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Retidy, removing align=left from headings and empty paragraphs

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James Gregory 2013-12-30 15:37:13 +11:00
commit a96a114403
362 changed files with 8472 additions and 5040 deletions
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13-03.html
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@ -1,5 +1,4 @@
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
@ -19,17 +18,21 @@
<center>
<table border="1">
<tr>
<td><a href="13-02.html">Previous</a></td>
<td>
<a href="13-02.html">Previous</a>
</td>
<td><a href="index.html">Table of Contents</a></td>
<td>
<a href="index.html">Table of Contents</a>
</td>
<td><a href="13-04.html">Next</a></td>
<td>
<a href="13-04.html">Next</a>
</td>
</tr>
</table>
</center>
<p><br /></p>
<p>On the 386, <b>ROR</b> was the only way to split a 32-bit register into two 16-bit registers. On the 486, however, <b>BSWAP</b> can not only do the job, but can do it better, because <b>BSWAP</b> executes in just one cycle. <b>BSWAP</b> has the added benefit of not affecting any flags, unlike <b>ROR</b>. With <b>BSWAP</b>-based code like that in Listing 13.6, the upper 16 bits of a register can be accessed with only 2 cycles of overhead and without altering any flags, making the technique of packing two 16-bit registers into one 32-bit register much more useful.</p>
<p><b>LISTING 13.6 L13-6.ASM</b></p>
@ -89,16 +92,20 @@ mov dx,ax
<p>Again, this technique is advantageous <i>only</i> on a 486. It also doesn&rsquo;t apply to <b>RCL</b> and <b>RCR,</b> where you definitely want to use the 1-bit versions whenever you can, because the n-bit versions are horrendously slow. But if you&rsquo;re optimizing for the 486, these tidbits can save a few critical cycles&mdash;and Lord knows that if you&rsquo;re optimizing for the 486&mdash;that is, if you need even more performance than you get from unoptimized code on a 486&mdash;you almost certainly need all the speed you can get.</p>
<p><br /></p>
<center>
<table border="1">
<tr>
<td><a href="13-02.html">Previous</a></td>
<td>
<a href="13-02.html">Previous</a>
</td>
<td><a href="index.html">Table of Contents</a></td>
<td>
<a href="index.html">Table of Contents</a>
</td>
<td><a href="13-04.html">Next</a></td>
<td>
<a href="13-04.html">Next</a>
</td>
</tr>
</table>
</center>