genericopenlibs/cstdlib/LMATH/S_LDEXP.C
changeset 31 ce057bb09d0b
parent 0 e4d67989cc36
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/genericopenlibs/cstdlib/LMATH/S_LDEXP.C	Fri Jun 04 16:20:51 2010 +0100
@@ -0,0 +1,86 @@
+/* S_LDEXP.C
+ * 
+ * Portions Copyright (c) 1993-2005 Nokia Corporation and/or its subsidiary(-ies).
+ * All rights reserved.
+ */
+
+
+/* @(#)s_ldexp.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.
+ * ====================================================
+ */
+
+/*
+FUNCTION
+       <<ldexp>>, <<ldexpf>>---load exponent
+
+INDEX
+	ldexp
+INDEX
+	ldexpf
+
+ANSI_SYNOPSIS
+       #include <math.h>
+       double ldexp(double <[val]>, int <[exp]>);
+       float ldexpf(float <[val]>, int <[exp]>);
+
+TRAD_SYNOPSIS
+       #include <math.h>
+
+       double ldexp(<[val]>, <[exp]>)
+              double <[val]>;
+              int <[exp]>;
+
+       float ldexpf(<[val]>, <[exp]>)
+              float <[val]>;
+              int <[exp]>;
+
+
+DESCRIPTION
+<<ldexp>> calculates the value 
+@ifinfo
+<[val]> times 2 to the power <[exp]>.
+@end ifinfo
+@tex
+$val\times 2^{exp}$.
+@end tex
+<<ldexpf>> is identical, save that it takes and returns <<float>>
+rather than <<double>> values.
+
+RETURNS
+<<ldexp>> returns the calculated value.
+
+Underflow and overflow both set <<errno>> to <<ERANGE>>.
+On underflow, <<ldexp>> and <<ldexpf>> return 0.0.
+On overflow, <<ldexp>> returns plus or minus <<HUGE_VAL>>.
+
+PORTABILITY
+<<ldexp>> is ANSI, <<ldexpf>> is an extension.
+              
+*/   
+
+#include "FDLIBM.H"
+#include <errno.h>
+
+/**
+Get floating-point value from mantissa and exponent.
+Calculates the floating point value corresponding to 
+the given mantissa and exponent
+@return   Floating-point value equal to value * 2exp.
+@param x Floating point value representing mantissa 
+@param exp Integer exponent
+*/	
+EXPORT_C double ldexp(double value, int exp) __SOFTFP
+{
+	if(!finite(value)||value==0.0) return value;
+	value = scalbn(value,exp);
+	if(!finite(value)||value==0.0) errno = ERANGE;
+	return value;
+}