Selections between alternate control word and current instruction generated control word for alu in respond to alu output and current instruction

摘要

A processor for use in a digital data processing system includes a data path which, in the execution of a program instruction, processes generally a series microinstructions from a control circuit. In some cases, the operation to be performed by the data path depends on the results of a previous operation. The data path includes a circuit which generates preset operation codes and a multiplexer which, during those cases, enables either the microinstructions from the control circuit or the preset operation code depending on the results of the previous operation.