delorie.com/archives/browse.cgi   search  
Mail Archives: djgpp/2000/01/05/08:25:35

Message-ID: <F77915E7F086D31197F4009027CC81C917B709@probe-2.as-london.acclaim.com>
From: Shawn Hargreaves <SHargreaves AT acclaimstudios DOT co DOT uk>
To: djgpp AT delorie DOT com
Subject: Re: VBE 1.2 -- question
Date: Wed, 5 Jan 2000 12:56:10 -0000
MIME-Version: 1.0
X-Mailer: Internet Mail Service (5.5.2650.21)
Reply-To: djgpp AT delorie DOT com

sl writes:
> I was wondering how video-page scrolling and flipping works.
[...]
> I'm basically asking about the memory model being used to 
> support these two features

It's entirely up to you. Video memory is just that: a large
area of memory. The display start address tells the hardware
what location in that memory it should start at when displaying
each frame, and the display width tells the hardware how many
bytes to skip past when moving from one scanline to the next.
You use VESA calls to control these values, and then do whatever
you like with the rest: it's up to you whether to treat this
memory as one large 2d area, or many smaller regions, or
anything else that you can come up with.


	Shawn Hargreaves.

- Raw text -


  webmaster     delorie software   privacy  
  Copyright © 2019   by DJ Delorie     Updated Jul 2019