vertical encoding

1 definition found

vertical encoding - Free On-line Dictionary of Computing (26 May 2007) :

  vertical encoding
  
     <processor> An instruction set where a field (a bit or group
     of bits) of the instruction word is decoded (either by
     hard-wired logic or microcode) to generate signals to
     control the functional units, as opposed to horizontal encoding
      where the instruction word bits are used as the
     control signals directly.
  
     With vertical encoding, which combinations of signals and
     operations are possible is dictated by the decoding logic; the
     instruction field can only select one of these preprogrammed
     combinations.  This has the advantage that many control
     signals can be generated based on only a few instruction word
     bits and only valid combinations of control signals can be
     generated, e.g. only one source driving a bus at once.  An
     instruction set may use a mixture of horizontal and vertical
     encoding within each instruction.
  
     (1995-04-23)