20060303a

1 files changed, 30 insertions, 0 deletions

diff --git a/libmath/fdlibm/s_isnan.c b/libmath/fdlibm/s_isnan.c
new file mode 100644
index 00000000..d9a5bf97
--- /dev/null
+++ b/libmath/fdlibm/s_isnan.c
@@ -0,0 +1,30 @@
+/* derived from /netlib/fdlibm */
+
+/* @(#)s_isnan.c 1.3 95/01/18 */
+/*
+ * ====================================================
+ * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
+ *
+ * Developed at SunSoft, a Sun Microsystems, Inc. business.
+ * Permission to use, copy, modify, and distribute this
+ * software is freely granted, provided that this notice 
+ * is preserved.
+ * ====================================================
+ */
+
+/*
+ * isnan(x) returns 1 is x is nan, else 0;
+ * no branching!
+ */
+
+#include "fdlibm.h"
+
+	int isnan(double x)
+{
+	int hx,lx;
+	hx = (__HI(x)&0x7fffffff);
+	lx = __LO(x);
+	hx |= (unsigned)(lx|(-lx))>>31;	
+	hx = 0x7ff00000 - hx;
+	return ((unsigned)(hx))>>31;
+}