import newlib-2000-02-17 snapshot

1 files changed, 45 insertions, 0 deletions

diff --git a/newlib/libc/machine/i386/f_expf.c b/newlib/libc/machine/i386/f_expf.c
new file mode 100644
index 000000000..438772764
--- /dev/null
+++ b/newlib/libc/machine/i386/f_expf.c
@@ -0,0 +1,45 @@
+/*
+ * ====================================================
+ * Copyright (C) 1998 by Cygnus Solutions. All rights reserved.
+ *
+ * Permission to use, copy, modify, and distribute this
+ * software is freely granted, provided that this notice
+ * is preserved.
+ * ====================================================
+ */
+
+/*
+Fast version of exp using Intel float instructions.
+
+   float _f_expf (float x);
+
+Function computes e ** x.  The following special cases exist:
+   1. if x is 0.0 ==> return 1.0
+   2. if x is infinity ==> return infinity
+   3. if x is -infinity ==> return 0.0
+   4. if x is NaN ==> return x
+There is no error checking or setting of errno.
+*/
+
+
+#include <math.h>
+#include <ieeefp.h>
+#include "f_math.h"
+
+float _f_expf (float x)
+{
+   if (check_finitef(x))
+     {
+       float result;
+       asm ("fldl2e; fmulp; fld %%st; frndint; fsub %%st,%%st(1); fxch;" \
+          "fchs; f2xm1; fld1; faddp; fxch; fld1; fscale; fstp %%st(1); fmulp" :
+          "=t"(result) : "0"(x));
+       return result;
+     }
+   else if (x == -infinityf())
+     return 0.0;
+
+   return x;
+}
+
+