NutShell is an in-order linux-compatible RISC-V processor designed by five undergraduate students from University of Chinese Academy of Sciences. This processor supports RV64IMAC instruction extension and SV39 virtual-memory system. It has been typed out using SMIC 110nm process technology. The test chip can successfully boot the Linux kernel.
A cycle-level differential testing framework is used is used during development, in which an emulator (NEMU) runs side by side with the processor being tested. With the help of that framework, the develop team managed to boot linux on NutShell in a short period of time.
This talk will introduce the development process of this chip from the perspective of undergraduate students participating in the project. Experience of developing with Chisel and debugging with the differential testing framework will also be shared.
