This is the mail archive of the
mailing list for the GCC project.
Re: ia64 XFmode patch rides again (need ia64-linux testing)
> Jan Hubicka <email@example.com> writes:
> >> I am confused. I thought __float128 and "long double" were both going
> >> to be 80-bit IEEE extended in an 128-bit field on x86-64. What you
> >> are saying now makes it sound like __float128 is a different type
> >> altogether (IEEE quad?). If this is so, you'll need to mention TFmode
> > __float128 is supposed to be IEEE quad. long double is supposed to be
> > 80-bit IEEE in 128-bit.
> Ah, okay, then you will need both XFmode and TFmode in i386-modes.def.
> You can probably copy much of ia64-modes.def; just get rid of the HPUX
> specific gunk.
Well, that is precisely what I did.
> >> Do you have the most recent version of genmodes.c?
> > So the sollution really is easy :) I didn't updated since yesterday.
> Odd, that code went in on Friday with the ia64 backend changes. Check
> for sticky tags.
Actually I was traveling for few days so it is quite posible that my
tree was older. I however had the ia-64 changes in. Weird..
I guess my tree got just partly updated for some reason, so no surprise
that things got messed up in my tests. Sorry for the confusion.
> > So the right sollution would be to provide both *xf *tf with the same
> > semnatics + TFmode libcalls under new names...
> Yes, I think so. And, as Richard points out, the *xf symbols should
> be versioned GCC_3.4; come to think of it, the same is true on ia64,
> but I don't know how to do that.
Well, me neither. For now I will copy what you do have in IA-64 so we
are in sync. There is not much need to make these different and lets
work this out afterwards.
> >> You'll have to rename all the TFmode libcalls to some other
> >> convention. For IA64, it seems sensible to make the HP-UX
> >> convention be used everywhere. Does AMD maybe have a document
> >> defining software float library routines?
> > No, but we can write one. Any particular prefferences in
> > convention? Or taking the HP-UX names you do use would be OK?
> I have no preference at present. You can look in
> ia64.c:ia64_hpux_init_libfuncs (IIRC) for the HP-UX names. Note that
I copied these already...
> GCC's floating point emulation library does not support IEEE quad, so
> the question is moot until that gets resolved. (Or does x86-64
> support this in hardware?)
No, it doesn't. I tought that there is at least one implementation in
glibc used by SPARC sofware emulation available but I never really
checked it out. Not sure whether it is C or assembly or whether it
exists at all..