dictionary definitions for "accumulator"


From WordNet (r) 2.0 (August 2003) [wn]:

  accumulator
      n 1: a person who is employed to collect payments (as for rent or
           taxes) [syn: collector, gatherer]
      2: a voltaic battery that stores electric charge [syn: {storage
         battery}]
      3: (computer science) a register that has a built-in adder that
         adds an input number to the contents of the accumulator
         [syn: accumulator register]

From The Collaborative International Dictionary of English v.0.48 [gcide]:

  Accumulator \Ac*cu"mu*la`tor\, n. [L.]
     1. One who, or that which, accumulates, collects, or amasses.
        [1913 Webster]
  
     2. (Mech.) An apparatus by means of which energy or power can
        be stored, such as the cylinder or tank for storing water
        for hydraulic elevators, the secondary or storage battery
        used for accumulating the energy of electrical charges,
        etc.
        [1913 Webster]
  
     3. A system of elastic springs for relieving the strain upon
        a rope, as in deep-sea dredging.
        [1913 Webster]

From The Free On-line Dictionary of Computing (19 Sep 2003) [foldoc]:

  accumulator
  
     <processor> In a central processing unit, a register in
     which intermediate results are stored.  Without an
     accumulator, it would be necessary to write the result of each
     calculation (addition, multiplication, shift, etc.) to {main
     memory} and read them back.  Access to main memory is slower
     than access to the accumulator which usually has direct paths
     to and from the arithmetic and logic unit (ALU).
  
     The canonical example is summing a list of numbers.  The
     accumulator is set to zero initially, each number in turn is
     added to the value in the accumulator and only when all
     numbers have been added is the result written to main memory.
  
     Modern CPUs usually have many registers, all or many of which
     can be used as accumulators.  For this reason, the term
     "accumulator" is somewhat archaic.  Use of it as a synonym for
     "register" is a fairly reliable indication that the user has
     been around for quite a while and/or that the architecture
     under discussion is quite old.  The term in full is almost
     never used of microprocessor registers, for example, though
     symbolic names for arithmetic registers beginning in "A"
     derive from historical use of the term "accumulator" (and not,
     actually, from "arithmetic").  Confusingly, though, an "A"
     register name prefix may also stand for "address", as for
     example on the Motorola 680x0 family.
  
     2. <programming> A register, memory location or variable being
     used for arithmetic or logic (as opposed to addressing or a
     loop index), especially one being used to accumulate a sum or
     count of many items.  This use is in context of a particular
     routine or stretch of code.  "The FOOBAZ routine uses A3 as an
     accumulator."
  
     [Jargon File]
  
     (1999-04-20)
  

From Jargon File (4.4.4, 14 Aug 2003) [jargon]:

  accumulator
   n. obs.
  
     1. Archaic term for a register. On-line use of it as a synonym for
     register is a fairly reliable indication that the user has been
     around for quite a while and/or that the architecture under
     discussion is quite old. The term in full is almost never used of
     microprocessor registers, for example, though symbolic names for
     arithmetic registers beginning in `A' derive from historical use of
     the term accumulator (and not, actually, from `arithmetic').
     Confusingly, though, an `A' register name prefix may also stand for
     address, as for example on the Motorola 680x0 family.
  
     2. A register being used for arithmetic or logic (as opposed to
     addressing or a loop index), especially one being used to accumulate
     a sum or count of many items. This use is in context of a particular
     routine or stretch of code. "The FOOBAZ routine uses A3 as an
     accumulator."
  
     3. One's in-basket (esp. among old-timers who might use sense 1).
     "You want this reviewed? Sure, just put it in the accumulator." (See
     stack.)
  


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