import newlib-2000-02-17 snapshot

1 files changed, 114 insertions, 0 deletions

diff --git a/newlib/libm/math/s_frexp.c b/newlib/libm/math/s_frexp.c
new file mode 100644
index 000000000..aaa36068a
--- /dev/null
+++ b/newlib/libm/math/s_frexp.c
@@ -0,0 +1,114 @@
+
+/* @(#)s_frexp.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
+       <<frexp>>, <<frexpf>>---split floating-point number
+INDEX
+	frexp
+INDEX
+	frexpf
+
+ANSI_SYNOPSIS
+	#include <math.h>
+        double frexp(double <[val]>, int *<[exp]>);
+        float frexpf(float <[val]>, int *<[exp]>);
+
+TRAD_SYNOPSIS
+	#include <math.h>
+        double frexp(<[val]>, <[exp]>)
+        double <[val]>;
+        int *<[exp]>;
+
+        float frexpf(<[val]>, <[exp]>)
+        float <[val]>;
+        int *<[exp]>;
+
+
+DESCRIPTION
+	All non zero, normal numbers can be described as <[m]> * 2**<[p]>.
+	<<frexp>> represents the double <[val]> as a mantissa <[m]>
+	and a power of two <[p]>. The resulting mantissa will always
+	be greater than or equal to <<0.5>>, and less than <<1.0>> (as
+	long as <[val]> is nonzero). The power of two will be stored
+	in <<*>><[exp]>. 
+
+@ifinfo
+<[m]> and <[p]> are calculated so that
+<[val]> is <[m]> times <<2>> to the power <[p]>.
+@end ifinfo
+@tex
+<[m]> and <[p]> are calculated so that
+$ val = m \times 2^p $.
+@end tex
+
+<<frexpf>> is identical, other than taking and returning
+floats rather than doubles.
+
+RETURNS
+<<frexp>> returns the mantissa <[m]>. If <[val]> is <<0>>, infinity,
+or Nan, <<frexp>> will set <<*>><[exp]> to <<0>> and return <[val]>.
+
+PORTABILITY
+<<frexp>> is ANSI.
+<<frexpf>> is an extension.
+
+
+*/
+
+/*
+ * for non-zero x 
+ *	x = frexp(arg,&exp);
+ * return a double fp quantity x such that 0.5 <= |x| <1.0
+ * and the corresponding binary exponent "exp". That is
+ *	arg = x*2^exp.
+ * If arg is inf, 0.0, or NaN, then frexp(arg,&exp) returns arg 
+ * with *exp=0. 
+ */
+
+#include "fdlibm.h"
+
+#ifndef _DOUBLE_IS_32BITS
+
+#ifdef __STDC__
+static const double
+#else
+static double
+#endif
+two54 =  1.80143985094819840000e+16; /* 0x43500000, 0x00000000 */
+
+#ifdef __STDC__
+	double frexp(double x, int *eptr)
+#else
+	double frexp(x, eptr)
+	double x; int *eptr;
+#endif
+{
+	__int32_t hx, ix, lx;
+	EXTRACT_WORDS(hx,lx,x);
+	ix = 0x7fffffff&hx;
+	*eptr = 0;
+	if(ix>=0x7ff00000||((ix|lx)==0)) return x;	/* 0,inf,nan */
+	if (ix<0x00100000) {		/* subnormal */
+	    x *= two54;
+	    GET_HIGH_WORD(hx,x);
+	    ix = hx&0x7fffffff;
+	    *eptr = -54;
+	}
+	*eptr += (ix>>20)-1022;
+	hx = (hx&0x800fffff)|0x3fe00000;
+	SET_HIGH_WORD(x,hx);
+	return x;
+}
+
+#endif /* _DOUBLE_IS_32BITS */