GB1314486A - Microprogramme control system - Google Patents

Abstract

1314486 Data processing INTERNATIONAL BUSINESS MACHINES CORP 4 Aug 1971 36616/71 Heading G4A A microprogramme control system which controls the flow of data in a data processing system includes a number of cyclically operating associative stores (referred to as state stores) (14, Fig. 1, not shown), which, in each cycle, provide data for control of the flow. The system also includes a sequence control store (12), which may also be associative and which operates synchronously with the state stores. The sequence store contains control words comprising as many control fields (CF) as there are state stores. The data read from a state store is selected by an associative search using a search argument including both the content of a corresponding control field of a control word read from the sequence store and at least part of the data read from the state store during the preceding cycle. The search argument may also include data from other state stores and data resulting from the data flow. As described each sequence control word includes an identification of the first of a set of control words. The sequence store holds ordered sets of such words, each set causing the data flow to execute a minioperation and each control word defining a different minioperation. When data identifying the first word is fed to the sequence store the control words of the corresponding set are read out in sequence to the state store. An interrupt signal generated by the data flow selects a control word according to the operations to be executed by the data flow in response to the interrupt.