2.5-18.1

1 files changed, 98 insertions, 0 deletions

diff --git a/sysdeps/ieee754/ldbl-128ibm/s_roundl.c b/sysdeps/ieee754/ldbl-128ibm/s_roundl.c
new file mode 100644
index 0000000000..0880e6ee22
--- /dev/null
+++ b/sysdeps/ieee754/ldbl-128ibm/s_roundl.c
@@ -0,0 +1,98 @@
+/* Round to int long double floating-point values.
+   IBM extended format long double version.
+   Copyright (C) 2006 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, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+/* This has been coded in assembler because GCC makes such a mess of it
+   when it's coded in C.  */
+
+#include <math.h>
+#include <fenv_libc.h>
+#include <math_ldbl_opt.h>
+#include <float.h>
+#include <ieee754.h>
+
+
+#ifdef __STDC__
+long double
+__roundl (long double x)
+#else
+long double
+__roundl (x)
+     long double x;
+#endif
+{
+  double xh, xl, hi, lo;
+
+  ldbl_unpack (x, &xh, &xl);
+
+  /* Return Inf, Nan, +/-0 unchanged.  */
+  if (__builtin_expect (xh != 0.0
+			&& __builtin_isless (__builtin_fabs (xh),
+					     __builtin_inf ()), 1))
+    {
+      double orig_xh;
+      int save_round = fegetround ();
+
+      /* Long double arithmetic, including the canonicalisation below,
+	 only works in round-to-nearest mode.  */
+      fesetround (FE_TONEAREST);
+
+      /* Convert the high double to integer.  */
+      orig_xh = xh;
+      hi = ldbl_nearbyint (xh);
+
+      /* Subtract integral high part from the value.  */
+      xh -= hi;
+      ldbl_canonicalize (&xh, &xl);
+
+      /* Now convert the low double, adjusted for any remainder from the
+	 high double.  */
+      lo = ldbl_nearbyint (xh);
+
+      /* Adjust the result when the remainder is exactly 0.5.  nearbyint
+	 rounds values halfway between integers to the nearest even
+	 integer.  roundl must round away from zero.
+	 Also correct cases where nearbyint returns an incorrect value
+	 for LO.  */
+      xh -= lo;
+      ldbl_canonicalize (&xh, &xl);
+      if (xh == 0.5)
+	{
+	  if (xl > 0.0 || (xl == 0.0 && orig_xh > 0.0))
+	    lo += 1.0;
+	}
+      else if (-xh == 0.5)
+	{
+	  if (xl < 0.0 || (xl == 0.0 && orig_xh < 0.0))
+	    lo -= 1.0;
+	}
+
+      /* Ensure the final value is canonical.  In certain cases,
+	 rounding causes hi,lo calculated so far to be non-canonical.  */
+      xh = hi;
+      xl = lo;
+      ldbl_canonicalize (&xh, &xl);
+
+      fesetround (save_round);
+    }
+
+  return ldbl_pack (xh, xl);
+}
+
+long_double_symbol (libm, __roundl, roundl);