HL5: A 32-bit RISC-V processor designed with HLS

This is a high-level description in SystemC of an in-order 32-bit RISC-V core.

Installing the RISC-V toolchain

Test programs must be compiled with the RISC-V toolchain.

git clone --recursive https://github.com/riscv/riscv-gnu-toolchain.git
cd riscv-gnu-toolchain
mkdir build
cd build
../configure --prefix=<custom_target_path> --with-arch=rv32ima --with-abi=ilp32
make

To compile the test programs, make sure that riscv32-unknown-elf-gcc is PATH.

cd <hl5>/soft
make

Simulating and Synthesizing HL5

Simulation and synthesis run within the Cadence Stratus HLS 17.2 environment. In addition to Stratus HLS, simulation is configured to use Incisive as the RTL and SystemC simulator. You may change this configuration from the Stratus project.tcl script.

For instance, to run HLS and generate RTL for the BASIC HLS configuration, enter the HLS folder and run the following target.

cd <hl5>/hls
make hls_BASIC

To run a simulation of the C program soft/aes256_1.c, compile the test programs, then execute the following targets.

cd <hl5>/hls
# Behavioral simulation
make sim_BEH_aes256_1_P
# RTL simulation for BASIC HLS configuration
make sim_BASIC_aes256_1_V
# RTL simulation with GUI support
make debug_BASIC_aes256_1_V

The simulation will print on screen the content of the program counter, the instruction register and the register file. Colors highlight stalls (in red), registers for which there is a pending write back (yellow) and registers that have been updated during the latest instruction commit.

The target for synthesis is set to the Xilinx Artix7 FPGA, which is available on the ZYNQ SoCs.

If you use this work, please reference the following paper.

HL5: A 32-bit RISC-V Processor Designed with High-Level Synthesis. Paolo Mantovani, Robert Margelli, Davide Giri, and Luca P. Carloni. In the Proceedings of the Custom Integrated Circuits Conference (CICC), 2020.