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Cortex M and all ARM-developed cores prior to v7 are in-order CPUs, so they do not do branch prediction or speculative execution. Without branch prediction this
by sitharus 9y ago
Cortex M and all ARM-developed cores prior to v7 are in-order CPUs, so they do not do branch prediction or speculative execution. Without branch prediction this kind of issue cannot exist.
- rayiner 9y agoIn-order CPUs (e.g. Pentium 1, older Atom and ARM chips, POWER 6) perform branch prediction and speculative execution. They'll predict the branch and start speculatively decoding and executing instructions from the predicted target, then flush the pipeline if there was a misprediction. What they won't do is execute past an instruction that has an unresolved data dependency.
- sitharus 9y agoYou're right, I was conflating two things. It looks like no in-order ARM cores have branch prediction though.