Instruction prefetch

A technique which attempts to minimise the time a processor spends waiting for instructions to be fetched from memory. Instructions following the one currently being executed are loaded into a prefetch queue when the processor’s external bus is otherwise idle. If the processor executes a branch instruction or receives an interrupt then the queue must be flushed and reloaded from the new address.
Instruction prefetch is often combined with pipelining in an attempt to keep the pipeline busy.
By 1995 most processors used prefetching, e.g. Motorola 680×0, Intel 80×86.
[First processors using prefetch?]


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