Preventing CGA revisionist history

Jim Leonard trixter at oldskool.org
Thu Jan 19 15:02:06 CST 2006


Stan Barr wrote:
> I thought that was only on the PCJr.  Anyway my notes say it's video
> mode 8.

On the PCjr, it is mode 8.  On the PC, you had to go through the 
textmode trickery I explained in my last post.

The advantage of the PCjr mode (and composite color mode on stock CGA, 
another 160x200 mode) is that there is no character/attribute waste: A 
single byte holds 2 pixels.  It was a great mode for games because the 
simplicity of pixel packing was fast:

mov al,pixel1
mov cl,4
shl al,cl
or  al,pixel2

Only MCGA 320x200x256 was faster.
-- 
Jim Leonard (trixter at oldskool.org)            http://www.oldskool.org/
Help our electronic games project:           http://www.mobygames.com/
Or check out some trippy MindCandy at     http://www.mindcandydvd.com/
A child borne of the home computer wars: http://trixter.wordpress.com/



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