Remove colour attributes from body and strip most of the font tags out

03-04.html

@@ -24,7 +24,7 @@
 <!--CHAPTER=03//-->
 <!--PAGES=045-048//-->
 <!--UNASSIGNED1//-->
-<!--UNASSIGNED2//--></HEAD><BODY LINK=#0000FF ALINK=#000099 VLINK=#0000FF BGCOLOR=#FFFFFF>
+<!--UNASSIGNED2//--></HEAD><body>
 
 <CENTER>
 <TABLE BORDER>
@@ -43,12 +43,12 @@
 <P>Potentially far greater inaccuracy can be incurred by timing code that takes longer than about 110 ms to execute. Recall that all interrupts, including the timer interrupt, are disabled while timing code with the Zen timer. The 8259 interrupt controller is capable of remembering at most one pending timer interrupt, so all timer interrupts after the first one during any given Zen timing interval are ignored. Consequently, if a timing interval exceeds 54.9 ms, the system clock effectively stops 54.9 ms after the timing interval starts and doesn&rsquo;t restart until the timing interval ends, losing time all the while.</P>
 <P>The effects on the system time of the Zen timer aren&rsquo;t a matter for great concern, as they are temporary, lasting only until the next warm or cold boot. System that have batteryclocks, (AT-style machines; that is, virtually all machines in common use) automatically reset the correct time whenever the computer is booted, and systems without battery-clocks prompt for the correct date and time when booted. Also,repeated use of the Zen timer usually makes the system clock slow by at most a total of a few seconds, unless code that takes much longer than 54 ms to run is timed (in which case the Zen timer will notify you that the code is too long to time).</P>
 <P>Nonetheless, it&rsquo;s a good idea to reboot your computer at the end of each session with the Zen timer in order to make sure that the system clock is correct.</P>
-<H3><A NAME="Heading8"></A><FONT COLOR="#000077">Stopping the Zen Timer</FONT></H3>
+<H3><A NAME="Heading8"></A>Stopping the Zen Timer</H3>
 <P>At some point after <B>ZTimerOn</B> is called, <B>ZTimerOff</B> must always be called to mark the end of the timing interval. <B>ZTimerOff</B> saves the context of the calling program, latches and reads the timer 0 count, converts that count from the countdown value that the timer maintains to the number of counts elapsed since <B>ZTimerOn</B> was called, and stores the result. Immediately after latching the timer 0 count&mdash;and before enabling interrupts&mdash;<B>ZTimerOff</B> checks the 8259 interrupt controller to see if there is a pending timer interrupt, setting a flag to mark that the timer overflowed if there is indeed a pending timer interrupt.</P>
 <P>After that, <B>ZTimerOff</B> executes just the overhead code of <B>ZTimerOn</B> and <B>ZTimerOff</B> 16 times, and averages and saves the results in order to determine how many of the counts in the timing result just obtained were incurred by the overhead of the Zen timer rather than by the code being timed.</P>
 <P>Finally, <B>ZTimerOff</B> restores the context of the calling program, including the state of the interrupt flag that was in effect when <B>ZTimerOn</B> was called to start timing, and returns.</P>
 <P>One interesting aspect of <B>ZTimerOff</B> is the manner in which timer 0 is stopped in order to read the timer count. We don&rsquo;t actually have to stop timer 0 to read the count; the 8253 provides a special latched read feature for the specific purpose of reading the count while a time is running. (That&rsquo;s a good thing, too; we&rsquo;ve no documented way to stop timer 0 if we wanted to, since its gate input isn&rsquo;t connected. Later in this chapter, though, we&rsquo;ll see that timer 0 can be stopped after all.) We simply tell the 8253 to latch the current count, and the 8253 does so without breaking stride.</P>
-<H3><A NAME="Heading9"></A><FONT COLOR="#000077">Reporting Timing Results</FONT></H3>
+<H3><A NAME="Heading9"></A>Reporting Timing Results</H3>
 <P><B>ZTimerReport</B> may be called to display timing results at any time after both <B>ZTimerOn</B> and <B>ZTimerOff</B> have been called. <B>ZTimerReport</B> first checks to see whether the timer overflowed (counted down to 0 and turned over) before <B>ZTimerOff</B> was called; if overflow did occur, <B>ZTimerOff</B> prints a message to that effect and returns. Otherwise, <B>ZTimerReport</B> subtracts the reference count (representing the overhead of the Zen timer) from the count measured between the calls to <B>ZTimerOn</B> and <B>ZTimerOff</B>, converts the result from timer counts to microseconds, and prints the resulting time in microseconds to the standard output.</P>
 <P>Note that <B>ZTimerReport</B> need not be called immediately after <B>ZTimerOff</B>. In fact, after a given call to <B>ZTimerOff, ZTimerReport</B> can be called at any time right up until the next call to <B>ZTimerOn</B>.</P>
 <P>You may want to use the Zen timer to measure several portions of a program while it executes normally, in which case it may not be desirable to have the text printed by <B>ZTimerReport</B> interfere with the program&rsquo;s normal display. There are many ways to deal with this. One approach is removal of the invocations of the DOS print string function (INT 21H with AH equal to 9) from <B>ZTimerReport</B>, instead running the program under a debugger that supports screen flipping (such as Turbo Debugger or CodeView), placing a breakpoint at the start of <B>ZTimerReport</B>, and directly observing the count in microseconds as <B>ZTimerReport</B> calculates it.</P>
@@ -69,7 +69,7 @@
 
 <hr width="90%" size="1" noshade>
 <div align="center">
-<font face="Verdana,sans-serif" size="1">Graphics Programming Black Book &copy; 2001 Michael Abrash</font>
+Graphics Programming Black Book &copy; 2001 Michael Abrash
 </div>
 <!-- all of the reference materials (books) have the footer and subfoot reveresed -->
 <!-- reference_subfoot = footer -->