Register file management for operations using a single physical register for both source and result

Abstract

A processor includes a physical register file having physical registers and an execution unit to perform an arithmetic operation to generate a result mapped to a physical register, wherein the processor delays a write of the result to the physical register file until the result is qualified as valid. A method includes mapping the same physical register both to store load data of a load-execute operation and to subsequently store a result of an arithmetic operation of the load-execute operation, and writing the load data into the physical register. The method further includes, in a first clock cycle, executing the arithmetic operation to generate the result, and, in a second clock cycle, providing the result as a source operand for a dependent operation. The method includes, in a third clock cycle, enabling a write of the result to the physical register file responsive to the result qualifying as valid.