Signature of ATT 6300 graphics
XMP12-M.CRIPPS
mcripps at mtuxo.UUCP
Fri Apr 22 07:09:54 AEST 1988
In article <682 at leah.Albany.Edu>, rds95 at leah.Albany.Edu (Robert Seals) writes:
> Yo,
> I'm using Turbo C 1.5 to write some purportedly portable (!?)
> programs that include some graphics. My version of TC does not
> autodetect a PC6300Plus adapter/screen as being a 6300, but a cga, even
> though it does support drawing in 6300 mode when initialized
> explicitly as being 6300.
>
> Zo, does anyone know what kind of signature to look for to try
> to identify an ATT as being ATT?
>
If all you're worried about is video, that's easy. Change the video mode
to 40h (the AT&T Hi-Res mode) and do a get video mode call
(int 10h, function 0fh) to see if it returns 40h.
Alternately, write something to 0b800:6000 and see if you can
read it back (the AT&T board has 32K of video memory, the CGA has 16K).
Using these methods, your routines can support *ALL* AT&T machines with the
non-standard video boards, without being ROM dependent.
The get video mode trick may return a false positive if other manufacturers
use 40h as a mode, but I'm not aware of any. The memory test may be true
on non-AT&T boards, but functionally the boards are probably the same, so
it wouldn't matter (The Sigma Color 400 is mapped the same as the AT&T, for
instance).
------------------------------------------------------------------------------
^ Michael J. Cripps
/ I \ AT&T Lincroft, NJ These opinions reflect none other
------- mtuxo!mcripps than myself.
/_|___|_\ (201) 576-2428
/|___|___|\
/___|___|___\ Have a nice day fnord.
-------------------------------------------------------------------------------
More information about the Comp.sys.att
mailing list