| 摘要 |
PURPOSE:To eliminate complicated processing and to simplify control by replacing the instruction code part of an instruction word to be reported with the prescribed value in case an exception is detected when the instruction word is extracted. CONSTITUTION:An address held by an instruction counter 113 is set to a memory address register 302, and an instruction word is read out by a cache control circuit 303. If an access detecting circuit 304 detects an exception related to the memory access, the discontinuation of data read-out is indicated to the circuit 303. Then a code showing the detailed contents of the exception is set to an exception code register 101. Then an instruction word having an instruction code part replaced with the output of a constant generating circuit 106 is set to a decoded instruction register 110. An exception reception deciding circuit 115 decides the contents of both the register 110 and an exception code register 111. Then the exception processing is started to an arithmetic unit. |
