Rafa350 / riscv

Experimental RISCV implementation

Experimental RISCV implementation on FPGA

CPU features

• Base RV32I or RV64I
• Optional extensions E, C and M
• Optional instruction and data caches
• Classic five pipeline stages
• Harvard architecture
• Machine mode only
• CSR block
• For use in embedded systems. Optional caches, use internal FPGA memory.
• Jump address recalculated in ID stage. Zero jump flushes/stalls

Simulation

• Verilator RTL simulation
• Custom C++ app for behavioral simulation
• Verilator testbench for individual modules

Implementation

• Quartus Prime 20.1
• Terasic DE0-Nano (Cyclone-IV)

Core main files

• CorePP.sv : 5 stage pipeline
• CoreSC.sv : Single cycle processor for verification and comparation purposes
• Cache/*.sv : L1 caches
• Stage/*.sv : Files for stages
• Pipeline/*.sv : Files for pipeline registers

Future things

• Unified instruction and data memory
• L2 Cache and SDRAM interface
• Peripherical bus (Wishbone ?)
• UART
• GPIO
• Debug interface