Microword generation mechanism utilizing a separate branch decision programmable logic array

摘要

A microword generation mechanism is provided for producing the sequences of microwords used to control the execution of processor instructions in a microprogrammed digital data processor. This microword generation mechanism includes programmable logic array means responsive to the processor instructions for producing the appropriate microword sequences. The microword generation mechanism also includes condition indicator circuitry for supplying indicator signals indicating whether the results of arithmetic and logic operations in the processor meet certain types of conditions. The microword generation mechanism further includes a condition testing programmable logic array responsive to the condition field of a conditional branch type processor instruction for testing the appropriate indicator signal or signals and causing a branch type microword sequence to be produced if the specified condition is met.