Date: Sat, 4 Feb 2006 04:58:40 +1100 (EST) From: Bruce Evans <bde@zeta.org.au> To: "O. Hartmann" <ohartman@uni-mainz.de> Cc: "O. Hartmann" <ohartman@mail.uni-mainz.de>, freebsd-stable@FreeBSD.org, freebsd-amd64@FreeBSD.org Subject: Re: missing fpresetsticky in ieeefp.h Message-ID: <20060204042336.F11473@delplex.bde.org> In-Reply-To: <43E1FD40.9060408@uni-mainz.de> References: <43E1D1E9.3000302@mail.uni-mainz.de> <43E1E8B0.3030702@uni-mainz.de> <20060202224815.K7234@delplex.bde.org> <43E1FD40.9060408@uni-mainz.de>
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On Thu, 2 Feb 2006, O. Hartmann wrote:
> Bruce Evans schrieb:
>> On Thu, 2 Feb 2006, O. Hartmann wrote:
>> ...
>>>> Now take a look into <machine/ieeefp.h>, where this function should be
>>>> declared. Nothing, I can not find this routine, it seems to be 'not
>>>> available' on my FreeBSD6.1-PRERELEASE AMD64 (no 32Bit compatibility).
>>
>> It was removed for amd64 and never existed for some other arches. It was
[fresetsticky()]
>> apparently unused when it was removed a year ago.
>> ...
>> % RCS file: /home/ncvs/src/sys/amd64/include/ieeefp.h,v
>> ...
>> % revision 1.13
> ...
> Thanks a lot. In prior software compilations of GMT on FBSD/AMD64 I commented
> out the appropriate line in gmt_init.c without any hazardous effects - but I
> never used GMT that intensive having ever recognozed any malicious side
> effects.
>
> I should contact the guys from Soest/Hawaii asking them for any serious
> effects commenting out this line on amd64 architectures.
I think it is probably used only for error detection, if at all.
Accumulated IEEE exceptions are supposed to be read using fpgetsticky()
and then cleared using fp[re]setsticky() so that the next set accumulated
can be distinguished from the old set. Applications should now use
fesetexceptflag() instead of fp[re]setsticky().
BTW, the most useful fp* functions other than fp[re]setsticky(), namely
fp{get,set}round(), never worked on ia64 due to the rounding flags
values being misspelled, so there are unlikely to be any portable uses
of the fp* functions in ports. The corresponding fe{get,set}round()
functions work on at least i386, amd64 and ia64.
Bruce
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