Use markdown style lists
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11-03.md
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11-03.md
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@ -29,22 +29,22 @@ outrun even zero—5 cycles longer than the official execution time.)
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To summarize:
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- Memory-accessing instructions don't run at their official speeds on
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* Memory-accessing instructions don't run at their official speeds on
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non-zero-wait-state 286/386 computers.
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- The prefetch queue cycle-eater reduces performance on 286/386
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* The prefetch queue cycle-eater reduces performance on 286/386
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computers, particularly when non-zero-wait-state memory is used.
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- Branches often execute at less than their rated speeds on the 286
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* Branches often execute at less than their rated speeds on the 286
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and 386 since the prefetch queue is emptied.
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- The extent to which the prefetch queue and wait states affect
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* The extent to which the prefetch queue and wait states affect
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performance varies from one 286/386 computer to another, making
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precise optimization impossible.
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What's to be learned from all this? Several things:
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- Keep your instructions short.
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- Keep it in the registers; avoid memory, since memory generally can't
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* Keep your instructions short.
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* Keep it in the registers; avoid memory, since memory generally can't
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keep up with the processor.
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- Don't jump.
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* Don't jump.
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Of course, those are exactly the rules that apply to 8088 optimization
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as well. Isn't it convenient that the same general rules apply across
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