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Re: [patch] Add Ada tasking support for hppa-unknown-linux-gnu
- From: "John David Anglin" <dave at hiauly1 dot hia dot nrc dot ca>
- To: charlet at adacore dot com (Arnaud Charlet)
- Cc: gcc-patches at gcc dot gnu dot org, laurent at guerby dot net, bosch at adacore dot com, dewar at adacore dot com
- Date: Thu, 7 Apr 2005 13:19:18 -0400 (EDT)
- Subject: Re: [patch] Add Ada tasking support for hppa-unknown-linux-gnu
> > * system-hpux.ads: Define Signed_Zeros to be True.
>
> I'll let Geert and/or Robert comment on this part, but I believe that it
> would not be correct to make this change.
Do you know why? The PA floating point co-processor is fully compatible
with ANSI/IEEE 754-1985. See page 8-7 of the PA-RISC 2.0 Architecture
book for the zero representation. The hardware supports signed zeros.
Earlier versions of the PA architecture didn't support fneg in
hardware. There was a problem with the implementation of neg[sd]f2
on the PA. These patterns didn't handle signed zeros correctly.
However, this problem has been fixed for some time.
As I said, this change on hppa-unknown-linux-gnu fixed the failured
of the signed zero test in cxg1005. The test machine had a PA 2.0
processor.
Dave
--
J. David Anglin dave.anglin@nrc-cnrc.gc.ca
National Research Council of Canada (613) 990-0752 (FAX: 952-6602)