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Convert notes into blockquotes

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James Gregory 2013-12-31 11:06:31 +11:00
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@ -52,9 +52,10 @@ base+index addressing (**[EBX+EAX]**), which saves a cycle on the 386.
Second: Changing the instruction to **CMP [EAX],DH** saved 2 cycles—just
enough, by good fortune, to speed up the whole program by 5 percent.
------------------- ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
![](images/i.jpg) ***CMP reg,[mem]** takes 6 cycles on the 386, but **CMP [ mem ],reg** takes only 5 cycles; you should always perform**CMP** with the memory operand on the left on the 386.*
------------------- ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
> ![](images/i.jpg)
> **CMP reg,[mem]** takes 6 cycles on the 386, but **CMP [ mem ],reg**
> takes only 5 cycles; you should always perform**CMP** with the memory
> operand on the left on the 386.
(Granted, **CMP [*mem*],*reg*** is 1 cycle slower than **CMP
*reg*,[*mem*]** on the 286, and they're both the same on the 8088; in
@ -99,9 +100,10 @@ faster. Consider the incongruity of Terje's willingness to consider a 5
percent speedup significant in light of his later near-doubling of
performance.
------------------- --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
![](images/i.jpg) *Don't get stuck in the rut of instruction-by-instruction optimization. It's useful in key loops, but very often, a change in approach will work far greater wonders than any amount of cycle counting can.*
------------------- --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
> ![](images/i.jpg)
> Don't get stuck in the rut of instruction-by-instruction optimization.
> It's useful in key loops, but very often, a change in approach will work
> far greater wonders than any amount of cycle counting can.
By the way, Terje's WC50 program is a full-fledged counting program; it
counts characters, words, and lines, can handle multiple files, and lets