Abstract: A processor having a zero-overhead operand copy capability. The processor includes multiple execution units to execute instructions in parallel and multiple register files each associated with one or more of the execution units. The processor further includes circuitry to select either an instruction execution result from a first one of the execution units or content of a register within a first one of the register files associated with the first one of the execution units to be stored within a register within a second one of the register files.