X-Recipient: archive-cygwin AT delorie DOT com
X-SWARE-Spam-Status: No, hits=-1.8 required=5.0 	tests=BAYES_00,RCVD_IN_DNSWL_NONE,TW_BN
X-Spam-Check-By: sourceware.org
Message-ID: <4BCF501A.7010809@x-ray.at>
Date: Wed, 21 Apr 2010 21:20:58 +0200
From: Reini Urban <rurban AT x-ray DOT at>
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; de; rv:1.9.1.9) Gecko/20100317 SeaMonkey/2.0.4
MIME-Version: 1.0
To: cygwin AT cygwin DOT com
Subject: Re: Cygwin Perl and -Duselongdouble
References: <B762313E2F744EE8A72B2113F081D0D3 AT desktop2>     <20070726121907 DOT GG19692 AT calimero DOT vinschen DOT de> <54421 DOT 64 DOT 81 DOT 167 DOT 122 DOT 1185478396 DOT squirrel AT webmail DOT efn DOT org>
In-Reply-To: <54421.64.81.167.122.1185478396.squirrel@webmail.efn.org>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit
X-IsSubscribed: yes
Mailing-List: contact cygwin-help AT cygwin DOT com; run by ezmlm
List-Id: <cygwin.cygwin.com>
List-Subscribe: <mailto:cygwin-subscribe AT cygwin DOT com>
List-Archive: <http://sourceware.org/ml/cygwin/>
List-Post: <mailto:cygwin AT cygwin DOT com>
List-Help: <mailto:cygwin-help AT cygwin DOT com>, <http://sourceware.org/ml/#faqs>
Sender: cygwin-owner AT cygwin DOT com
Mail-Followup-To: cygwin AT cygwin DOT com
Delivered-To: mailing list cygwin AT cygwin DOT com

Yitzchak Scott-Thoennes schrieb:
> On Thu, July 26, 2007 5:19 am, Corinna Vinschen wrote:
>> On Jul 26 22:09, Sisyphus wrote:
>>> I'd like to have a perl on Cygwin built with -Duselongdouble, so I tried
>
>>> *** You requested the use of long doubles but you do not seem to have
>>> *** the following mathematical functions needed for long double support:
>>>   ***     sqrtl modfl frexpl
>>
>> Long double functions are not supported by newlib so far.  There are a
>> couple of C99 functions not available in newlib.  Volunteers implementing
>> these functions in a license compatible way (BSD, not GPL) in newlib are
>> always welcome.
>
> Note that changing perl to use long doubles is a binary incompatible change.
> So if anyone is going to jump on this, it would be nice to have it happen
> before the already incompatible 5.10 is out Septemberish.
>
> modfl isn't strictly necessary; perl will substitute aintl (a solaris
> flavor of truncl) + copysignl.
> And ilogbl + scalbnl can be used to emulate frexpl.

I think I'll bite the bullet for the upcoming perl-5.12.0, for which I 
already have an API change (-Uusemymalloc) so adding -Duselongdouble can 
be easily added.

I dissected long doubles for my parrot pbc_compat work last year so I 
believe I can do modfl and frexpl without looking at GPL infected code.
http://code.google.com/p/cygwin-rurban/source/browse/trunk/release/parrot/patches/r36819-tt308-more-pf_items.patch

sqrtl is trivial in intel assembler:

long double sqrtl(long double ld) {
   long double _result;
   asm ("fsqrt" : "=t" (_result) : "0"(ld));
   return _result;
}

These questions are for newlib later:
Can I keep such a newlib code to 12-byte intel long doubles or must I 
add 16-byte long double support also?
Our gcc has -m128bit-long-double and the bastard -m96bit-long-double.
Does newlib needs papers?

I see a comment about --enable-newlib-hw-fp in
/usr/include/machine/ieeefp.h
I have no idea what this should be. Is there some hidden prior art?

I only know about Dave Korn's libm/machine/i386/f_*l.c stuff and I have 
newlib cvs.
-- 
Reini Urban
http://phpwiki.org/  http://murbreak.at/

--
Problem reports:       http://cygwin.com/problems.html
FAQ:                   http://cygwin.com/faq/
Documentation:         http://cygwin.com/docs.html
Unsubscribe info:      http://cygwin.com/ml/#unsubscribe-simple