Accumulator (computing)

An accumulator is a register within the CPU, in the results of the arithmetic unit ( ALU) is stored. Most the accumulator is permanently connected to the second input of the ALU. Individual batteries are now playing almost exclusively in smaller microprocessors a role. Most of the 16 - or 32 -bit processors (or wider) to use a larger number of accumulators, which are then referred to as data register. See also: Akkumulatorrechner

Without an accumulator, it would be necessary for each result of a calculation (addition, multiplication, logic operation, etc.) to be stored in main memory and from there to load back into the CPU. The access to the accumulator, however, is much faster than a main store access, since this register is integrated with the ALU in the CPU.

Accumulators are used for the computation of dot products and in particular in digital signal processing using a DSP. For this purpose, the output of the multiplying unit is supplied to an input of the adder. The output of the adder is connected to a register, which in turn is connected to the second input of the adder. This accumulator circuit the sum of products is determined ( the scalar product ). This operation is also called multiply-accumulate.

Also in the program is a variable that contains intermediate results (eg in loops ), sometimes referred to as an accumulator.

• Computer Architecture