Microarchitecture description techniques

A procedure is outlined for describing the microarchitecture of a horizontal processor such that a retargetable Microprogram Compiler System can incorporate the description to generate microcode for that processor. The microarchitecture description methodology is an organized approach to defining a machine's microinstruction formats, fields, and microorders; its hardware elements; its microoperation usage rules; and its behavioral rules. To a large extent, the description procedure can be performed interactively. The link between the microarchitecture description and the microprogram compiler, termed the instruction set interpretation mechanism, is also described. Preliminary application of the microarchitecture description methodology to several real processors has shown that, despite some problems, the procedure shows promise for significantly reducing the time required to retarget a microprogram compiler.