Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!killer!chasm
From: chasm@killer.DALLAS.TX.US (Charles Marslett)
Newsgroups: comp.sys.amiga
Subject: Re: EGA/VGA (was Re: Silver (was Re: Amiga 2000 has been swapped))
Summary: Then you get to the funny modes!
Message-ID: <5614@killer.DALLAS.TX.US>
Date: 24 Sep 88 13:41:17 GMT
References: <2@orbit.UUCP> <6908@well.UUCP>, 
Organization: The Unix(R) Connection, Dallas, Texas
Lines: 15

In article , mp1u+@andrew.cmu.edu (Michael Portuesi) writes:
> The way the problem with VGA was explained to me, it is possible to memory map
> the *first* bitplane of display.  Accessing any further bitplanes require the
> bogus gymnastics detailed . . .
> 
> Michael Portuesi / Information Technology Center / Carnegie Mellon University

Actually, in the 256 color modes (mode 0x13 in the IBMer, and several in the
better clone cards) the memory map is a 1-byte per pixel mode where I/O is
no longer necessary except to skip to other "pages" of video memory.  The
paging is necessary because IBM only allocated 128K for video memory and
an 800x640 resolution 256-color mode requires 512K.

Charles Marslett
chasm@killer.dallas.tx.us