From:	"A.Appleyard" <A DOT APPLEYARD AT fs2 DOT mt DOT umist DOT ac DOT uk>
To:	eliz AT is DOT elta DOT co DOT il, DJGPP AT SUN DOT SOE DOT CLARKSON DOT EDU
Date:	Fri, 28 Apr 1995 09:19:14 BST
Subject:	Gnu C++ odd event on divide by zero: the mice got at it!!!

  I complained about odd behaviour on divide by zero in this test program:-
#include<stdio.h>
main(){double x,y; x=0; y=1/x;}

  Stephen Turnbull <turnbull AT shako DOT sk DOT tsukuba DOT ac DOT jp> replied:-

> ... Mr. Appleyard was one of the guys who has objections to the default
> behavior of the coprocessor flags in DJGPP (in particular with respect to
> exception trapping). If so, and he figured out how to get the flags reset
> with any of the several solutions that were posted, and he has run any of
> his programs that muck with the default behavior of the '87....

  (1) About when were these `several solutions' posted? Any chance of someone
emailing them to me personally? I am sorry to trouble you.
  (2) This morning (by REM'ing out lines in my C:\AUTOEXEC.BAT) I found that
if I stop using the mouse handler that came with my Anubis mouse, and instead
use an ordinary Microsoft mouse handler (MOUSE.COM, 26677 bytes, created at
12.34.38 on 18 Jan 1990) that was hanging about in my filestore, the trouble
goes away and the above test program causes a full proper hex dump as follows.
  (3) This is the second fault I have found in the Anubis mouse handler. I can
set it up in 2-button or 3-button mode. If I set it up in 3-button mode, Word
Perfect and Windows don't see the mouse. So I set it up in 2-button mode, and
I have the above divide-by-zero nuisance AND no middle mouse button. Please
does anyone know a mouse handler that works with 2-button AND 3-button mice
and does not have the abovementioned faults?
 ====================
Floating Point exception at eip=1c2
eax=00000000 ebx=7ffffe24 ecx=00000000 edx=00003004 esi=00000000 edi=00000000
ebp=7ffffe10 esp=7ffffe00 cs=d8 ds=48 es=48 fs=48 gs=38 ss=48 cr2=00003000
Call frame traceback EIPs:
  0x000001c2

Contents of stack:
  stack[0x7ffffe00] = 0x00000000	  stack[0x7ffffe02] = 0xfe100000
  stack[0x7ffffe04] = 0x7ffffe10	  stack[0x7ffffe06] = 0x00007fff
  stack[0x7ffffe08] = 0x00000000	  stack[0x7ffffe0a] = 0x00000000
   <etc etc etc>

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