asinh implmentation for 128-bit long doubles.

sysdeps/ieee754/ldbl-128/s_asinhl.c

@@ -0,0 +1,87 @@
+/* s_asinhl.c -- long double version of s_asinh.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
+
+/* asinhl(x)
+ * Method :
+ *      Based on
+ *              asinhl(x) = signl(x) * logl [ |x| + sqrtl(x*x+1) ]
+ *      we have
+ *      asinhl(x) := x  if  1+x*x=1,
+ *                := signl(x)*(logl(x)+ln2)) for large |x|, else
+ *                := signl(x)*logl(2|x|+1/(|x|+sqrtl(x*x+1))) if|x|>2, else
+ *                := signl(x)*log1pl(|x| + x^2/(1 + sqrtl(1+x^2)))
+ */
+
+#include "math.h"
+#include "math_private.h"
+
+#ifdef __STDC__
+static const long double
+#else
+static long double
+#endif
+  one = 1.0L,
+  ln2 = 6.931471805599453094172321214581765681e-1L,
+  huge = 1.0e+4900L;
+
+#ifdef __STDC__
+long double
+__asinhl (long double x)
+#else
+long double
+__asinhl (x)
+     long double x;
+#endif
+{
+  long double t, w;
+  int32_t ix, sign;
+  ieee854_long_double_shape_type u;
+
+  u.value = x;
+  sign = u.parts32.w0;
+  ix = sign & 0x7fffffff;
+  if (ix == 0x7fff0000)
+    return x + x;		/* x is inf or NaN */
+  if (ix < 0x3fc70000)
+    {				/* |x| < 2^ -56 */
+      if (huge + x > one)
+	return x;		/* return x inexact except 0 */
+    }
+  u.parts32.w0 = ix;
+  if (ix > 0x40350000)
+    {				/* |x| > 2 ^ 54 */
+      w = __ieee754_logl (u.value) + ln2;
+    }
+  else if (ix >0x40000000)
+    {				/* 2^ 54 > |x| > 2.0 */
+      t = u.value;
+      w = __ieee754_logl (2.0 * t + one / (__ieee754_sqrtl (x * x + one) + t));
+    }
+  else
+    {				/* 2.0 > |x| > 2 ^ -56 */
+      t = x * x;
+      w = __log1pl (u.value + t / (one + __ieee754_sqrtl (one + t)));
+    }
+  if (sign & 0x80000000)
+    return -w;
+  else
+    return w;
+}
+weak_alias (__asinhl, asinhl)