A VLIW GEOMETRY PROCESSOR WITH SOFTWARE BYPASS MECHANISM

This paper describes the 'Procyon' processor which is to be used for g eometry processing. The objective of this processor is to provide a hi gh performance geometry processor to support next generation 3D graphi cs such as game and CAD applications. The Procyon processor is a four parallel VLIW processor which makes hardware logic simple. We are purs uing performance improvement by compiler optimization. Procyon has a u nique feature called 'Software bypass' as well as special hardware to support 3D graphics processing. Software bypass enables the compiler t o make accesses to data on hardware bypass lines. By using this inform ation, the compiler can schedule instructions much more freely and gen erates efficient VLIW code. Other features of Procyon are multiply-add -accumulate instruction, SIMD instructions and clipping instructions. Procyon VLIW code is held in compacted form, which improves memory per formance. A program development environment, such as a pipeline simula tor and an assembly code parallelizer, is also prepared for system and application programmers. Preliminary simulation results demonstrate t hat a performance of 2.6 M polygons per second at 125 MHz Procyon is a ttained.