From:	SerDevian <scriven AT CS DOT ColoState DOT edu>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: Help: Keyboard interrupt
Date:	Thu, 23 Jan 1997 10:27:36 -0700
Organization:	XYZZ Software Co.
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Message-ID:	<32E79F88.167E@CS.ColoState.edu>
References:	<854022514 DOT 613673 AT red DOT parallax DOT co DOT uk>
NNTP-Posting-Host:	miro.vis.colostate.edu
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To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

John Eccleston wrote:
> Could someone please give me some pointers as to what I am doing wrong
> with this interrupt handler for the keyboard.

If it helps, look at the keyboard handler on my page.  You might find
your problem by comparing source.

> How would I get hold of the scancode for the key within the
> function my_handler?

I just use the lower 8 bits of the keypress value sent from the
keyboard.  Values from 0-127 indicate that a key was pressed, and values
from 128-255 mean a key was released.

> Is it OK to write an interrupt handler in C if you lock the code and
> data?  I know the FAQ says to write it in assembler but it mentions nothing
> about _go32_dpmi_lock_ functions.

Yes, you can do that.  You should lock your code and data even if you
use assembly, though.  Lock everything the handler can possibly
touch...  :)

I wouldn't recommend using C to write a handler that needs to be *fast*,
but it should be easily fast enough for a keyboard handler.


-- Yamaha / XYZZ          "May farce the with be you."
mailto:scriven AT CS DOT ColoState DOT edu          
mailto:scriven AT VIS DOT ColoState DOT edu
http://www.vis.colostate.edu/~scriven/

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