Digital signal processor supporting two types of instruction sets

An architecture for a general purpose digital signal processor has been developed that enables the specification of peripherals and the core part to be easily changed for specific applications. an evaluation chip LSI providing 24-bit fixed-point arithmetic was created in order to verify the performance. This digital signal processor (DSP) basically uses RISC-type architecture in order to simplify the hardware structure and provides two types of instruction sets, called RISC-type and DSP-type instructions, to maintain the benefit of the original DSP. the RISC-type instruction set consists of several types of single-task operating commands: arithmetic, logical, data transfer, branch, etc. It provides wide operand flexibility. On the other hand, the DSP-type instruction set consists of parallel operating commands as provided for conventional DSP which execute several data processing and data transfer operations. However, operand flexibility is restricted by providing these two types of instruction sets in one LSI and a higher performance can be achieved than with conventional DSPs which have the same bit length and only one instruction set.