> narvie

A Read Eval Print Loop (REPL) for RISC-V instructions. Only UNIX systems have been tested. narvie stands for native RISC-V instruction evaluator.

Installation

Either download a pre-built narvie binary (ubuntu linux, mac OS) or build using cargo:

1. Download Rustup and install Rust.
2. Install verilator. Version 3.916 is recommended.
3. Run $ cargo install narvie-cli.

Running

narvie can be run either as a simulation or by connecting a narvie processor (running on an FPGA) to your computer.

Once the cli is running type RISC-V instructions into the prompt. Examples are nop, li t0, 1678, or addi t0, t0, 1. narvie will compile the instructions into binary, run them and display the new micro-architectural state (currently only the values of the registers are displayed). When done, use ctrl-c to quit narvie.

Simulation

• To start a simulation try $ narvie-cli --simulate.

Running on an FPGA

• After connecting a narvie processor to your computer via usb run $ narvie-cli ADDRESS --baud 115200 where ADDRESS is the serial port to which the processor is connected to. Replace 115200 with the baud rate that the processor is configured to use.

Building narvie

To build narvie-cli, verilator is needed. To synthesise the verilog and flash to an FPGA ./progMDP uses yosys, arachne-pnr and icestorm. However, other tools can also be used for sythensis.

• Download Rustup and install Rust. (https://www.rust-lang.org/tools/install)
• Clone this repository.
• Run cargo build to build narvie-cli.
• From the processor directory, run ./progMDP to generate narvie-processor's byte stream and to flash a lattice Mobile Development Board.

Documentation

• REPL documentation
• Processor documentation

Demo

This demo shows the RISC-V REPL running in a simulation.

License

As this project borrows GPL licensed code from other sources it too is licensed under the GPL.

Acknowledgements

The risc-v processor was implemented based on verilog modules developed by Ryan Voo @rjlv2. The only modifications made to the processor were related to breaking the pipeline and instruction fetch mechinisms to allow instructions to be executed individually.

The verilog UART modules can be found at https://github.com/FPGAwars/FPGA-peripherals.

The verilator UART simulator testbench code (testbench/uartsim.h and testbench/uartsim.c) are implemented based on http://zipcpu.com/blog/2017/06/21/looking-at-verilator.html.

Minimum Version of Rust

narvie will officially support current stable Rust only.

Citing narvie in research

Harry Sarson, Ryan Voo, and Phillip Stanley-Marbell. "Evaluating RISC-V Instructions Natively with Narvie". Poster, Proceedings of the European Conference on Systems (EuroSys'19). Dresden, Germany, March 2019.

BibTeX:

    @inproceedings{Sarson:2019,
    author = {Harry Sarson and Ryan Voo and Phillip Stanley-Marbell},
    title = {Evaluating RISC-V Instructions Natively with Narvie},
    booktitle = {Proceedings of the  European Conference on Systems},
    series = {EuroSys'19},
    year = {2019},
    location = {Dresden, Germany},
    numpages = {2},
    publisher = {ACM},
    address = {New York, NY, USA},
    }