READ MODIFY WRITE PROCESSING METHOD AND ARITHMETIC PROCESSOR

摘要

PURPOSE: To make it possible to rapidly perform an initialization regardless of the number of words of a memory by deciding whether an access is performed for each word of a RAM at first or not and making an initial value or data be selected based on the output. ;CONSTITUTION: An initial access decision means 4 corresponds to each word of a RAM having an arithmetic part 6 and decides the two states of an unaccess and an existing access. It becomes the unaccess state by a control signal 13 operated by a processor 2 and become to be in the existing access state because data is written in a corresponded word. The output of an initial access decision means 4 is inputted as a selection signal 15 in a data selecting means 5. The data selecting means 5 is controlled by the selection signal 15, selects an initial value 14 when the word for which an access is performed has never been written and data 16 when the word has been already written, as data 17 to be calculated, and outputs them to the arithmetic part 6. Thus, the initialization by a write operation for every word becomes unnecessary.;COPYRIGHT: (C)1994,JPO&Japio