Initial commit

uart/testtx.c

@@ -0,0 +1,32 @@
+#define UART_BASE 0xc010
+#define UART_DATA   ((volatile char*) (UART_BASE + 0x00))
+#define UART_STATUS ((volatile char*) (UART_BASE + 0x02))
+
+#define UART_STATUS_RXNE_pos 1
+#define UART_STATUS_RXNE_msk (1 << UART_STATUS_RXNE_pos)
+#define UART_STATUS_TXE_pos  0
+#define UART_STATUS_TXE_msk  (1 << UART_STATUS_TXE_pos)
+
+const char hello[] = "Hello, world!";
+
+int uart_tx_available() {
+  return (*UART_STATUS & UART_STATUS_TXE_msk) != 0;
+}
+
+void uart_send(const char* data, int len) {
+  for (int i = 0; i < len; ++i) {
+    while (!uart_tx_available()) {
+    }
+
+    *UART_DATA = data[i];
+  }
+}
+
+int main() {
+  uart_send(hello, sizeof(hello));
+
+  while (1) {
+  }
+
+  // never returns
+}