
make CONFIG=DromajoBoomConfig ENABLE_DROMAJO=1 BINARY=<YOUR-BIN> run-binary