| 摘要 |
PURPOSE:To suppress the execution of a software instruction without requiring any special microprogram routine when detecting any exception concerning a variable length operand instruction or a character string instruction, etc. CONSTITUTION:A mode F/F 7 is provided to suppress the update of a register for software and the write of a main memory, microaddress stack registrer 5 is provided to store the address of the next microprogram when the microprogram to set the mode F/F 7 is executed and further, microaddress control circuit 6 is provided for continuing the execution from the microprogram at the microaddress stored in the microaddress stack register 5 when the am to reset the mode F/F 7 is executed while the mode F/F 7 is set. Thus, the execution of the software instruction can be suppressed without providing any special exception detecting program routine. |
