Xref: utzoo comp.sys.ibm.pc:53724 comp.sys.ibm.pc.programmer:2285
Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!cs.utexas.edu!uunet!psivax!torkil
From: torkil@psivax.UUCP (Torkil Hammer)
Newsgroups: comp.sys.ibm.pc,comp.sys.ibm.pc.programmer
Subject: Re: VGA standard (and Turbo C)
Message-ID: <3439@psivax.UUCP>
Date: 6 Jul 90 00:38:04 GMT
References: <13360@megatest.UUCP> <1990Jun29.194631.29214@amd.com>
Organization: Pacesetter Systems Inc., Sylmar, CA
Lines: 32

In article <1990Jun29.194631.29214@amd.com> phil@pepsi.amd.com (Phil Ngai) writes:
# mode (640x480). You have to go down to 320x200 to get 256 colors.
# The cloners provided extended resolution modes, and they all did
# it in a different way. 640x480x256 is a non-standard mode. CSHOW
# does it by having drivers for each different board. I assume that
# Borland did not provide support for 320x200x256 mode, or the
# structure to allow drivers for extended VGA modes.

The standard BGI drivers support up to VGA mode 12 (16 colors).
So it is correct that Borland did not provide support for 256 colors.

However, you can get a VGA mode 13 (320x200x256) BGI driver from SIMTEL.
I have used it with TC 2.0 and an ATI Wonder card, and it works.
There may be subtle differences between the way various VGA cards must
be programmed to use the 256 colors.  At least, the ATI card is quirky.

Also, the TC 2.0 supports super VGA modes as long as you have the BGI driver.
This will depend on mode and card.  I have used 800x600x256 and
1024x768x16 on the 512 kb ATI/multisync monitor combination, and while
some modes are slow, they work.

So, while the mode 13 driver should work (with allowance for quirks)
on all VGA cards, the SVGA drivers are not interchangable.

BTW, the way of using user supplied BGI drivers is illogical, but it
is documented in bits and pieces.  One would think that you install the
driver and select mode later, but you install the driver in the desired
mode and if you want to change mode later you must re-install.  It does not
take text string pointers, either.  You must use the text string
directly in the install function.

Torkil Hammer