A microprocessor comprises a calculation unit that (i) includes partial calculation units each operable to perform partial data calculation, and (ii) is operable to perform data calculation on N or less bits, where N is a total number of bits on which the partial calculation units are to perform data calculation. The microprocessor, when having the calculation unit perform data calculation according to an instruction fetched from a memory, controls the partial calculation units depending on a bit width mode selected in terms of a number of bits on which data calculation is to be performed, so as to either (i) have all the partial calculation units operate, or (ii) suspend operation of a predetermined number of the partial calculation units, and have the rest of the partial calculation units operate.
An objective is to perform a low power operation of a microprocessor on the pipeline stage of an instruction decode and a preceding pipeline stage without the necessity for increasing a circuit size or decoding time. An instruction code of each program for performing an instruction includes a first instruction set, which includes a flag for specifying predicate (301), and one or more second instruction sets including control specification information (302). A low power operation of each control circuit is performed for each instruction according to the instruction execution control function. Thus, without the necessity for increasing a circuit size or decoding time, it is possible to control the pipeline stage of an instruction decode and a preceding pipeline stage, achieving a low power operation of the microprocessor.
An objective is to perform a low power operation of a microprocessor on the pipeline stage of an instruction decode and a preceding pipeline stage without the necessity for increasing a circuit size or decoding time. An instruction code of each program for performing an instruction includes a first instruction set, which includes a flag for specifying predicate (301), and one or more second instruction sets including control specification information (302). A low power operation of each control circuit is performed for each instruction according to the instruction execution control function. Thus, without the necessity for increasing a circuit size or decoding time, it is possible to control the pipeline stage of an instruction decode and a preceding pipeline stage, achieving a low power operation of the microprocessor.
