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-rw-r--r--sysdeps/ieee754/ldbl-128ibm/s_truncl.c119
1 files changed, 119 insertions, 0 deletions
diff --git a/sysdeps/ieee754/ldbl-128ibm/s_truncl.c b/sysdeps/ieee754/ldbl-128ibm/s_truncl.c
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index 0000000000..14544af206
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+++ b/sysdeps/ieee754/ldbl-128ibm/s_truncl.c
@@ -0,0 +1,119 @@
+/* Truncate (toward zero) 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.h>
+#include <math_ldbl_opt.h>
+#include <float.h>
+#include <ieee754.h>
+
+
+#ifdef __STDC__
+long double
+__truncl (long double x)
+#else
+long double
+__truncl (x)
+     long double x;
+#endif
+{
+  static const double TWO52 = 4503599627370496.0L;
+  int mode = fegetround();
+  union ibm_extended_long_double u;
+
+  u.d = x;
+
+  if (fabs (u.dd[0]) < TWO52)
+    {      
+      fesetround(FE_TOWARDZERO);
+      if (u.dd[0] > 0.0)
+	{
+	  u.dd[0] += TWO52;
+	  u.dd[0] -= TWO52;
+	}
+      else if (u.dd[0] < 0.0)
+	{
+	  u.dd[0] = TWO52 - u.dd[0];
+	  u.dd[0] = -(u.dd[0] - TWO52);
+	}
+      u.dd[1] = 0.0;
+      fesetround(mode);
+    }
+  else if (fabs (u.dd[1]) < TWO52 && u.dd[1] != 0.0)
+    {
+      double high, low;
+      /* In this case we have to round the low double and handle any
+         adjustment to the high double that may be caused by rounding
+         (up).  This is complicated by the fact that the high double
+         may already be rounded and the low double may have the
+         opposite sign to compensate.  */
+      if (u.dd[0] > 0.0)
+	{
+	  if (u.dd[1] > 0.0)
+	    {
+	      /* If the high/low doubles are the same sign then simply
+	         round the low double.  */
+	      high = u.dd[0];
+	      low = u.dd[1];
+	    }
+	  else if (u.dd[1] < 0.0)
+	    {
+	      /* Else the high double is pre rounded and we need to
+	         adjust for that.  */
+	      high = nextafter (u.dd[0], 0.0);
+	      low = u.dd[1] + (u.dd[0] - high);
+	    }      
+          fesetround(FE_TOWARDZERO);
+	  low += TWO52;
+	  low -= TWO52;
+          fesetround(mode);
+	}
+      else if (u.dd[0] < 0.0)
+	{
+	  if (u.dd[1] < 0.0)
+	    {
+	      /* If the high/low doubles are the same sign then simply
+	         round the low double.  */
+	      high = u.dd[0];
+	      low = u.dd[1];
+	    }
+	  else if (u.dd[1] > 0.0)
+	    {
+	      /* Else the high double is pre rounded and we need to
+	         adjust for that.  */
+	      high = nextafter (u.dd[0], 0.0);
+	      low = u.dd[1] + (u.dd[0] - high);
+	    }      
+          fesetround(FE_TOWARDZERO);
+	  low = TWO52 - low;
+	  low = -(low - TWO52);
+          fesetround(mode);
+	}
+      u.dd[0] = high + low;
+      u.dd[1] = high - u.dd[0] + low;
+    }
+
+  return u.d;
+}
+
+long_double_symbol (libm, __truncl, truncl);