rvcore: A tiny RISC-V emulator that runs DOOM

rvcore is a RISC-V emulator that serves as a minimal environment capable of running DOOM. It implements the RV32IM ISA except for the FENCE and EBREAK instructions, which are currently stubbed.

Milestones

• Run flat binaries written in assembly

• Run flat binaries written in C

• Load ELF binaries (binaries with a single PT_LOAD segment work)

• Implement the newlib stubs needed to run DOOM

• Get DOOM to boot

• Make DOOM playable

• Implement the M extension

Build instructions

1. To build, CMake and GCC/Clang is required (for Windows, MSYS2 with mingw-w64-ucrt-x86_64-toolchain or Cygwin is needed)

2. Dependencies (SDL3): libsdl3-dev / sdl3-devel / sdl3

3. Run

       mkdir build
       cmake -B build -DCMAKE_BUILD_TYPE=Release
       cd build
       cmake --build .
   

Build instructions for doomgeneric

1. Clone https://github.com/lalitshankarch/doomgeneric
2. riscv64-unknown-elf-gcc or the riscv64-gnu-toolchain configured with ./configure --with-multilib-generator="rv32im-ilp32--" must be installed
3. Navigate to doomgeneric and run make

Running other programs

Navigate to the examples directory to see how to run simple C programs on rvcore. Only a few essential newlib stubs are implemented.

To implement a new stub, first modify stubs.h and then add the appropriate handler in cpu.cpp.