MDCSIM A COMPILED EVENT-DRIVEN MULTI- DELAY SIMULATOR.pdfVIP

MDCSIM: A COMPILED EVENT-DRIVEN MULTI- DELAY SIMULATOR Yun-Sik Lee Peter M. Maurer Department of Computer Science and Engineering University of South Florida Tampa, FL 33620 MDCSIM: A COMPILED EVENT-DRIVEN MULTI- DELAY SIMULATOR ABSTRACT This paper describes a complied event driven logic simulator which allows gates to have delays that are integral multiples of some basic time unit. The nets and gates of a circuit are compiled into a routines that perform the evaluation of gates and process events. These routines also manage the current timing wheel slot and insert events into the appropriate future time slots. A threaded code implementation is used to reduce execution time and space. Experimental results have shown a 26% improvement in execution time for compiled simulation over a standard event driven simulator. MDCSIM: A COMPILED EVENT-DRIVEN MULTI- DELAY SIMULATOR Introduction. As the design of a circuit proceeds, it is necessary to simulate circuits behavior more and more accurately. In particular, more and more accurate timing models are needed. During the final phases of the design it is usually necessary to deal with the delays of the individual elements more accurately than is possible with a unit-delay or zero-delay simulator. Recently there has been much renewed interest in compiled simulation, particularly because it promises to provide better performance than is normally provided by interpreted simulators[1-9]. Although there are many well-known compiled simulation algorithms, these are based on the zero delay or the unit delay timing models. These timing models do not provide an accurate model of the circuits timing behavior. For some circuit elements, such as delay lines, multivibrators and inverters, delay is the essential nature of their function, and a reasonably accurate timing model is necessary to model their behavior. This paper focuses on the multi-delay timing model, in which the delay of each gate is modeled as an integral multipl