diff --git a/ChangeLog b/ChangeLog
index 242b5bb83e..e7ce260758 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,8 @@
 2009-08-25  Ulrich Drepper  <drepper@redhat.com>
 
+	* sysdeps/x86_64/fpu/s_signbit.S: New file.
+	* sysdeps/x86_64/fpu/s_signbitf.S: New file.
+
 	* sysdeps/ieee754/dbl-64/wordsize-64/s_lround.c: New file.
 	* sysdeps/ieee754/dbl-64/wordsize-64/s_trunc.c: New file.
 
diff --git a/sysdeps/x86_64/fpu/s_signbit.S b/sysdeps/x86_64/fpu/s_signbit.S
new file mode 100644
index 0000000000..0bfd62e30d
--- /dev/null
+++ b/sysdeps/x86_64/fpu/s_signbit.S
@@ -0,0 +1,27 @@
+/* Return nonzero value if number is negative.
+   Copyright (C) 2009 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Ulrich Drepper <drepper@redha.com>, 2009.
+
+   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 <sysdep.h>
+
+ENTRY(__signbit)
+	pmovmskb %xmm0, %eax
+	andl	$0x80, %eax
+	ret
+END(__signbit)
diff --git a/sysdeps/x86_64/fpu/s_signbitf.S b/sysdeps/x86_64/fpu/s_signbitf.S
new file mode 100644
index 0000000000..f0681d0124
--- /dev/null
+++ b/sysdeps/x86_64/fpu/s_signbitf.S
@@ -0,0 +1,27 @@
+/* Return nonzero value if number is negative.
+   Copyright (C) 2009 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Ulrich Drepper <drepper@redha.com>, 2009.
+
+   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 <sysdep.h>
+
+ENTRY(__signbitf)
+	pmovmskb %xmm0, %eax
+	andl	$0x8, %eax
+	ret
+END(__signbitf)