Date: Mon, 23 May 94 10:33:22 EDT
From: peprbv AT cfa0 DOT harvard DOT edu (Bob Babcock)
To: CROBINSO AT VAXC DOT STEVENS-TECH DOT EDU
Cc: djgpp AT sun DOT soe DOT clarkson DOT edu
Subject: Re: Interrupts - Real/Protected modes?
Reply-To: babcock AT cfa DOT harvard DOT edu

> When I use _go32_dpmi_simulate_int() is the system still in protected mode
> when it calls the interrupt?

No, you switch to real mode to execute the interrupt so that you can issue
interrupts which are not supported by go32.

> I have no idea whether this has any effect or not, but I managed to get INT
> 21h vector 09h to work correctly (display a string pointed to by DS:DX) and
> used the same method to point to the data block for the interrupt, but when I
> set the same thing up under something like Borland (real mode) it works and
> under DJGPP it either hangs or returns incorrect info.

Remember that if you are executing the interrupt in real mode, the data must
be in the first MB of memory.  Have you allocated some DOS memory to use as a
data area and copied your string into it?