20090401-2350

1 files changed, 69 insertions, 0 deletions

diff --git a/libkern/nan-spim.c b/libkern/nan-spim.c
new file mode 100644
index 00000000..2152925a
--- /dev/null
+++ b/libkern/nan-spim.c
@@ -0,0 +1,69 @@
+#include <lib9.h>
+
+#define	NANEXP	(2047<<20)
+#define	NANMASK	(2047<<20)
+#define	NANSIGN	(1<<31)
+
+double
+NaN(void)
+{
+	union
+	{
+		double	d;
+		long	x[2];
+	} a;
+
+	a.x[1] = NANEXP;
+	a.x[0] = 1;
+	return a.d;
+}
+
+int
+isNaN(double d)
+{
+	union
+	{
+		double	d;
+		long	x[2];
+	} a;
+
+	a.d = d;
+	if((a.x[1] & NANMASK) != NANEXP)
+		return 0;
+	return !isInf(d, 0);
+}
+
+double
+Inf(int sign)
+{
+	union
+	{
+		double	d;
+		long	x[2];
+	} a;
+
+	a.x[1] = NANEXP;
+	a.x[0] = 0;
+	if(sign < 0)
+		a.x[1] |= NANSIGN;
+	return a.d;
+}
+
+int
+isInf(double d, int sign)
+{
+	union
+	{
+		double	d;
+		long	x[2];
+	} a;
+
+	a.d = d;
+	if(a.x[0] != 0)
+		return 0;
+	if(a.x[1] == NANEXP)
+		return sign >= 0;
+	if(a.x[1] == (NANEXP|NANSIGN))
+		return sign <= 0;
+	return 0;
+}