Date: Sun, 17 Nov 1996 10:15:42 +0200 (IST)
From: Eli Zaretskii <eliz AT is DOT elta DOT co DOT il>
To: Glen Miner <gminer AT Newbridge DOT COM>
Cc: djgpp AT delorie DOT com
Subject: Re: Calling 16bit interrupts
In-Reply-To: <56ibbl$6vn@kannews.ca.newbridge.com>
Message-Id: <Pine.SUN.3.91.961117101154.12547a-100000@is>
Mime-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII


On 15 Nov 1996, Glen Miner wrote:

> What's the difference between __dpmi_int() and int86()? 
> 
> I have read the docs under the libc.a reference but I think I need a
> translation. 

Any attempt to understand how library functions *really* work requires 
that you look into the library sources, IMHO.

The most significant difference is that `int86' invokes the 
protected-mode INT instruction, which is caught by the DPMI server and 
reflected to real mode, while `__dpmi_int' calls the interrupt-reflection 
DPMI service directly.

I suggest you use `__dpmi_int' unless compatibility to other compilers is 
an issue, because `int86' has some subtle aspects which have to do with 
the 16/32 bit issue of the registers that you pass.