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Re: FLOATING-POINT CONSISTENCY, -FFLOAT-STORE, AND X86
>>>>> "Marc" == Marc Lehmann <pcg@goof.com> writes:
>> What's the guarantee that crt0 sets up extended precision on
>> whichever systems are of interest?
Marc> I have no idea. Do _you_ have one?
No, or I wouldn't have asked. AFAIR the startup settings of the FPU
changed at some stage in the past, though.
>> Is it currently consistent across all the x86 platforms we run on?
Marc> Definitely not. But does that mean we should break linux-libm
Marc> (for example) because solaris behavuour wasn't consistent
Marc> before(?).
Of course not. I need libm to work; that's why I keep asking the
question. I presume that glibc would need to conform on another
platform that did define this.
Marc> How about implementing the __setfpucw functionality as found on
Marc> linux? Creating a library (-lrdble) should be trivial then.
I don't have the information, expertise or interest in that. I called
__setfpucw, but I'm not even sure it works across Linuxes. I'd do
newlib and cygwin32 as well, given appropriate doc and a way of
figuring out that they're in use; AFAIR they seem to have the facility
but don't say how to drive it. I'd expect people with an interest to
contribute the (presumably trivial) additions.