| 摘要 |
PURPOSE:To perform emulation by complete single-step operation by inserting a no-operation instruction forcibly every time a target instruction is executed, and by generating an interruption which can not be inhibited during the instruction execution. CONSTITUTION:Every time a microprocessor 1 executes one of program instructions stored in a storage device 3, it reads a no-operation instruction out of a no- operation instruction storage device 15 to a data bus 4, thereby executing this no- operation instruction. Then, a request for an interruption which can not be inhibited is sent, in response to a signal from a status detecting circuit 10, to a microprocessor 1 through an interruption signal selection circuit 12 at a point in time a little bit behind the execution start of the no-operation instruction. This request for the interruption returns the control from the execution of the instructions stored in the storage device 3 to a control program in a storage device 2. |
