| 摘要 |
PURPOSE:To prevent a serious destruction of the program even for somewhat of erroneous operations in a two-word instruction, by specifying the two-word instruction stored in a user program memory during the decoding execution of user instructions and by changing numerical data of the second word. CONSTITUTION:When a user instruction which is addressed by a program counter PC and is read out from a program memory 1 coincides with data of the operation code and the element number of the first word of a two-word instruction to be changed which is stored in a register A, storage address data of the user instruction is latched in a register C. A program console control part 5 adds 1 to address data stored in the register C during an interruption time to indicate an address of the second word where numerical data should be entered. A preset signal is sent to the progrqm counter PC to preset data of the register C to the PC. A write signal is then sent to the program memory 1 to write numerical data of a register B, which is applied to a data input terminal Din of the program memory 1, to said address of this memory 1. |
