From 46a1639990c7e696181196b8120cf68571e239ab Mon Sep 17 00:00:00 2001
From: John <j@soft.fish>
Date: Thu, 25 Jul 2024 23:59:41 -0500
Subject: [PATCH] sample-code: Have fun with random number generators

---
 sample-code/rand.cl | 37 +++++++++++++++++++++++++++++++++++++
 1 file changed, 37 insertions(+)
 create mode 100644 sample-code/rand.cl

diff --git a/sample-code/rand.cl b/sample-code/rand.cl
new file mode 100644
index 0000000..4915e5b
--- /dev/null
+++ b/sample-code/rand.cl
@@ -0,0 +1,37 @@
+//! Pseudo-random number generation using a LFSR algorithm
+
+static state: u64 = 0xdeadbeefdeadbeef;
+
+pub fn seed(seed: u64) {
+    state = seed;
+}
+
+pub fn lfsr_next() {
+    state ^= state >> 7;
+    state ^= state << 9;
+    state ^= state >> 13;
+}
+
+/// Returns a pseudorandom byte
+pub fn rand() -> u8 {
+    for _ in 0..8 {
+        lfsr_next()
+    }
+    state & 0xff
+}
+
+// Prints a maze out of diagonal box drawing characters, ['╲', '╱']
+fn mazel(width: u64, height: u64) {
+    let walls = ['\u{2571}', '\u{2572}'];
+    rand_rect(width, height, walls)
+}
+
+// Prints a rectangle with the provided walls
+fn rand_rect(width: u64, height: u64, walls: [char; 2]) {
+    for _ in 0..height {
+        for _ in 0..width {
+            print(walls[rand() % 2])
+        }
+        println()
+    }
+}