what are __ieee754_exp2l/__ieee754_log2l for?

[David Mosberger]

>>>>> On Thu, 11 Nov 2004 01:14:12 +0100, Andreas Schwab <schwab@suse.de> said:

  Andreas> They are the core of the C99 exp2l and log2l functions,
  Andreas> resp.  Nobody has yet written generic implementations of
  Andreas> them for 80-bit extended float.

Ah, looks like sysdeps/ia64/fpu is in need of a refresh.  v2.1 of the
Intel libm for Itanium does have exp2l (and log2l was introduced in
verison 1.4).

Can somebody clue me in on the meaning of the various math-library
file-name prefixes?  "w_" stands for "wrapper", I figured that one.
But what's the idea behind the "s_" vs. "e_" prefixes?

	--david