irsim 9.7.104-1 (riscv64 binary) in ubuntu groovy

 IRSIM is a tool for simulating digital circuits. It is a "switch-level"
 simulator; that is, it treats transistors as ideal switches. Extracted
 capacitance and lumped resistance values are used to make the switch a little
 bit more realistic than the ideal, using the RC time constants to predict the
 relative timing of events.