Powerpc64 long double support

[Richard Sandiford]

Alan Modra <amodra@bigpond.net.au> writes:
> On Wed, Mar 10, 2004 at 09:31:13PM +1030, Alan Modra wrote:
>> On Wed, Mar 10, 2004 at 09:42:36AM +0000, Richard Sandiford wrote:
>> > when compiled with MIPSpro cc.
>> 
>> Does MIPSpro correctly convert a long double -0.0 to double -0.0?  Does
>> mips gcc?
>
> The reason for -0.0 in the low double goes like this:
>
> Conversion from long double to double is done by simply adding the
> two component doubles.  That means long double -0.0 must be
> (-0.0 + -0.0), or you need to add code to handle -0.0 on every
> conversion.

Not sure: are you saying that's what the spec says you should do, or
that is it just what a particular implementation does?  As per my
previous message, IRIX uses +0.0 for the low double and it still gets
the conversion right.  I assume it must be using something other than
simple addition.

My only concern (in case it wasn't obvious ;) is that you don't
change the behaviour for IRIX.  I'm certainly not trying to say
the change is wrong for powerpc...

Richard