The Register File

Since numbers must first be fetched from storage before they can be added, we want our data storage space to be as fast as possible so that the operation can be carried out quickly. Since the ALU is the part of the processor that does the actual addition, we’d like to place the data storage as close as possible to the ALU so it can read the operands almost instantaneously. However, practical considerations, such as a CPU’s limited surface area, constrain the size of the storage area that we can stick next to the ALU. This means that in real life, most computers have a relatively small number of very fast data storage locations attached to the ALU. These storage locations are called registers, and the first x86 computers only ...

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