interrupt far functions in Microsoft 5.1

[Andreas Kaiser]

In a message of <Jan 18 17:19>, Don Lorvig (lorvig at gsg.UUCP ) writes: 
 DL>  have been using void far interrupt routines for some time now.  The
 DL> addresses of this routines are passed to a TSR which executes them.
 DL> Recently I began attempting to make this functions more complex. (They
 DL> merely set flags before). When I attempt function calls from within
 DL> these interrupt routines, strange behavior results. 

I don't know if this is applicable to your problem, but the following is a 
common problem with interrupt routines in C (and perhaps the reason for the more 
sophisticated interrupt library in Zortech C):

Interrupt functions are called from everywhere, so you cannot assume the stack 
segment is the same as the data segment, which is a requirement at least for the 
small data models (small, medium). Thus an address within the interrupt 
function's stack frame (of a local variable) cannot be addressed via a near 
pointer, not even within the interrupt function itself. Should not be a problem 
in MSC's large model unless pointers are explicitly qualified as "near", but you 
didn't tell the model used.

                Andreas