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From: jallen@netxcom.UUCP (John Allen)
Newsgroups: comp.sys.ibm.pc
Subject: Re: Silly EGA question, but...
Message-ID: <289@netxcom.UUCP>
Date: Mon, 2-Feb-87 18:07:04 EST
Article-I.D.: netxcom.289
Posted: Mon Feb  2 18:07:04 1987
Date-Received: Sat, 7-Feb-87 04:32:04 EST
References: <4602@watmath.UUCP> <651@uw-warp.UUCP>
Reply-To: jallen@netxcom.UUCP (John Allen)
Organization: NetExpress Communications Inc. Vienna, Va.
Lines: 33

In article <651@uw-warp.UUCP> tom@uw-warp.UUCP (Tom May) writes:
>In article <4602@watmath.UUCP>, daemon@watmath.UUCP writes:
>> I cant find in my limited documentation just HOW EXACTLY does one
>> write/make graphics/colours on an AT EGA console. (dos3.x)
>> BASIC has its keywords for doing graphics things, but how do generic
>> programs do things the hard way?
>> 
>>           - Ken Dykes
>
>I used the video interrupt, INT 10h, to write pixels on the EGA from assembly
>[deleted]   You also have to use
>INT 10h to get the card into the correct mode.  I think you get some
>documentation with it that tells about the modes, otherwise you'll have to
>resort to trial and error.-- 
>Tom May.	uw-beaver!uw-nsr!uw-warp!tom


I'd sure hate to use the "trial and error" method.  I've got 3 EGA clones
that came with little or no programmer documentation (caveat buyer).
Since I wanted to write stuff that would run on "most" EGAs, this was OK.
I got the IBM PC Technical Reference - the one with the adapters in it -
and used the EGA BIOS listing.  This also delivered a notable side effect:
Of the three EGA clones available to me for development and testing, none
behaved according to the IBM BIOS specs (in certain cases), and each
behaved differently in others.


John Allen
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