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Basic RISC-V CPU implementation in VHDL.

This is a RV32IMZcsr ISA CPU implementation, based off of my TPU CPU design. It is very simple, but has run rv32i-compiled GCC toolchain binaries at over 200MHz on a Digilent Arty S7-50 board, built with Xilinx Spartan 7 tools.

When used in the ArtyS7-RPU-SoC @ 100MHZ it can run DooM timedemo3 at ~8fps, and boot operating systems such as Zephyr RTOS.

The Wiki will have more in depth information:

Please let me know if you are using any of the RPU design in your own projects! I am contactable on twitter @domipheus.


Diagram does not include recently added CSR & LINT units, or the fact that interrupts are supported.

RPU Core overview

Implementation detail is written about via blogs available at

The tests in the repo are incredibly old and basic, and included only as a baseline to help. They will be expanded upon in time. The core_tb should work for basic simulator use and could be expanded for more complex debugging.

Currently working on: Privilege modes, memory system overhaul, mmu support