1 files changed, 66 insertions, 0 deletions
diff --git a/blink.zig b/blink.zig
new file mode 100644
index 0000000..4444427
--- /dev/null
+++ b/blink.zig
@@ -0,0 +1,66 @@
+const std = @import("std");
+
+const DDRB = @as(*volatile u8, @ptrFromInt(0x24));
+const PORTB = @as(*volatile u8, @ptrFromInt(0x25));
+
+const DELAY = 100;
+
+pub export fn delay(n: u32) void {
+    var i: u32 = 0;
+    while (i < n) : (i += 1) {
+        asm volatile ("nop" ::: "memory");
+    }
+}
+
+pub export fn blink(n: u32) void {
+    var i: u32 = 0;
+    DDRB.* = DDRB.* | (1 << 5);
+
+    while (i < n) : (i += 1) {
+        // Toggle PB5
+        PORTB.* ^= @as(u8, 1 << 5);
+        delay(100_000);
+        PORTB.* ^= @as(u8, 1 << 5);
+        delay(200_000);
+    }
+}
+
+pub export fn collatz(na: u32) u32 {
+    var n: u32 = na;
+    var c: u32 = 0;
+
+    while (n > 1) : (c += 1) {
+        if (n % 2 == 0) {
+            n /= 2;
+        } else {
+            n = n + n + n + 1;
+        }
+    }
+
+    return c;
+}
+
+pub export fn main() void {
+    var i: u32 = 0;
+    while (true) : (i += 1) {
+        const c = collatz(i);
+        blink(c);
+        delay(500_000);
+    }
+}
+
+pub export fn abort() void {
+    // Set PB5 (pin 13) as output
+    DDRB.* = DDRB.* | (1 << 5);
+
+    while (true) {
+        // Toggle PB5
+        PORTB.* ^= @as(u8, 1 << 5);
+
+        // Simple delay
+        var i: usize = 0;
+        while (i < DELAY) : (i += 1) {
+            asm volatile ("nop" ::: "memory");
+        }
+    }
+}