Pegasus-an ASIC implementation of high-performance PROLOG processor

Pegasus is a single chip RISC microprocessor dedicated to the PROLOG language. Although implementing many ideas for the fast execution of PROLOG programs, its datapath and control are still kept very simple in line with RISC design. A prototype chip of Pegasus was fabricated in 1.5μm CMOS technology and integrates 80000 transistors in a 9.7 mm square chip area. For quick fabrication and design scalability, the chip was designed by using high-level design tools except for its register file which is a dedicated dual-port RAM with a special copy function. Although the machine cycle time is slower, the prototype chip achieves comparable performance to other dedicated machines