GSIM: A Fast RTL Simulator for Large-Scale Designs

GSIM accepts chirrtl, and compiles it to C++

Prerequisites

• Install GMP, clang 19(+).

Quick Start

• GSIM provides 4 RISC-V cores ready for simulation: ysyx3, Rocket, BOOM, XiangShan.

• To try GSIM, using

  $ make init
  $ make run dutName=core
  

• Set core to ysyx3, rocket, small-boom, large-boom, minimal-xiangshan or default-xiangshan

Usage

• Run make build-gsim to build GSIM
• Run build/gsim/gsim $(chirrtl-file) to compile chirrtl to C++
• Refer to build/gsim/gsim --help for more information
• See C++ harness example to know how it interacts with the emitted C++ code.

FST Waveform Generation

GSIM supports FST waveform generation for debugging and analysis. You can control this feature via Makefile:

• Enable FST waveform: Add -DFST_WAVE to FST_CFLAGS in Makefile

  FST_CFLAGS = -DFST_WAVE -I$(abspath include/libfst)
  

• Disable FST waveform: Remove -DFST_WAVE from FST_CFLAGS

  FST_CFLAGS = -I$(abspath include/libfst)
  

When enabled, the generated C++ model will produce .fst waveform files that can be viewed with tools like GTKWave.