| 摘要 |
PURPOSE:To allow instruction alteration for the execution of tracing, etc. by storing data which is transmitted by an instruction from a central processing unit altering a control program of an I/O controller in an address of a control program area. CONSTITUTION:To allow a no-operation instruction (NOP) to be incorporated into a main program, the instruction is incorporated beforehand into an I/O controller. When a circuit controller receives control program alteration command from a central processing unit, the controller transmits data and sets 1-3 data to a work registor (LR)7. Data 1 is set to a data address registor (DAR)8 and data 2 is stored in a memory 3. The data 1 is incremented by ''1'' and data 3 is set to the DAR 8, and the data 1 which has been incremented by ''1'' is stored in the memory 3, thereby completing the control program alteration command. Therefore, operations such as tracing can be executed easily without an increase in effects on the original program. |
