Date: Wed, 9 Aug 1995 13:22:43 +0300 (IDT)
From: Eli Zaretskii <eliz AT is DOT elta DOT co DOT il>
To: Brendan Simon <brendan AT rdt DOT monash DOT edu DOT au>
Cc: djgpp AT sun DOT soe DOT clarkson DOT edu
Subject: Re: V2 interrupts


On Wed, 9 Aug 1995, Brendan Simon wrote:

> purposes.  I've played around with interrupts in v1.12m3 using a signal
> generator.  I was disappointed that the max frequency I could set was
> about 300-500 Hz before it crashed.  All the interrupt routine did was
> update a counter as in the timer interrupt example.
> This seemed extremly low.  Especially since I want to log 4 Channels at
> about 10-20kHz.
> 
> I hear that V2.0beta handles interrupts better.

v2.0 was seen to work with 10 KHz hardware interrupt frequency without 
crashing on a 486-DX/33.

> Do I still need to use the wrapper method to handle interrupts while in
> real mode.

In DPMI mode (the only mode v2.0 works) hardware interrupts are always 
reflected to protected mode first (although the reflection has a 
relatively high overhead), so if the above performance suits you, you 
don't have to bother about real-mode handler.

If you didn't already, I suggest you read Chapter 18 of the DJGPP FAQ 
list, especially section 18.7 there, which explains how to register 
hardware interrupt handlers; the part which speaks about DPMI mode is 
still valid under v2.0.