Add in random(), make rand use that under the hood. Fix the

include file so folks know random is now there.

1 files changed, 36 insertions, 0 deletions

diff --git a/libc/stdlib/random.c b/libc/stdlib/random.c
new file mode 100644
index 000000000..c040ce455
--- /dev/null
+++ b/libc/stdlib/random.c
@@ -0,0 +1,36 @@
+#include <stdlib.h>
+
+/*
+ * This generator is a combination of three linear congruential generators
+ * with periods or 2^15-405, 2^15-1041 and 2^15-1111. It has a period that
+ * is the product of these three numbers.
+ */
+
+static long int seed1 = 1;
+static long int seed2 = 1;
+static long int seed3 = 1;
+
+#define CRANK(a,b,c,m,s) 	\
+	q = s/a;		\
+	s = b*(s-a*q) - c*q;	\
+	if(s<0) s+=m;
+
+long int random()
+{
+	register long int q;
+
+	CRANK(206, 157, 31, 32363, seed1);
+	CRANK(217, 146, 45, 31727, seed2);
+	CRANK(222, 142, 133, 31657, seed3);
+
+	return seed1 ^ seed2 ^ seed3;
+}
+
+void srandom(unsigned int seed)
+{
+	seed &= RAND_MAX;
+	seed1 = seed % 32362 + 1;
+	seed2 = seed % 31726 + 1;
+	seed3 = seed % 31656 + 1;
+}
+