Initial commit

first/cc/blinky.c

@@ -0,0 +1,31 @@
+// let's write blinky.c
+
+#define LED_ADDR ((volatile char*)0xC000)
+
+#define led_write(x) (*LED_ADDR = (x))
+
+#define CYCLES_PER_MS 6666  // ish
+
+void busy_sleep_1ms() {
+  for (int i = 0; i < CYCLES_PER_MS; ++i) {
+    // nothing
+  }
+}
+
+/** waits a general amount of time */
+void busy_sleep(int ms) {
+  for (int i = 0; i < ms; ++i) {
+    busy_sleep_1ms();
+  }
+}
+
+int main() {
+  int onoff = 0;
+  while (1) {
+    led_write(onoff);
+    busy_sleep(100);
+    onoff++;
+  }
+
+  return 0;  // actually unreachable
+}