초록 ▼

A data processing system having a control store storing firmware words for controlling the system, logic for executing logical operations on input data, including the performing of a first and second data processing routine, and apparatus for addressing the control store to access selected firmware

A data processing system having a control store storing firmware words for controlling the system, logic for executing logical operations on input data, including the performing of a first and second data processing routine, and apparatus for addressing the control store to access selected firmware words to control the execution of desired logical operations on the input data. The system operates in a particular mode of control to suspend the operation of the first routine in order to execute the second routine whereby the logical apparatus includes a register for saving a return address associated with the last instruction of the first routine. When the system terminates the second routine and restores the first routine to operation, the contents of the save register are employed, with the lowest order bit thereof inverted, to access the control store to fetch the firmware word used to reenter the first routine.

대표청구항 ▼

Apparatus for effecting subroutining in a data processing system, said apparatus comprising: A. logic means for performing logical operations on input data, including the performing of a first routine and a second routine for processing said input data; B. storage means having a plurality of control

Apparatus for effecting subroutining in a data processing system, said apparatus comprising: A. logic means for performing logical operations on input data, including the performing of a first routine and a second routine for processing said input data; B. storage means having a plurality of control instructions stored therein, said control instructions for enabling said logic means to perform said logical operations in a manner determined by said instructions; C. means for addressing said storage means to access said stored control instructions; D. means, included in said logic means, for executing said first routine in response to said accessed control instructions; E. means for suspending said execution of said first routine in order to execute said second routine; F. save means for storing an address associated with the last instruction of said first routine which was executed at the time of the suspension of the execution of said first routine, said address including a plurality of bits, each bit having either a first state or a second state; and G. means for restoring the operation of said first routine upon termination of the execution of said second routine including inverting means for inverting the state of one of said bits of said address stored in said save means to supply said means for addressing with an entry address, whereby said means for addressing accesses the instruction of said first routine which next follows said last instruction in order to restore said first routine to operation.