Date: Tue, 1 Nov 94 00:28 GMT
From: shaw AT cix DOT compulink DOT co DOT uk (Shaw Carruthers)
Subject: Re: GCC 260 Maths Bug 
To: eliz AT is DOT elta DOT co DOT il
Cc: shaw AT cix DOT compulink DOT co DOT uk, djgpp AT sun DOT soe DOT clarkson DOT edu
Reply-To: shaw AT cix DOT compulink DOT co DOT uk

In-Reply-To: <9410301153 DOT AA20683 AT is DOT elta DOT co DOT il>
> From: "Eli Zaretskii" <eliz AT is DOT elta DOT co DOT il>
> 
> I also have 486DX266 with DOS 6.2, but your program works for me.
> It indeed returns 0x80000000, unless compiled with -O, in which
> case the compiler correctly prints a warning about overflow
> (under -Wall switch) and the program returns 0x7fffffff.

Many thanks for your helpful comments.

With the -O option the error is handled at compile time and code 
generated to printf 0x7fffffff.

It has been suggested to me that my problem is hardware related in that 
the 486 is set to operate in AT compatibility mode where fperrors are 
converted to IRQ 13 and that my motherboard is not wired correctly for 
this. I am investigating this further. 

Code to do the same assignment in Fortran and Assembler both yield 
0x80000000 on my PC, so there must be some code based difference at the 
bottom of it all, perhaps the way the 486 control flags are set by GCC?