matter.c

commit 51db4d29384febdde2cbbade26b4a73beed0d764
parent 5d0c7b7fd05f0d0d976119a159c830eebfd255a7
Author: Yersa Nordman <finwo@pm.me>
Date:   Fri, 19 Jun 2020 14:16:14 +0200

Added prng/rand

Diffstat:
A
include/stdlib.h
 | 
9
+++++++++
A
src/prng/rand.c
 | 
13
+++++++++++++

2 files changed, 22 insertions(+), 0 deletions(-)
diff --git a/include/stdlib.h b/include/stdlib.h
@@ -0,0 +1,9 @@
+#ifndef _STDLIB_H_
+#define _STDLIB_H_
+
+#include <stdint.h>
+
+void srand(unsigned s);
+int rand(void);
+
+#endif // _STDLIB_H_
diff --git a/src/prng/rand.c b/src/prng/rand.c
@@ -0,0 +1,13 @@
+#include <stdlib.h>
+#include <stdint.h>
+
+static uint64_t seed;
+
+void srand(unsigned s) {
+	seed = s-1;
+}
+
+int rand(void) {
+	seed = 6364136223846793005ULL*seed + 1;
+	return seed>>33;
+}