operation code

2 definitions found

operation code - WordNet (r) 2.1 (2005) :

  operation code
      n 1: the portion of a set of operation descriptions that
           specifies the operation to be performed; the set of
           operations in a computer [syn: operation code, order code
           ]

operation code - Free On-line Dictionary of Computing (26 May 2007) :

  operation code
  
     <programming> (Or "op code") The part or parts of a machine language
      instruction which determines what kind of action the
     computer should take, e.g. add, jump, load, store.  In any
     particular instruction set certain fixed bit positions
     within the instruction word contain the op code, others give
     parameters such as the addresses or registers involved.
     For example, in a 32-bit instruction the most significant
     eight bits might be the op code giving 256 possible
     operations.
  
     For some instruction sets, certain values in the fixed bit
     positions may select a group of operations and the exact
     operation may depend on other bits within instruction word or
     subsequent words.
  
     When programming in assembly language, the op code is
     represented by a readable name called an instruction mnemonic
     .
  
     (1997-02-14)