EISC (Extendable Instruction Set Computer) is the specially designed instruction set that can reduce the program size and the frequency of the memory access efficiently. And it is also able to expand the values such as immediate or displacement value using expanded instructions. As a result, it has the advantages of both CISC and RISC architectures.

EISC(Extendable Instruction Set Compter,可扩展指令集计算机)是为了减少程序大小和内存访问频率而专门设计的指令集。它还具有能扩充立即数和错值的扩充指令。总之，它集CISC(Complex Instruction Set Computer复杂指令集计算机) 和 RISC(Reduced Instruction Set Computer精简指令集计算机)的优点于一身。