HI:

This can happen if you are using an array and the index pointer points to an
location in stack that is less than absolute stack location of zero.

Example:
a, b and c are defined as 1 word each, and d is defined as one word with 5
elements.
d index 5 is the last element of d;
d index - 5 points to a location before stack definition.

Hope this helps.

Olav.

"TRAPP,RICH (Non-A-Loveland,ex1)" wrote:

> Jean,
>   This can happen when the program code tries to pop too many words off of
> the stack.  If you're doing anything with control-y traps, the trap handler
> may be trashing the stack and or jumping into the wrong place in the code
> and doing a pop when it shouldn't be.
>
> RAT
>
>
>
> Rich Trapp <mailto:[log in to unmask]>
>
>
> Consulting for Agilent Technologies, Loveland, Colorado.
>
> Managed Business Solutions <http://www.mbsnav.com/>
> 200 South College Avenue
> Fort Collins, Colorado 80524-2811
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> 970.669.3071 (fax)
>
> -----Original Message-----
> From: LES BUREAUX DE CRÉDIT DU NORD INC [mailto:[log in to unmask]]
> Sent: Thursday, March 22, 2001 1:04 PM
> To: [log in to unmask]
> Subject: What could cause a STACK UNDERFLOW in S.P.L.?????????
>
> I've heard of stack overflow, but not underflow.  I found very little
> information on the newsgroup library.  After removing several segments of
> SPL programs causing a BOUND VIOLATION, the computer is still not happy and
> responds with a STACK UNDERFLOW.
>
> Jean Huot
> Northern Credit Bureaus Inc.