Re: 640*480 memory modes
The Reaper wrote:
>
> Loo woo seob, anything you can send me about mode 18 or the other modes you
> were talking about would be appreciated.
Lee, May I have a copy of the svga library too?
> And, yes Pete, Mode 18 only has 16 colors. Sigh... 
Did I say something?
It was Daniel Berstein that pointed out the number of colors.
Here's what I know about mode 18, 640x480x16. Video memory is set up
like 8 pixels per byte. Each bit written to memory is copied to any
combination of the 4 video planes (red, green, blue, intensity). Which
planes bits are copied to is determined by the video map mask register.
So to write a magenta pixel to the screen set the map mask to 5 and
write a 1 to memory. If the memory isn't already known to be 0's then
you have to not the map mask register and write a 0 to memory. But
there are other write modes that the video processor can do, like one
optimized for bit-block-transfers and one for single pixel methods. In
my opinion, 16-color modes are not worth the headache of switching
planes and manipulating bits and all that. Sixteen-color routines would
have to be coded in machine language to be fast enough for any real
use. So I suggest sticking with SVGA.
Happy Coding,
--
_____ _____ _____
________ /\ \ /\ \ /\ \
/ \ \ / \____\ / \____\ / \____\
/ _ \____\ / / ___/_ / /____/ / / ___/_
/ / \ [___] / / /\____\ / \ \ / / /\____\
\ \_/ / / \ \/ / ___/_\ \ \ \ \/ / ___/_
\ /____/ \ / /\ \\/\ \ \ \ / /\ \
\ \ \ \ \/ \____\ \ \ \ \ \/ \____\
\ \ \ \ / / \ \____\ \ / /
\ \____\ \ / / \ / / \ / /
\ / / \ / / \/____/ \ / /
\/____/ \/____/xseal at harborside.com\/____/
|
Not Categorized, Please Help
|
|
