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

Strip comments and inline ids onto h*

Browse source
This commit is contained in:
James Gregory 2013-12-30 15:11:04 +11:00
commit 0f5f617adb
362 changed files with 2519 additions and 6694 deletions
Download patch file Download diff file Expand all files Collapse all files

25
25-05.html
View file

@ -10,16 +10,9 @@
<meta name="vspubdate" content="07/01/97" />
<meta name="vscategory" content="Web and Software Development: Game Development,Web and Software Development: Graphics and Multimedia Development" />
<title>Michael Abrash's Graphics Programming Black Book Special Edition: VGA Data Machinery</title><!-- HEADER -->
<!-- Empty Reference Subhead -->
<!--ISBN=1576101746//-->
<!--TITLE=Michael Abrash's Graphics Programming Black Book Special Edition//-->
<!--AUTHOR=Michael Abrash//-->
<!--PUBLISHER=The Coriolis Group, Inc.//-->
<title>Michael Abrash's Graphics Programming Black Book Special Edition: VGA Data Machinery</title>
<meta name="chapter" content="25" />
<meta name="pages" content="474-478" />
<!--UNASSIGNED1//-->
<!--UNASSIGNED2//-->
</head>
<body>
@ -37,7 +30,7 @@
<p><br /></p>
<p><b>LISTING 25.3 L25-3.ASM</b></p><!-- CODE //-->
<p><b>LISTING 25.3 L25-3.ASM</b></p>
<pre>
; Program to illustrate operation of set/reset circuitry to force
; setting of memory that already contains data.
@ -147,15 +140,15 @@ HorzBarLoop:
start endp
cseg ends
end start
</pre><!-- END CODE //-->
</pre>
<h4 align="left"><a id="Heading7"></a>Manipulating Planes Individually</h4>
<h4 align="left" id="Heading7">Manipulating Planes Individually</h4>
<p>Listing 25.4 illustrates the use of set/reset to control only some, rather than all, planes. Here, the set/reset circuitry forces plane 2 to 1 and planes 0 and 3 to 0. Because bit 1 of the Enable Set/Reset register is 0, however, set/reset does not affect plane 1; the CPU data goes unchanged to the plane 1 ALU. Consequently, the CPU data can be used to control the value written to plane 1. Given the settings of the other three planes, this means that each bit of CPU data that is 1 generates a brown pixel, and each bit that is 0 generates a red pixel. Writing alternating bytes of 07H and 0E0H, then, creates a vertically striped pattern of brown and red.</p>
<p>In Listing 25.4, note that the vertical bars are 10 and 6 bytes wide, and do not start on byte boundaries. Although set/reset replaces an entire byte of CPU data for a plane, the combination of set/reset for some planes and CPU data for other planes, as in the example above, can be used to control individual pixels.</p>
<p><b>LISTING 25.4 L25-4.ASM</b></p><!-- CODE //-->
<p><b>LISTING 25.4 L25-4.ASM</b></p>
<pre>
; Program to illustrate operation of set/reset circuitry in conjunction
; with CPU data to modify setting of memory that already contains data.
@ -265,7 +258,7 @@ HorzBarLoop:
start endp
cseg ends
end start
</pre><!-- END CODE //-->
</pre>
<p><br /></p>
@ -284,10 +277,6 @@ cseg ends
<div align="center">
Graphics Programming Black Book &copy; 2001 Michael Abrash
</div><!-- all of the reference materials (books) have the footer and subfoot reveresed -->
<!-- reference_subfoot = footer -->
<!-- reference_footer = subfoot -->
<!-- BEGIN SUB FOOTER -->
<!-- END FOOTER -->
</div>
</body>
</html>