RISC TYPE CPU, COMPILER, MICROCOMPUTER, AND AUXILIARY ARITHMETIC UNIT

摘要

PROBLEM TO BE SOLVED: To provide a RISC type CPU simplifying constitution to the utmost, and prohibiting an interruption, when executing computation using an auxiliary arithmetic unit. SOLUTION: This CPU is provided with a dedicated command cmov decodable only by the auxiliary arithmetic unit, and the interruption is prohibited while decoding the dedicated command. Access from other device to the auxiliary arithmetic unit is thereby prevented, even when the device such as other peripheral circuit and the like is connected to the CPU. COPYRIGHT: (C)2008,JPO&INPIT