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authorJakub Jelinek <jakub@redhat.com>2007-07-12 18:26:36 +0000
committerJakub Jelinek <jakub@redhat.com>2007-07-12 18:26:36 +0000
commit0ecb606cb6cf65de1d9fc8a919bceb4be476c602 (patch)
tree2ea1f8305970753e4a657acb2ccc15ca3eec8e2c /sysdeps/ieee754/ldbl-128ibm/s_lroundl.c
parent7d58530341304d403a6626d7f7a1913165fe2f32 (diff)
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2.5-18.1
Diffstat (limited to 'sysdeps/ieee754/ldbl-128ibm/s_lroundl.c')
-rw-r--r--sysdeps/ieee754/ldbl-128ibm/s_lroundl.c142
1 files changed, 142 insertions, 0 deletions
diff --git a/sysdeps/ieee754/ldbl-128ibm/s_lroundl.c b/sysdeps/ieee754/ldbl-128ibm/s_lroundl.c
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+++ b/sysdeps/ieee754/ldbl-128ibm/s_lroundl.c
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+/* Round to long 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.  */
+
+#include <math.h>
+#include <fenv_libc.h>
+#include <math_ldbl_opt.h>
+#include <float.h>
+#include <ieee754.h>
+
+#ifdef __STDC__
+long
+__lroundl (long double x)
+#else
+long
+__lroundl (x)
+     long double x;
+#endif
+{
+  double xh, xl;
+  long res, hi, lo;
+
+  ldbl_unpack (x, &xh, &xl);
+
+  /* Limit the range of values handled by the conversion to long.
+     We do this because we aren't sure whether that conversion properly
+     raises FE_INVALID.  */
+  if (
+#if __LONG_MAX__ == 2147483647
+      __builtin_expect
+      ((__builtin_fabs (xh) <= (double) __LONG_MAX__ + 2), 1)
+#else
+      __builtin_expect
+      ((__builtin_fabs (xh) <= -(double) (-__LONG_MAX__ - 1)), 1)
+#endif
+#if !defined (FE_INVALID)
+      || 1
+#endif
+    )
+    {
+#if __LONG_MAX__ == 2147483647
+      long long llhi = (long long) xh;
+      if (llhi != (long) llhi)
+	hi = llhi < 0 ? -__LONG_MAX__ - 1 : __LONG_MAX__;
+      else
+	hi = llhi;
+      xh -= hi;
+#else
+      if (__builtin_expect ((xh == -(double) (-__LONG_MAX__ - 1)), 0))
+	{
+	  /* When XH is 9223372036854775808.0, converting to long long will
+	     overflow, resulting in an invalid operation.  However, XL might
+	     be negative and of sufficient magnitude that the overall long
+	     double is in fact in range.  Avoid raising an exception.  In any
+	     case we need to convert this value specially, because
+	     the converted value is not exactly represented as a double
+	     thus subtracting HI from XH suffers rounding error.  */
+	  hi = __LONG_MAX__;
+	  xh = 1.0;
+	}
+      else
+	{
+	  hi = (long) xh;
+	  xh -= hi;
+	}
+#endif
+      ldbl_canonicalize (&xh, &xl);
+
+      lo = (long) xh;
+
+      /* Peg at max/min values, assuming that the above conversions do so.
+         Strictly speaking, we can return anything for values that overflow,
+         but this is more useful.  */
+      res = hi + lo;
+
+      /* This is just sign(hi) == sign(lo) && sign(res) != sign(hi).  */
+      if (__builtin_expect (((~(hi ^ lo) & (res ^ hi)) < 0), 0))
+	goto overflow;
+
+      xh -= lo;
+      ldbl_canonicalize (&xh, &xl);
+
+      hi = res;
+      if (xh > 0.5)
+	{
+	  res += 1;
+	}
+      else if (xh == 0.5)
+	{
+	  if (xl > 0.0 || (xl == 0.0 && res >= 0))
+	    res += 1;
+	}
+      else if (-xh > 0.5)
+	{
+	  res -= 1;
+	}
+      else if (-xh == 0.5)
+	{
+	  if (xl < 0.0 || (xl == 0.0 && res <= 0))
+	    res -= 1;
+	}
+
+      if (__builtin_expect (((~(hi ^ (res - hi)) & (res ^ hi)) < 0), 0))
+	goto overflow;
+
+      return res;
+    }
+  else
+    {
+      if (xh > 0.0)
+	hi = __LONG_MAX__;
+      else if (xh < 0.0)
+	hi = -__LONG_MAX__ - 1;
+      else
+	/* Nan */
+	hi = 0;
+    }
+
+overflow:
+#ifdef FE_INVALID
+  feraiseexcept (FE_INVALID);
+#endif
+  return hi;
+}
+
+long_double_symbol (libm, __lroundl, lroundl);