Code Size Reduction (like Zc) with ISAX macro instructions

The SCAIE-V interface is a portable interface for extending RISC-V core with custom instructions. It applies to both pipelined and non-pipelined core. The custom instructions supported do not just cover Register-type instructions, but also extend to custom control flow (jumps, branches) and custom memory operations. SCAIE-V supports executing complex custom instructions more efficiently by decoupling their execution from the base processor, and automatically inserting the required hazard handling logic to guarantee their correct interoperation with regular RISC-V instructions.

ETISS is a C++ ISS (Instruction Set Simulator), which is designed to simulate instructions for a target core on a host computer. It translates binary instructions into C code and appends translated code into a block, which will be compiled and executed at runtime. As aforementioned, it is Extendable, thus it supports myriad level of customization by adopting the technique of plug-ins. ETISS supports varied Instruction Set Architectures (ISAs) according to user needs (see architecture models in ArchImpl/).