1 files changed, 17 insertions, 0 deletions
diff --git a/src/lib9/frand.c b/src/lib9/frand.c
new file mode 100644
index 00000000..841f9685
--- /dev/null
+++ b/src/lib9/frand.c
@@ -0,0 +1,17 @@
+#include	<u.h>
+#include	<libc.h>
+
+#define	MASK	0x7fffffffL
+#define	NORM	(1.0/(1.0+MASK))
+
+double
+p9frand(void)
+{
+	double x;
+
+	do {
+		x = lrand() * NORM;
+		x = (x + lrand()) * NORM;
+	} while(x >= 1);
+	return x;
+}