1 files changed, 48 insertions, 0 deletions
diff --git a/usr/src/lib/libm/common/C/isnan.c b/usr/src/lib/libm/common/C/isnan.c
new file mode 100644
index 0000000000..5df577c863
--- /dev/null
+++ b/usr/src/lib/libm/common/C/isnan.c
@@ -0,0 +1,48 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License (the "License").
+ * You may not use this file except in compliance with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or http://www.opensolaris.org/os/licensing.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+/*
+ * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
+ */
+/*
+ * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
+ * Use is subject to license terms.
+ */
+
+#pragma weak isnan = __isnan
+#pragma weak _isnan = __isnan
+#pragma weak _isnand = __isnan
+#pragma weak isnand = __isnan
+
+#include "libm.h"
+
+/*
+ * The following implementation assumes fast 64-bit integer arith-
+ * metic.  This is fine for sparc because we build libm in v8plus
+ * mode.  It's also fine for sparcv9 and amd64.  For x86, it would
+ * be better to use 32-bit code, but we have assembly for x86.
+ */
+int
+__isnan(double x) {
+	long long	llx;
+
+	llx = *(long long *)&x & ~0x8000000000000000ull;
+	return ((unsigned long long)(0x7ff0000000000000ll - llx) >> 63);
+}