Microprocessor with conditional cross path stall to minimize CPU cycle time length

摘要

A digital system is provided that includes a central processing unit (CPU) that has an instruction execution pipeline with a plurality of functional units for executing instructions in a sequence of CPU cycles. The execution units are clustered into two or more groups. Cross-path circuitry is provided such that results from any execution unit in one execution unit cluster can be supplied to execution units in another cluster. A cross-path stall is conditionally inserted to stall all of the functional groups when one execution unit cluster requires an operand from another cluster on a given CPU cycle and the execution unit that is producing that operand completes the computation of that operand on an immediately preceding CPU cycle.