[Mingw-users] expm1()

[Greg C. <chi...@co...>]

log1p() would be much more useful if its companion expm1()
[C99 7.12.6.3] were provided as well. Is there a reason not
to have expm1(), other than "no one has contributed it yet"?

For instance, Conklin, credited as the original author of
   /mingw/runtime/mingwex/math/log1pl.S?rev=1.1&view=markup
said in an earlier version
   http://www.klid.dk/pub/gnu/gnu-utils/src/libm/src/s_log1p.s

   /*
    * Since the fyl2xp1 instruction has such a limited range:
    *	-(1 - (sqrt(2) / 2)) <= x <= sqrt(2) - 1
    * it's not worth trying to use it.
    */

but apparently later realized its worth. Did something like
that happen for expm1()? Hmm...I find Conklin's log1p() in the
netbsd src/lib/libm sources, but no corresponding expm1().

I realize expm1() will be an intrinsic in gcc-4.0
   http://www.gnu.org/software/gcc/gcc-4.0/changes.html
but apparently only with '-ffast-math', so there's still
a use for an expm1() that conforms to the language and
numeric standards.