Dromajo - Esperanto Technology's RISC-V Reference Model
Functional verification is key to have a strong RISC-V ecosystem. Esperanto is releasing Dromajo to help the RISC-V community. Dromajo is the Esperanto translation for an emu bird. It is a RISC-V RV64GC emulator designed for RTL co-simulation. This is the emulator used for cosimulation inside Esperanto, but it is designed with a simple API that can be leveraged to other RTL RISC-V cores.
Dromajo enables executing application (such as benchmarks running on Linux) under fast software simulation, generating checkpoints after a given number of cycles, and resuming such checkpoints for HW/SW co-simulation. This has proven to be a very powerful way to capture bugs, especially in combination with randomized tests.
Dromajo's semantic model is based on Fabrice Bellard's RISCVEMU (later renamed TinyEMU), but extensively verified, bug-fixed, and enhanced to take it to ISA 2.3/priv 1.11.
Building
mkdir build
cd build
# Debug build
cmake ..
# Release build Ofast compile option
cmake -DCMAKE_BUILD_TYPE=Release ..
make
The resulting artifacts are the dromajo simulator and the
libdromajo_cosim.a library with associated dromajo_cosim.h
header file.
Check the setup.md for instructions how to compile tests like booting Linux and baremetal for dromajo.
Usage
The co-simulation environment will link with the libraries and usage
will depend on that, but the src/dromajo.c utility allows for standalone
simulation of RISC-V ELF binaries.
./dromajo
error: missing config file
usage: ./dromajo [--load snapshot_name] [--save snapshot_name] [--maxinsns N] [--memory_size MB] config
--load resumes a previously saved snapshot
--save saves a snapshot upon exit
--maxinsns terminates execution after a number of instructions
--terminate-event name of the validate event to terminate execution
--trace start trace dump after a number of instructions
--memory_size sets the memory size in MiB (default 256 MiB)
./dromajo path/to/your/coremark.riscv
...