Misc/abrash-black-book
Watch
1
0
Fork
You've already forked abrash-black-book
 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

Retidy, removing align=left from headings and empty paragraphs

Browse source
This commit is contained in:
James Gregory 2013-12-30 15:37:13 +11:00
commit a96a114403
362 changed files with 8472 additions and 5040 deletions
Download patch file Download diff file Expand all files Collapse all files

33
16-06.html
View file

@ -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="16-05.html">Previous</a></td>
<td>
<a href="16-05.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="16-07.html">Next</a></td>
<td>
<a href="16-07.html">Next</a>
</td>
</tr>
</table>
</center>
<p><br /></p>
<h3 id="Heading9">Levels of Optimization</h3>
<p>Three levels of optimization were evident in the word-counting entries I received in response to my challenge. I&rsquo;d briefly describe them as &ldquo;fine-tuning,&rdquo; &ldquo;new perspective,&rdquo; and &ldquo;table-driven state machine.&rdquo; The latter categories produce faster code, but, by the same token, they are harder to design, harder to implement, and more difficult to understand, so they&rsquo;re suitable for only the most demanding applications. (Heck, I don&rsquo;t even guarantee that David Stafford&rsquo;s entry works perfectly, although, knowing him, it probably does; the more complex and cryptic the code, the greater the chance for obscure bugs.)</p>
@ -42,7 +45,7 @@
</tr>
</table>
<h4 align="left" id="Heading10">Optimization Level 1: Good Code</h4>
<h4 id="Heading10">Optimization Level 1: Good Code</h4>
<p>The first level of optimization involves fine-tuning and clever use of the instruction set. The basic framework is still the same as my code (which in turn is basically the same as that of the original C code), but that framework is implemented more efficiently.</p>
@ -56,16 +59,20 @@
<p>Listing 16.6, contributed by Willem Clements, of Granada, Spain, illustrates a variety of level 1 optimizations: the two-loop approach, the use of a 16- rather than 32-bit counter, and the use of <b>LODSW</b> . Together, these optimizations made Willem&rsquo;s code nearly twice as fast as mine in Listing 16.4. A few details could stand improvement; for example, <b>AND AX,AX</b> is a shorter way to test for zero than <b>CMP AX,0</b> , and <b>ALIGN 2</b> could be used. Nonetheless, this is good code, and it&rsquo;s also fairly compact and reasonably easy to understand. In short, this is an excellent example of how an hour or so of hand-optimization might accomplish significantly improved performance at a reasonable cost in complexity and time. This level of optimization is adequate for most purposes (and, in truth, is beyond the abilities of most programmers).</p>
<p><br /></p>
<center>
<table border="1">
<tr>
<td><a href="16-05.html">Previous</a></td>
<td>
<a href="16-05.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="16-07.html">Next</a></td>
<td>
<a href="16-07.html">Next</a>
</td>
</tr>
</table>
</center>