Microcode: Difference between revisions

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Revision as of 05:02, 6 January 2003

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A '''microprogram''' is a program consisting of '''microcode''' that controls the different parts of a computer's central processing unit ([[CPU]]). The [[memory]] in which it resides is called a [[control store]]. It is the modern form of the logic of a computer's [[control unit]].

Before 1955, the control logic for central processing units was designed by ad-hoc methods. One of the simplest was to use rings of [[flip-flopsflop]]s to sequence the computer's control logic.

In [[1955]] [[Maurice Wilkes]] had a fundamental insight. He realized that if one takes the control signals for a computer, one could understand them as being played much like a player-piano roll. That is, they are controlled by a sequence of very wide words constructed of bits.