Date: Thu, 26 Jun 1997 14:27:10 -0700 (PDT)
Message-Id: <199706262127.OAA25660@adit.ap.net>
Mime-Version: 1.0
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To: markoliv AT mercury DOT kosone DOT com
From: Nate Eldredge <eldredge AT ap DOT net>
Subject: Re: can you answer this
Cc: djgpp AT delorie DOT com
Precedence: bulk

>	Ok it's a great compiler but i don't know what's going on. First of all I
>don't really understand protected mode programming. The first question is,
>how do i change the video mode. I have always used inline assembler like
>this
> [deleted]
>If i understand (and i don't think i do) , cwsdpmi will slam the machine
>into real mode, perform the operation and exit. Could someone please
>straighten me out on this? If you can point me to resources that would be
>great but it would be alot better if you mailed me or
>posted to this group.

I suggest you have a look at the docs for the function __dpmi_int. This is
the preferred way to simulate real-mode interrupts.

>	Ok, next question	-	how do i write to video memory [deleted]

The preferred way to do _this_ is the so-called "farptr" functions. Look
them up in the docs. Basically, what you do is use selector _dos_ds() and
offset (0xA0000 (note- 4 "0"s) plus the offset into video memory). This is
also mentioned in the FAQ.

>	Ok, one more question. I am sure everyone asks someone this question
>sometime. I have an interrupt handler that drives the
>keyboard. I am sure that this won't work the same way. Could someone please
>tell me how to install an interrupt handler.	Ok, to 
>drive the mouse, i just poll interrupt table 0x33 - will this work in the
>same way? I am also pretty sure that my sound card can't be programmed in
>the same way - i use midpak and digpak	- but if anyone has any help on this
>i would appreciate it.

This, I believe, is covered in the FAQ as well. However, if you want to save
yourself a *LOT* of work, take a look at the Allegro library by Shawn
Hargreaves. It's at http://www.talula.demon.co.uk/ (the directory escapes
me, but you should be able to find it from there). It's a game library
containing very well-done facilities for graphics, keyboard, mouse, sound,
timer, "and much much more". :)

Hope this helps.


Nate Eldredge
eldredge AT ap DOT net