• DocumentCode
    1106391
  • Title

    Conditional Interpretation of Operation Codes

  • Author

    Foster, Caxton C. ; Gonter, Robert

  • Issue
    1
  • fYear
    1971
  • Firstpage
    108
  • Lastpage
    111
  • Abstract
    A method, called conditional interpretation, is proposed which will allow small computers to have as large a set of instructions as may be desired without using a large number of bits to hold the operation code. The method is based on the redundancy of machine language instruction sequences. Most machine language instructions have a limited number of "reasonable" successors. For example "load accumulator" hardly ever follows "enter accumulator." It turns out that if each instruction is allowed seven successors plus an "escape instruction," only about one out of every five instructions needs to be an "escape" to get to one of the less usual successors. Seventy-five percent of the time the desired "next instruction" is among the seven permitted successors. Since each instruction has its own, possibly unique, set of successors, the interpretation of the stored op-code is conditional upon the state of the machine.
  • Keywords
    Conditional decoding, instruction digrams, instructions sets, machine language redundancy, mini-computers, operation codes.; Banking; Computer aided instruction; Costs; Decoding; Floating-point arithmetic; Indexing; Instruction sets; Linear discriminant analysis; Microprogramming; Conditional decoding, instruction digrams, instructions sets, machine language redundancy, mini-computers, operation codes.;
  • fLanguage
    English
  • Journal_Title
    Computers, IEEE Transactions on
  • Publisher
    ieee
  • ISSN
    0018-9340
  • Type

    jour

  • DOI
    10.1109/T-C.1971.223091
  • Filename
    1671684