Electronic calculating apparatus utilizing stored programme control including programme interrupt for alternate sequences

Claim 1

PROGRAM CONTROL APPARATUS FOR CONTROLLING PROCESSING OPERATIONS PERFORMED IN ELECTRONIC DATA PROCESSING APPARATUS ON INFORMATION IN RESPONSE TO A SUCCESSION OF INSTRUCTIONS EACH DEFINING A PROGRAM STEP DERIVED FROM A SEQUENCE OF SEPARATELY ADDRESSABLE STORAGE LOCATIONS OF A MAIN STORAGE DEVICE, INCLUDING AN OPERATION REGISTER AND A STORAGE REGISTER, WHICH APPARATUS IS RESPONSIVE TO THE TRANSFER INTO THE OPERATION REGISTER OF A LOADING INSTRUCTION SPECIFYING THE ADDRESS OF A LOCATION IN THE MAIN STORAGE DEVICE TO CAUSE A MAIN PROGRAM INSTRUCTION STORED IN THE SPECIFIED ADDRESS TO BE TRANSFERRED TO THE OPERATION REGISTER CONCURRENTLY WITH THE TRANSFER OF THE LOADING INSTRUCTION OUT OF THE OPERATION REGISTER INTO THE STORAGE REGISTER, MEANS FOR MODIFYING THE LOADING INSTRUCTION DURING THIS TRANSFER TO SPECIFY THE ADDRESS OF THE NEXT REQUIRED MAIN PROGRAM INSTRUCTION, MEANS FOR RETRANSFERRING THE MODIFIED LOADING INSTRUCTION BACK INTO THE OPERATION REGISTER AT THE CONCLUSION OF A PROGRAM STEP WHEREBY THE OPERATIONS OF LOADING AND PROCESSING IN RESPONSE TO THE MAIN PROGRAM INSTRUCTIONS PROCEEDS ALTERNATELY, MEANS FOR ENTERING A LOADING INSTRUCTION DIRECTLY INTO THE OPERATION REGISTER TO INTERRUPT THE MAIN PROGRAM AND MEANS FOR TRANSFERRING A MODIFIED LOADING INSTRUCTION RELATING TO THE MAIN PROGRAM FROM THE STORAGE REGISTER INTO A PREDETERMINED LOCATION OF THE MAIN STORAGE DEVICE.