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, 107 insertions, 0 deletions

diff --git a/libm/k_standardl.c b/libm/k_standardl.c
new file mode 100644
index 000000000..19d2a3ec2
--- /dev/null
+++ b/libm/k_standardl.c
@@ -0,0 +1,107 @@
+/* Implement __kernel_standard_l.
+   Copyright (C) 2012-2016 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   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.
+
+   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.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.
+
+   Parts based on k_standard.c from fdlibm: */
+
+/* @(#)k_standard.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.
+ * ====================================================
+ */
+
+#include <math.h>
+#include "math_private.h"
+#include <fenv.h>
+#include <float.h>
+#include <errno.h>
+
+
+static double zero = 0.0;
+
+/* Handle errors for a libm function as specified by TYPE (see
+   comments in k_standard.c for details), with arguments X and Y,
+   returning the appropriate return value for that function.  */
+
+long double
+__kernel_standard_l (long double x, long double y, int type)
+{
+  double dx, dy;
+  struct exception exc;
+  fenv_t env;
+
+  feholdexcept (&env);
+  dx = x;
+  dy = y;
+  math_force_eval (dx);
+  math_force_eval (dy);
+  fesetenv (&env);
+
+  switch (type)
+    {
+    case 221:
+      /* powl (x, y) overflow.  */
+      exc.arg1 = dx;
+      exc.arg2 = dy;
+      exc.type = OVERFLOW;
+      exc.name = (char *) "powl";
+      if (_LIB_VERSION == _SVID_)
+	{
+	  exc.retval = HUGE;
+	  y *= 0.5;
+	  if (x < zero && rint (y) != y)
+	    exc.retval = -HUGE;
+	}
+      else
+	{
+	  exc.retval = HUGE_VAL;
+	  y *= 0.5;
+	  if (x < zero && rint (y) != y)
+	    exc.retval = -HUGE_VAL;
+	}
+      if (_LIB_VERSION == _POSIX_)
+	__set_errno (ERANGE);
+      else if (!matherr (&exc))
+	__set_errno (ERANGE);
+      return exc.retval;
+
+    case 222:
+      /* powl (x, y) underflow.  */
+      exc.arg1 = dx;
+      exc.arg2 = dy;
+      exc.type = UNDERFLOW;
+      exc.name = (char *) "powl";
+      exc.retval = zero;
+      y *= 0.5;
+      if (x < zero && rint (y) != y)
+	exc.retval = -zero;
+      if (_LIB_VERSION == _POSIX_)
+	__set_errno (ERANGE);
+      else if (!matherr (&exc))
+	__set_errno (ERANGE);
+      return exc.retval;
+
+    default:
+      return __kernel_standard (dx, dy, type);
+    }
+}