Pipeline-controlled information processing system for generating updated

Abstract

The system includes a fetching circuit which sequentially fetches instructions to be executed. Certain of the instructions require that a predetermined condition code be present prior to being executed and certain of the instructions cause a condition code to be generated as a result of their execution. Condition code generators are provided for generating condition codes in response to execution of the instructions causing generation of condition codes. A circuit is also provided which is responsive to the sequentially fetched instructions for individually determining which of the instructions is to cause generation of a condition code, and which of the condition code generators is to generate a condition code for each of the determined instructions. The determined condition code generators are monitored, and a decision is made as to when a valid condition code has been generated by the monitored generator. A signal is produced when a valid condition code is generated. A decision circuit is connected to the fetching circuit for deciding which of the instructions requires the presence of a condition code prior to being executed. The decision circuit is connected to receive the signal indicative of a generated valid condition code, and is connected to inhibit the fetching circuit when a next sequential instruction requires the presence of a valid condition code and the signal is not present.