Abstract: An apparatus and a method of data processing system that uses multiply-accumulate instructions. The apparatus for processing data includes, a special register bank of N-bit data processing registers, a general register bank of N-bit data processing registers, a selector, a multiplier and an accumulator. The selector is coupled to the special register bank and the general register bank and is used for selecting one of the special and general register banks and outputting N-bit data from the selected register banks. The outputted N-bit data and the N-bit data held in the general register bank form a 2N-bit addition operand. The multiplier is used for performing multiply operation upon a first operand and a second operand and outputting an 2N-bit result. The accumulator is coupled to the multiplier, the selector and the general register bank and is used for performing accumulate operation upon the 2N-bit result and the 2N-bit addition operand and outputting a 2N-bit accumulated result.

Abstract: An apparatus and method for executing an instruction with a register bit mask for transferring data between a plurality of registers and memory inside a processor is provided. The method includes adding the N bits in the N-bit decode information together to form an initial count value, and generating a plurality of register identification (ID) numbers equivalent in number to the initial count value. The register ID numbers correspond to the positions in the N-bit decode information that has a bit value ‘1’. According to the register ID number, a link is created between the plurality of registers corresponding to the register ID numbers and a memory unit so that the memory unit and the registers are free to exchange stored data.

Abstract: An apparatus and method for executing block data transfer instruction inside a processor. The apparatus is capable of finding out the registers and their corresponding addresses that must be processed from the decode information of a register list. By processing the data in the specified registers only, program code as well as memory access cycles can be reduced and performance of the processor can be improved.

Abstract: A coprocessor data access control method having a coprocessor memory access instruction with a coprocessor indicating field such that the quantity of word data to be transmitted between the coprocessor and the memory unit can be determined. The coprocessor indicating field actually includes a coprocessor number field and a coprocessor register field. The coprocessor number field indicates the particular coprocessor to be used while the coprocessor register field indicates the particular registers to be used.

Abstract: A memory data access structure and an access method suitable for use in a processor. For each instruction executed by the processor, the execution results are recognized by the processor and transferred to a cache memory via control signals. When the instruction to be fetched is not stored in the cache memory, according to the control signals, the cache memory can determine whether the instruction is to be fetched from an external memory. With such structure, no matter whether the processor comprises a branch prediction mechanism or not, many operation clock cycles consumed in the processor of the prior art are saved by compensating for the situation that the cache memory fails to fetch, that is, a Miss of the cache memory. The efficiency and performance of the processor can be effectively enhanced.

Abstract: A data processing apparatus for executing multiple instruction sets.