Register window system for reducing the need for overflow-write by prewriting registers to memory during times without bus contention

摘要

A reduced instruction set computer which adopts a configuration of controlling in a manner that in response to an access to a register file, the using state of an external bus or the like, if possible, in a period before an overflow of the register file takes place, register windows used in the procedure called in the past are made to save in advance into a stack of a memory, as a result, there is a high possibility that processing of making the register windows save into the stack of the memory has been already completed even if an overflow takes place in the register file, whereby being capable of dispensing with saving processing of the register window into the stack at this point.