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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 from "arithmetic" as is sometimes believed). Confusingly, though, an "A" register name prefix may also stand for "address", as for example on the Motorola 68000 family.

1 References

2 Other uses

• in computer 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 FOOBAR routine uses A3 as an accumulator."
• an apparatus by means of which energy or power can be stored, such as a rechargeable battery or an hydraulic accumulator.
• a type of bet.