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

Deduped images

Browse source
This commit is contained in:
James Gregory 2013-12-30 12:25:34 +11:00
commit 9e52de9586
233 changed files with 128 additions and 128 deletions
Download patch file Download diff file Expand all files Collapse all files

2
44-04.html
View file

@ -75,7 +75,7 @@ mov byte ptr es:[di],0ffh
<!-- END CODE SNIP //-->
<TABLE WIDTH="100%">
<TR>
<TD VALIGN="TOP" ALIGN="LEFT" WIDTH="5%"><IMG SRC="images/44-01i.jpg"><TD VALIGN="TOP" ALIGN="LEFT" WIDTH="95%"><I><SMALL>If you&#146;re familiar with VGA programming, you&#146;re no doubt aware that everything that can be done with write mode 3 can also be accomplished in write mode 0 or write mode 2 by using the Bit Mask register. However, setting the Bit Mask register requires at least one <B>OUT</B> per byte written, in addition to the read and write of display memory, and <B>OUT</B>s are often slower than display memory accesses, especially on 386s and 486s. One of the great virtues of write mode 3 is that it requires virtually no <B>OUT</B>s and is therefore substantially faster for masking than the other write modes.</SMALL></I>
<TD VALIGN="TOP" ALIGN="LEFT" WIDTH="5%"><IMG SRC="images/i.jpg"><TD VALIGN="TOP" ALIGN="LEFT" WIDTH="95%"><I><SMALL>If you&#146;re familiar with VGA programming, you&#146;re no doubt aware that everything that can be done with write mode 3 can also be accomplished in write mode 0 or write mode 2 by using the Bit Mask register. However, setting the Bit Mask register requires at least one <B>OUT</B> per byte written, in addition to the read and write of display memory, and <B>OUT</B>s are often slower than display memory accesses, especially on 386s and 486s. One of the great virtues of write mode 3 is that it requires virtually no <B>OUT</B>s and is therefore substantially faster for masking than the other write modes.</SMALL></I>
</TABLE>
<P>In short, write mode 3 is a good choice for single-color drawing that modifies individual pixels within display memory bytes. Not coincidentally, the sample application draws only single-color objects within the animation area; this allows write mode 3 to be used for all drawing, in keeping with our desire for speedy screen updates.
</P>