[Boost-bugs] [Boost C++ Libraries] #12524: cpp_bin_float: Anal fixation. Part 1. Sign of zero result of summation.

Subject: [Boost-bugs] [Boost C++ Libraries] #12524: cpp_bin_float: Anal fixation. Part 1. Sign of zero result of summation.
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2016-10-13 19:49:26

#12524: cpp_bin_float: Anal fixation. Part 1. Sign of zero result of summation.
------------------------------+----------------------------
 Reporter:  Michael Shatz     |      Owner:  johnmaddock
     Type:  Feature Requests  |     Status:  new
Milestone:  To Be Determined  |  Component:  multiprecision
  Version:  Boost 1.62.0      |   Severity:  Cosmetic
 Keywords:                    |
------------------------------+----------------------------
 IEEE-754 has one simple rule - subtraction of two equal finite numbers
 results in +0.
 From here follows that there are only two cases in which
 subtraction/addition of zeros results in -0:
  -0 + -0  and -0 - +0. All other combinations results in +0.

 Also from here follows that subtraction/addition of non-zeros with equal
 absolute value never results in -0.

 I see no good reasons why boost::cpp_bin_float should not follow the same
 conventions.
 But right now it does not.

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/12524>
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