1 files changed, 86 insertions, 0 deletions
diff --git a/sysdeps/ieee754/dbl-64/slowexp.c b/sysdeps/ieee754/dbl-64/slowexp.c
new file mode 100644
index 0000000..e8fa2e2
--- /dev/null
+++ b/sysdeps/ieee754/dbl-64/slowexp.c
@@ -0,0 +1,86 @@
+/*
+ * IBM Accurate Mathematical Library
+ * written by International Business Machines Corp.
+ * Copyright (C) 2001-2017 Free Software Foundation, Inc.
+ *
+ * This program 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.
+ *
+ * This program 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 this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+/**************************************************************************/
+/*  MODULE_NAME:slowexp.c                                                 */
+/*                                                                        */
+/*  FUNCTION:slowexp                                                      */
+/*                                                                        */
+/*  FILES NEEDED:mpa.h                                                    */
+/*               mpa.c mpexp.c                                            */
+/*                                                                        */
+/*Converting from double precision to Multi-precision and calculating     */
+/* e^x                                                                    */
+/**************************************************************************/
+#include <math_private.h>
+
+#include <stap-probe.h>
+
+#ifndef USE_LONG_DOUBLE_FOR_MP
+# include "mpa.h"
+void __mpexp (mp_no *x, mp_no *y, int p);
+#endif
+
+#ifndef SECTION
+# define SECTION
+#endif
+
+/*Converting from double precision to Multi-precision and calculating  e^x */
+double
+SECTION
+__slowexp (double x)
+{
+#ifndef USE_LONG_DOUBLE_FOR_MP
+  double w, z, res, eps = 3.0e-26;
+  int p;
+  mp_no mpx, mpy, mpz, mpw, mpeps, mpcor;
+
+  /* Use the multiple precision __MPEXP function to compute the exponential
+     First at 144 bits and if it is not accurate enough, at 768 bits.  */
+  p = 6;
+  __dbl_mp (x, &mpx, p);
+  __mpexp (&mpx, &mpy, p);
+  __dbl_mp (eps, &mpeps, p);
+  __mul (&mpeps, &mpy, &mpcor, p);
+  __add (&mpy, &mpcor, &mpw, p);
+  __sub (&mpy, &mpcor, &mpz, p);
+  __mp_dbl (&mpw, &w, p);
+  __mp_dbl (&mpz, &z, p);
+  if (w == z)
+    {
+      /* Track how often we get to the slow exp code plus
+	 its input/output values.  */
+      LIBC_PROBE (slowexp_p6, 2, &x, &w);
+      return w;
+    }
+  else
+    {
+      p = 32;
+      __dbl_mp (x, &mpx, p);
+      __mpexp (&mpx, &mpy, p);
+      __mp_dbl (&mpy, &res, p);
+
+      /* Track how often we get to the uber-slow exp code plus
+	 its input/output values.  */
+      LIBC_PROBE (slowexp_p32, 2, &x, &res);
+      return res;
+    }
+#else
+  return (double) __ieee754_expl((long double)x);
+#endif
+}