Instruction fetch apparatus, processor and program counter addition control method

Abstract

An instruction fetch apparatus is disclosed which includes: a program counter configured to manage the address of an instruction targeted to be executed in a program in which instructions belonging to a plurality of instruction sequences are placed sequentially; a change designation register configured to designate a change of an increment value on the program counter; an increment value register configured to hold the changed increment value; and an addition control section configured such that if the change designation register designates the change of the increment value on the program counter, then the addition control section increments the program counter based on the changed increment value held in the increment value register, the addition control section further incrementing the program counter by an instruction word length if the change designation register does not designate any change of the increment value on the program counter.