Browse Prior Art Database

On-Chip Microcoding of a Microprocessor with only Most Frequently Used Instructions of a Large System

IP.com Disclosure Number: IPCOM000049874D
Original Publication Date: 1982-Aug-01
Included in the Prior Art Database: 2005-Feb-09

Publishing Venue

IBM

Related People

Authors:
Agnew, PW Buonomo, JP Houghtalen, SR Kellerman, AS Losinger, RE Valashinas, JW [+details]

Abstract

The performance of a processor is strongly influenced by the length of its critical path from the control store, to the data flow, to the conditional next microword address generator, and back to the control store. A microprocessor, which contains the entire critical path within one chip, can have a very short critical path, and hence a short microcycle time, without expending large amounts of power driving control store addresses and microwords across chip pins. However, currently foreseen microprocessors are limited to an on-chip control store size that will contain only about one quarter of the microcode necessary to implement a mainframe architecture.