From a8a775abbe711d4442004264cac4cc84aed9cf6a Mon Sep 17 00:00:00 2001
From: David du Colombier <0intro@gmail.com>
Date: Fri, 1 Sep 2017 22:51:14 +0200
Subject: lib9: import frand function from Plan 9

Fixes #15.
---
 src/lib9/frand.c | 17 +++++++++++++++++
 src/lib9/mkfile  |  1 +
 2 files changed, 18 insertions(+)
 create mode 100644 src/lib9/frand.c

(limited to 'src')

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;
+}
diff --git a/src/lib9/mkfile b/src/lib9/mkfile
index 4bbd0f8b..8f7283ef 100644
--- a/src/lib9/mkfile
+++ b/src/lib9/mkfile
@@ -102,6 +102,7 @@ LIB9OFILES=\
 	execl.$O\
 	exitcode.$O\
 	fcallfmt.$O\
+	frand.$O\
 	get9root.$O\
 	getcallerpc-$OBJTYPE.$O\
 	getenv.$O\
-- 
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