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Process and apparatus employing microprogrammed control commands for transferring information between a control processor and communications channels

  • US 4,325,119 A
  • Filed: 01/19/1977
  • Issued: 04/13/1982
  • Est. Priority Date: 01/19/1977
  • Status: Expired due to Term
First Claim
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1. In a data processing system including a main memory and a plurality of communication channels, said system having a central processing unit and a microprogrammed communication processor including a control element having a program memory storing microprogram instructions to enable said processor to control the transfer of data between said main memory and the other elements of said system, including said central processing unit and said communication channels, a machine implemented process in which said processor is controlled by said stored microprogram instructions to perform the method steps of:

  • A. determining whether said central processing unit has issued a control instruction to said processor;

    B. executing said control instruction if said step of determining indicates that said control instruction has been issued;

    C. repeating said steps of determining and executing until said step of determining indicates that said control instruction is not presently issued;

    D. determining, if no control instruction is detected during step A, whether one of said channels requires servicing;

    E. servicing a said channel requiring servicing if said last-mentioned step of determining indicates such service requirement;

    F. repeating said steps of determining, executing, repeating, determining, and servicing until a determination is made that a said channel does not require servicing;

    G. accessing control commands associated with a first said communication channel if there is no indication that a channel requires servicing;

    H. servicing said first channel if its said control commands indicate that the execution of said control commands is required;

    I. repeating said first step of determining and the further steps following said first step of determining until said step of accessing is entered again;

    J. repeating said step of accessing for a second said channel;

    K. repeating said second mentioned step of servicing for said second said channel; and

    L. reentering said first step of determining.

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