From: Charles Sandmann <sandmann AT new-orleans DOT NeoSoft DOT com>
Subject: Re: Interrupts and GO32.EXE
To: eliz AT is DOT elta DOT co DOT il (Eli Zaretskii)
Date: Wed, 21 Dec 1994 07:42:24 -0600 (CST)
Cc: djgpp AT sun DOT soe DOT clarkson DOT edu

> > Under GO32, hooking protected mode interrupts will only call your routine if
> > the interrupt occured in protected mode.  If the interrupt occurs in real
> > mode (during any call to DOS, for example) it would not be seen.  Under 
> > real DPMI, all HW interrupts are reflected back to you in protected mode,
> > even if they occured in real mode.
> 
> Is this also true when go32 runs in DPMI mode (like under Win3.1 or QDPMI)?

Under DPMI mode, this is handled by DPMI so all HW interrupts are 
reflected to PM, even if they occur in real mode.  There are some gotchas,
of course, you cannot look at the stack to see where you were executing
when the HW interrupt happened (DPMI handles HW ints on a different stack)
so things like our profiling code do not work.  To be fixed for V2.