Editing Accumulator (computing) (section)

{{short description|Register in which intermediate arithmetic and logic results of a CPU are stored}}
[[File:Walther WSR-16 Inside the Machine.jpg|300px|thumb|Walther WSR-16 mechanical calculator. The row of digit-wheels in the carriage (at the front), is the Accumulator.]]
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In a [[computer]]'s [[central processing unit]] (CPU), the '''accumulator''' is a [[processor register|register]] in which intermediate [[arithmetic logic unit]] results are stored. 

Without a register like an accumulator, it would be necessary to write the result of each calculation (addition, multiplication, [[Bitwise operation#bit shifts|shift]], etc.) to [[Cache (computing)|cache]] or [[main memory]], perhaps only to be read right back again for use in the next operation. 

Accessing memory is slower than accessing a register like an accumulator because the technology used for the large main memory is slower (but cheaper) than that used for a register. Early electronic computer systems were often split into two groups, those with accumulators and those without.

Modern computer systems often have multiple general-purpose registers that can operate as accumulators, and the term is no longer as common as it once was. However, to simplify their design, a number of special-purpose processors still use a single accumulator.