VERFAHREN UND DATENVERARBEITUNGSANLAGE ZUR DURCHFUEHRUNG EINER BEFEHLSMODIFIKATION

摘要

Data processing apparatus incorporates a prewritten instruction store and instruction driver hardware which mitigates the relative inflexibility of a prewritten instruction store without undue extra cost or operating time overhead. A read only instruction store 1' is connected to an adder 15 together with the output from output latches 21 of a writable data store 2. The output of the adder is connected to the instruction register 7'. In response to one native instruction in the instruction register 7', the data store 2' is accessed and its output is held in the latches 21. In response to another native instruction in the instruction register 7', the instruction store 1' is accessed and its output is added to the output of the latches 21 in the adder 15 and the modified instruction is entered into the instruction register 7' thus providing simple direct instruction modification.