import trunc()/truncf() for ISO C requirements, otherwise fortran can hit infinite loops when it generates builtins+trunc() substitutes

1 files changed, 58 insertions, 0 deletions

diff --git a/libm/s_trunc.c b/libm/s_trunc.c
new file mode 100644
index 000000000..8a4f5ae05
--- /dev/null
+++ b/libm/s_trunc.c
@@ -0,0 +1,58 @@
+/* Truncate argument to nearest integral value not larger than the argument.
+   Copyright (C) 1997, 1998 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
+
+   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 "math_private.h"
+
+
+libm_hidden_proto(trunc)
+double
+trunc (double x)
+{
+  int32_t i0, j0;
+  u_int32_t i1;
+  int sx;
+
+  EXTRACT_WORDS (i0, i1, x);
+  sx = i0 & 0x80000000;
+  j0 = ((i0 >> 20) & 0x7ff) - 0x3ff;
+  if (j0 < 20)
+    {
+      if (j0 < 0)
+	/* The magnitude of the number is < 1 so the result is +-0.  */
+	INSERT_WORDS (x, sx, 0);
+      else
+	INSERT_WORDS (x, sx | (i0 & ~(0x000fffff >> j0)), 0);
+    }
+  else if (j0 > 51)
+    {
+      if (j0 == 0x400)
+	/* x is inf or NaN.  */
+	return x + x;
+    }
+  else
+    {
+      INSERT_WORDS (x, i0, i1 & ~(0xffffffffu >> (j0 - 20)));
+    }
+
+  return x;
+}
+libm_hidden_def(trunc)