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diff --git a/sysdeps/m68k/fpu/logb.c b/sysdeps/m68k/fpu/logb.c
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+/* Copyright (C) 1991, 1992, 1993, 1994, 1995 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 Library General Public License as
+published by the Free Software Foundation; either version 2 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
+Library General Public License for more details.
+
+You should have received a copy of the GNU Library General Public
+License along with the GNU C Library; see the file COPYING.LIB.  If
+not, write to the Free Software Foundation, Inc., 675 Mass Ave,
+Cambridge, MA 02139, USA.  */
+
+#include <ansidecl.h>
+#include <math.h>
+
+#ifdef	__GNUC__
+
+/* Return the base 2 signed integral exponent of X.  */
+
+double
+DEFUN(__logb, (x), double x)
+{
+  if (__isnan (x))
+    return x;
+  if (__isinf (x))
+    return fabs (x);
+
+  if (x == 0.0)
+    asm ("flog2%.x %0, %0" : "=f" (x) : "0" (x));
+  else
+    asm ("fgetexp%.x %0, %0" : "=f" (x) : "0" (x));
+
+  return x;
+}
+
+weak_alias (__logb, logb)
+
+#else
+#include <sysdeps/ieee754/logb.c>
+#endif