Accumulator
from
The Collaborative International Dictionary of English v.0.48
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
Jargon File (4.4.4, 14 Aug 2003)
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}.)
from
The Free On-line Dictionary of Computing (8 July 2008)
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)
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