VexRiscv (RV32IM CPU)
VexRiscv is an fpga friendly RISC-V ISA CPU implementation with following features :
- RV32IM instruction set 
- Pipelined on 5 stages (Fetch, Decode, Execute, Memory, WriteBack) 
- 1.44 DMIPS/Mhz when all features are enabled 
- Optimized for FPGA 
- Optional MUL/DIV extension 
- Optional instruction and data caches 
- Optional MMU 
- Optional debug extension allowing eclipse debugging via an GDB >> openOCD >> JTAG connection 
- Optional interrupts and exception handling with the Machine and the User mode from the riscv-privileged-v1.9.1 spec. 
- Two implementation of shift instructions, Single cycle / shiftNumber cycles 
- Each stage could have bypass or interlock hazard logic 
- FreeRTOS port https://github.com/Dolu1990/FreeRTOS-RISCV 
Much more information there : https://github.com/SpinalHDL/VexRiscv