Retidy, removing align=left from headings and empty paragraphs

11-03.html

@@ -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="11-02.html">Previous</a></td>
+        <td>
+          <a href="11-02.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="11-04.html">Next</a></td>
+        <td>
+          <a href="11-04.html">Next</a>
+        </td>
       </tr>
     </table>
   </center>
 
-  <p><br /></p>
-
   <p>In short, a close relative of our old friend the 8-bit bus cycle-eater&mdash;the system memory wait state cycle-eater&mdash;haunts us still on all but zero-wait-state 286 and 386 computers, and that means that the prefetch queue cycle-eater is alive and well. (The system memory wait state cycle-eater isn&rsquo;t really a new cycle-eater, but rather a variant of the general wait state cycle-eater, of which the display adapter cycle-eater is yet another variant.) While the 286 in the AT can fetch instructions much faster than can the 8088 in the PC, it can execute those instructions faster still.</p>
 
   <p>The picture is less clear in the 386 world since there are so many different memory architectures, but similar problems can occur in any computer built around a 286 or 386. The prefetch queue cycle-eater is even a factor&mdash;albeit a lesser one&mdash;on zero-wait-state machines, both because branching empties the queue and because some instructions can outrun even zero&mdash;5 cycles longer than the official execution time.)</p>
@@ -128,22 +131,26 @@ Skip:
 
   <p>The data alignment cycle-eater has intriguing implications for speeding up 286/386 code. The expenditure of a little care and a few bytes to make sure that word-sized variables and memory blocks are word-aligned can literally double the performance of certain code running on the 286. Even if it doesn&rsquo;t double performance, word alignment usually helps and never hurts.</p>
 
-  <h4 align="left" id="Heading8">Code Alignment</h4>
+  <h4 id="Heading8">Code Alignment</h4>
 
   <p>Lack of word alignment can also interfere with instruction fetching on the 286, although not to the extent that it interferes with access to word-sized memory variables. The 286 prefetches instructions a word at a time; even if a given instruction doesn&rsquo;t begin at an even address, the 286 simply fetches the first byte of that instruction at the same time that it fetches the last byte of the previous instruction, as shown in Figure 11.2, then separates the bytes internally. That means that in most cases, instructions run just as fast whether they&rsquo;re word-aligned or not.</p>
 
   <p>There is, however, a non-word-alignment penalty on <i>branches</i> to odd addresses. On a branch to an odd address, the 286 is only able to fetch 1 useful byte with the first instruction fetch following the branch, as shown in Figure 11.3. In other words, lack of word alignment of the target instruction for any branch effectively cuts the instruction-fetching power of the 286 in half for the first instruction fetch after that branch. While that may not sound like much, you&rsquo;d be surprised at what it can do to tight loops; in fact, a brief story is in order.</p>
 
-  <p><br /></p>
-
   <center>
     <table border="1">
       <tr>
-        <td><a href="11-02.html">Previous</a></td>
+        <td>
+          <a href="11-02.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="11-04.html">Next</a></td>
+        <td>
+          <a href="11-04.html">Next</a>
+        </td>
       </tr>
     </table>
   </center>