Optimize exp

Add __exp*_finite optimizations and rewrite some wrappers.

1 files changed, 35 insertions, 44 deletions

diff --git a/sysdeps/ieee754/dbl-64/w_exp.c b/sysdeps/ieee754/dbl-64/w_exp.c
index 1216492090..f1becff94c 100644
--- a/sysdeps/ieee754/dbl-64/w_exp.c
+++ b/sysdeps/ieee754/dbl-64/w_exp.c
@@ -1,55 +1,46 @@
-/* @(#)w_exp.c 5.1 93/09/24 */
-/*
- * ====================================================
- * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
- *
- * Developed at SunPro, a Sun Microsystems, Inc. business.
- * Permission to use, copy, modify, and distribute this
- * software is freely granted, provided that this notice
- * is preserved.
- * ====================================================
- */
-
-#if defined(LIBM_SCCS) && !defined(lint)
-static char rcsid[] = "$NetBSD: w_exp.c,v 1.6 1995/05/10 20:48:51 jtc Exp $";
-#endif
+/* Copyright (C) 2011 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Ulrich Drepper <drepper@gmail.com>, 2011.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
 
-/*
- * wrapper exp(x)
- */
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
 
-#include "math.h"
-#include "math_private.h"
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#include <math.h>
+#include <math_private.h>
 
-#ifdef __STDC__
 static const double
-#else
-static double
-#endif
 o_threshold=  7.09782712893383973096e+02,  /* 0x40862E42, 0xFEFA39EF */
 u_threshold= -7.45133219101941108420e+02;  /* 0xc0874910, 0xD52D3051 */
 
-#ifdef __STDC__
-	double __exp(double x)		/* wrapper exp */
-#else
-	double __exp(x)			/* wrapper exp */
-	double x;
-#endif
+
+/* wrapper exp */
+double
+__exp (double x)
 {
-#ifdef _IEEE_LIBM
-	return __ieee754_exp(x);
-#else
-	double z;
-	z = __ieee754_exp(x);
-	if(_LIB_VERSION == _IEEE_) return z;
-	if(__finite(x)) {
-	    if(x>o_threshold)
-	        return __kernel_standard(x,x,6); /* exp overflow */
-	    else if(x<u_threshold)
-	        return __kernel_standard(x,x,7); /* exp underflow */
-	}
-	return z;
-#endif
+  if (__builtin_expect (x > o_threshold, 0))
+    {
+      if (_LIB_VERSION != _IEEE_)
+	return __kernel_standard_f (x, x, 6);
+    }
+  else if (__builtin_expect (x < u_threshold, 0))
+    {
+      if (_LIB_VERSION != _IEEE_)
+	return __kernel_standard_f (x, x, 7);
+    }
+
+  return __ieee754_exp (x);
 }
 hidden_def (__exp)
 weak_alias (__exp, exp)