[RFC] MIPS division by zero and libgcj...

Thu Jun 10 20:32:00 GMT 2004

Andrew Haley wrote:
>David Daney writes:
> > Andrew Haley wrote:
> > 
> > MIPS div instructions never trap. However I think that GCC always emits 
> > things like this when it cannot determine that the divisor is non zero:
> > 
> > div 0,ドル17,ドル16ドル
> > bne 16,ドル0,1ドルf
> > nop
> > break 7
> > 1:
> > 
> > 
>> > >No, there's no reason not to do it. You'll have to write some hairy
> > >code to satisfy all the rules, though.
> > >
> > What are the rules? Are they more complicated then throw an 
> > ArithmeticException when the divisor is zero?
>>Yes. You also have to do
>> if (dividend == (jint) 0x80000000L && divisor == -1)
> return dividend;
>>and not throw an exception.
>That is evidently what you have to do on i386. MIPS gives the right 
answer without faulting (i.e. hitting the break 7).
David Daney.