Abstract: A central processing unit (CPU) for easily testing and debugging an application program, which includes a data communications unit for performing data communications with a host computer, a status register having a flag representing whether an operational mode of the CPU is a general operational mode representing a general operational state or a debugging mode representing a debugging state, a debugging stack pointer register which is used as a stack pointer designating a stack memory storing data of a debugging program, and a comparator for comparing a value stored in a break register with break data, wherein the CPU is converted into the debugging mode if the break register value is same as the break data, the flag of the status register has a value representing a debugging mode, a start address for performing a debugging program is loaded in a program counter, and the debugging program is executed to perform a debugging according to a command from the host computer via the data communications unit.

Abstract: An apparatus includes an instruction word storage for storing a plurality of general instruction words and extended instruction words, a temporary storage unit including a plurality of buffers for pre-fetching and storing the plurality of instruction words from the instruction word storage, an instruction word search unit for receiving and decoding the plurality of instruction words pre-fetched and outputting a position signal of a general instruction word and the positions of one or more successive extended instruction words stored in the temporary storage a selector for selecting a buffer in which a general instruction word is stored and outputting the general instruction word sequentially, according to the position signal a general instruction word parser for receiving a general instruction word from the selector and outputting a plurality of control signals for executing the general instruction word simultaneously, an extended data parser is provided for performing an operational processing of operands of

Abstract: A central processing unit (CPU) for easily testing and debugging an application program, which includes a data communications unit for performing data communications with a host computer, a status register having a flag representing whether an operational mode of the CPU is a general operational mode representing a general operational state or a debugging mode representing a debugging state, a debugging stack pointer register which is used as a stack pointer designating a stack memory storing data of a debugging program, and a comparator for comparing a value stored in a break register with break data, wherein the CPU is converted into the debugging mode if the break register value is same as the break data, the flag of the status register has a value representing a debugging mode, a start address for performing a debugging program is loaded in a program counter, and the debugging program is executed to perform a debugging according to a command from the host computer via the data communications unit.