Mimic: a fast system/370 simulator

Abstract

Software simulation of one computer on another tends to be slow. Traditional simulators typically execute about 100 instructions on the host machine per instruction simulated. Newer simulators reduce the expansion factor to about 10, by saving and reusing translations of individual instructions. This paper describes an experimental simulator which takes the progression one step further, translating groups of instructions as a unit. This approach, combined with flow analysis, reduces the expansion factor to about 4. The new simulator simulates System/370 on a RISC, namely the IBM RT PC.