---
- branch: MAIN
  date: Thu Aug  1 02:06:31 UTC 2019
  files:
  - new: '1.11'
    old: '1.10'
    path: src/lib/libc/gdtoa/Makefile.inc
    pathrev: src/lib/libc/gdtoa/Makefile.inc@1.11
    type: modified
  - new: '1.2'
    old: 1.1.1.1
    path: src/lib/libc/gdtoa/gdtoa_fltrnds.h
    pathrev: src/lib/libc/gdtoa/gdtoa_fltrnds.h@1.2
    type: modified
  - new: '1.15'
    old: '1.14'
    path: src/lib/libc/gdtoa/gdtoaimp.h
    pathrev: src/lib/libc/gdtoa/gdtoaimp.h@1.15
    type: modified
  id: 20190801T020631Z.c7795f090ecf89c6eaa71c2b821dcaab8919b522
  log: |
    Honour the floating-point rounding mode in floating-point formatting.

    C99, Sec. 7.19.6.1 `The fprintf function', paragraph 13, p. 281:

       (Recommended practice)

       For e, E, f, F, g, and G conversions, if the number of significant
       decimal digits is at most DECIMAL_DIG, then the result should be
       correctly rounded.  If the number of significant decimal digits is
       more than DECIMAL_DIG but the source value is exactly
       representable with DECIMAL_DIG digits, then the result should be
       an exact representation with trailing zeros.  Otherwise, the
       source value is bounded by two adjacent decimal strings L < U,
       both having DECIMAL_DIG significant idgits; the value of the
       resultant decimal string D should satisfy L <= D <= U, _with the
       extra stipulation that the error should have a correct sign for
       the current rounding direction_.  [emphasis added]

    The gdtoa code base already supports respecting the floating-point
    rounding mode, as long as we compile it with Honor_FLT_ROUNDS
    defined.  However, for this to work, fegetround must be available in
    libc, which it is not currently -- the fenv logic is in libm.

    Fortunately, we don't have to move all of fenv from libm to libc --
    programs that do not link against libm don't have fesetround, so the
    rounding mode is always the default (barring asm shenanigans that
    bypass the API -- tough).  So use a weak reference to fegetround; by
    default, assume FE_TONEAREST if it is not defined.
  module: src
  subject: 'CVS commit: src/lib/libc/gdtoa'
  unixtime: '1564625191'
  user: riastradh