A 20-MIPS sustained 32-bit CMOS microprocessor with high ratio of sustained to peak performance

The authors describe the design of a CPU chip with a high ratio of sustained system to peak performance (0.80). Attaining a high ratio of sustained system performance to peak performance avoids wasting circuit design effort at an architectural level through inefficient use of machine resources. The chip contains 180K transistors on a 6.98*8.73-mm² die utilizing a 1.5- mu m CMOS process to obtain a sustained system performance of 20 MIPS. By keeping the design simple and regular both at an architectural and circuit level, and by using high-level tools on the complete design, a high sustained performance was obtained with relatively little design effort (2.5 man years).