Register

Processors have a small amount of very fast memory called registers that they use to hold data that they are currently working with.

They can only hold a tiny amount of data - usually just 32-64 bits (4-8 bytes) - but they are much faster than the main memory (RAM) and can be accessed much more quickly by the CPU.

They’re used to hold data that the CPU is currently processing, such as the operands for an maths operation, or the address of a memory location that the CPU is about to access.

You’ll see a lot more about registers if you do any assembly programming, because in assembly you have to manage the registers yourself, and you have to tell the CPU exactly which registers to use for what.

Common registers in the CPU

See processor registers for a list of the common registers that are found in most CPUs, and what they do!