Floating-point review

Sean Bruno sbruno at ignoranthack.me
Thu Oct 9 15:18:19 UTC 2014


On Wed, 2014-10-08 at 13:14 +0100, Andrew Turner wrote:
> I'm looking for someone who known more about floating-point than I do
> to review one of me changes. The change in question adds 6 new
> functions to the ARM libc to perform floating-point comparisons. These
> functions are required as part of the ABI spec.
> 
> The review is at [1]. I am mostly interested in having someone check
> __aeabi_cfcmpeq_helper and __aeabi_cdcmpeq_helper are correct. They
> should both return when either argument is a quiet NaN unless one is a
> signalling NaN for floats and doubles respectively.
> 
> These functions are used by a functions that is defined to not raise a
> floating point exception with comparing with quiet NaNs and all
> comparisons with signalling NaNs could potentially raise an exception.
> Because of this requirement these functions are used to filter out the
> cases we have one or more quiet NaNs and no signalling NaNs.
> 
> Andrew
> 
> [1] https://reviews.freebsd.org/D872

Andrew knows this, but I'll drop it here for the rest of you folks.

I've applied this patch and am seeing very good *compile* results from
my ports build science.  I might actually break 20k ports built this
run.

Please get folks who know compilers and C to look at this.  From my very
primitive eye it *seems* correct.

http://chips.ysv.freebsd.org/build.html?mastername=11armv6-default&build=2014-10-05_21h42m23s

sean



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