Allocating rename register from separate register sets for each result data of multiple data processing instruction

Multiple data processing instructions instruct a computing device to process multiple data including first data and second data. When a multiple data processing instruction is decoded, two allocatable registers are selected. One is used to store the result of a processing operation performed on first data by one processing unit, and the other is used to store the result of a processing operation performed on second data by another processing unit. Those stored processing results are then transferred to result registers. Normal data processing instructions, on the other hand, instruct a processing operation on third data. When a normal data processing instruction is decoded, one allocatable register is selected and used to store the result of processing that a processing unit performs on the third data. The stored processing result is then transferred to a result register.