math: add exception handling functionality

According to standards SVID and SYSV.
Modified lgamma calling in case when 'signgam' variable should not be used.

Signed-off-by: Waldemar Brodkorb <wbx@uclibc-ng.org>

1 files changed, 95 insertions, 0 deletions

diff --git a/libm/w_jnl.c b/libm/w_jnl.c
new file mode 100644
index 000000000..773391d07
--- /dev/null
+++ b/libm/w_jnl.c
@@ -0,0 +1,95 @@
+/* w_jnl.c -- long double version of w_jn.c.
+ * Conversion to long double by Ulrich Drepper,
+ * Cygnus Support, drepper@cygnus.com.
+ */
+
+/*
+ * ====================================================
+ * 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: $";
+#endif
+
+/*
+ * wrapper jn(int n, double x), yn(int n, double x)
+ * floating point Bessel's function of the 1st and 2nd kind
+ * of order n
+ *
+ * Special cases:
+ *	y0(0)=y1(0)=yn(n,0) = -inf with division by zero signal;
+ *	y0(-ve)=y1(-ve)=yn(n,-ve) are NaN with invalid signal.
+ * Note 2. About jn(n,x), yn(n,x)
+ *	For n=0, j0(x) is called,
+ *	for n=1, j1(x) is called,
+ *	for n<x, forward recursion us used starting
+ *	from values of j0(x) and j1(x).
+ *	for n>x, a continued fraction approximation to
+ *	j(n,x)/j(n-1,x) is evaluated and then backward
+ *	recursion is used starting from a supposed value
+ *	for j(n,x). The resulting value of j(0,x) is
+ *	compared with the actual value to correct the
+ *	supposed value of j(n,x).
+ *
+ *	yn(n,x) is similar in all respects, except
+ *	that forward recursion is used for all
+ *	values of n>1.
+ *
+ */
+
+#include <math.h>
+#include "math_private.h"
+
+#if !defined __NO_LONG_DOUBLE_MATH
+# ifndef __DO_XSI_MATH__
+long double
+jnl(int n, long double x)	/* wrapper jnl */
+{
+#  if __UCLIBC_HAS_FENV__
+	long double z;
+	z = (long double) __ieee754_jn(n, (double) x);
+	if (_LIB_VERSION == _IEEE_
+	    || _LIB_VERSION == _POSIX_
+	    || isnan(x))
+	  return z;
+	if(fabsl(x)>X_TLOSS) {
+	    return __kernel_standard_l((double)n,x,238); /* jn(|x|>X_TLOSS,n) */
+	} else
+		return z;
+#  else
+	return (long double) __ieee754_jn(n, (double) x);
+#  endif /* __UCLIBC_HAS_FENV__ */
+}
+
+long double
+ynl(int n, long double x)	/* wrapper ynl */
+{
+#  if __UCLIBC_HAS_FENV__
+	long double z;
+	z = (long double) __ieee754_yn(n,(double) x);
+	if(_LIB_VERSION == _IEEE_ || isnan(x) ) return z;
+        if(x <= 0.0){
+                if(x==0.0)
+                    /* d= -one/(x-x); */
+                    return __kernel_standard_l((double)n,x,212);
+                else
+                    /* d = zero/(x-x); */
+                    return __kernel_standard_l((double)n,x,213);
+        }
+	if(x>X_TLOSS && _LIB_VERSION != _POSIX_) {
+	    return __kernel_standard_l((double)n,x,239); /* yn(x>X_TLOSS,n) */
+	} else
+		return z;
+#  else
+	return (long double) __ieee754_yn(n,(double) x);
+#  endif /* __UCLIBC_HAS_FENV__ */
+}
+# endif /* __DO_XSI_MATH__ */
+#endif /* __NO_LONG_DOUBLE_MATH */