The Intel 8088 and 8086 Processor’s Instruction Prefetch Circuitry

Cache prefetching is what allows processors to have data and/or instructions ready for use in a fast local cache rather than having to wait for a fetch request to trickle through to system RAM and back again. The Intel 8088  (and its big brother 8086) processor was among the first microprocessors to implement (instruction) prefetching in hardware, which [Ken Shirriff] has analyzed based on die images of this famous processor. This follows last year’s deep-dive into the 8086’s prefetching hardware, with (unsurprisingly) many similarities between these two microprocessors, as well as a few differences that are mostly due to the 8088’s cut-down 8-bit data bus.

This is a companion discussion topic for the original entry at