1 files changed, 14 insertions, 0 deletions
diff --git a/arch/random.h b/arch/random.h
new file mode 100644
index 0000000..ad65660
--- /dev/null
+++ b/arch/random.h
@@ -0,0 +1,14 @@
+// tk-random.h: Smaller pseudo-random function(s).
+// Copyright (C) 2015-2023 Selene ToyKeeper
+// SPDX-License-Identifier: GPL-3.0-or-later
+#pragma once
+
+uint8_t pgm_rand() {
+    static uint16_t offset = 255;
+    // loop through ROM space, but avoid the first 256 bytes
+    // because the beginning tends to have a big ramp which
+    // doesn't look very random at all
+    offset = ((offset + 1) & 0x3ff) | 0x0100;
+    return pgm_read_byte(offset);
+}
+