AMOS:Screenbase structure
Revision as of 03:21, 28 September 2007 by Spellcoder (talk | contribs) (email from AMOS-list (1993) about the structure at Screen Base)
Date: 26 May 93 19:56:00 EST
From: Andrew Church <95ACHURCH@vax.mbhs.edu>
Subject: Re: Screen Base
To: amos-list <amos-list@access.digex.net>
In case anyone's interested, here's all I've been able to find out
about the Screen Base structure:
Ofs | Item
----+-----------------------------------------------------
$00 | Bitplane 0 (active buffer of double-buffered screen)
$04 | Bitplane 1
$08 | Bitplane 2
$0C | Bitplane 3
$10 | Bitplane 4
$14 | Bitplane 5
$18 | Bitplane 0 (first buffer)
$1C | Bitplane 1
$20 | Bitplane 2
$24 | Bitplane 3
$28 | Bitplane 4
$2C | Bitplane 5
$30 | Bitplane 0 (second buffer)
$34 | Bitplane 1
$38 | Bitplane 2
$3C | Bitplane 3
$40 | Bitplane 4
$44 | Bitplane 5
$48 | Screen mode (value of BPLCON0 custom chip register)
$4A | ???
$4C | Width
$4E | Height
$50 | Depth
$52 | X hardware display position
$54 | Y hardware display position + $1000
| (actual position = Deek(Screen Base+$54)-$1000
$56 | Width of displayed area of screen in low-res pixels
| (2 hi-res pixels for each low-res pixel)
$58 | Height of displayed area of screen
$5A | X screen offset
$5C | Y screen offset
$5E | ???
$60 | ???
$62 | ???
$64 | Number of colors in screen (2^Depth)
$66 | Color 0
$68 | Color 1
: | :
: | :
$A4 | Color 31
--Andy Church
