2005-02-11 Gregory W. Chicares <chicares at cox dot net>

Danny Smith  <dannysmith@users at sourceforge dot net>

	* include/math.h (expm1, expm1f, expmll): Add prototypes.
	* mingwex/Makefile.in (MATH_DISTFILES): Add expm1.c,
	expm1f.c, expm1l.c.
	(MATH_OBJS): Add expm1.o, expm1f.o, expm1l.o.
	* mingwex/math/expm1.c: New file.
	* mingwex/math/expm1f.c: New file.
	* mingwex/math/expm1l.c: New file.

winsup/mingw/mingwex/math/expm1f.c

@@ -0,0 +1,29 @@
+/*
+ * Written 2005 by Gregory W. Chicares <chicares@cox.net>.
+ * Adapted to float by Danny Smith <dannysmith@users.sourceforge.net>. 
+ * Public domain.
+ *
+ * F2XM1's input is constrained to (-1, +1), so the domain of
+ * 'x * LOG2EL' is (-LOGE2L, +LOGE2L). Outside that domain,
+ * delegating to exp() handles C99 7.12.6.3/2 range errors.
+ *
+ * Constants from moshier.net, file cephes/ldouble/constl.c,
+ * are used instead of M_LN2 and M_LOG2E, which would not be
+ * visible with 'gcc std=c99'. The use of these extended precision
+ * constants also allows gcc to replace them with x87 opcodes.
+ */
+
+#include <math.h> /* expl() */
+#include "cephes_mconf.h"
+
+float expm1f (float x)
+{
+  if (fabsf(x) < LOGE2L)
+    {
+      x *= LOG2EL;
+      __asm__("f2xm1" : "=t" (x) : "0" (x));
+      return x;
+    }
+  else
+    return expf(x) - 1.0F;
+}