Configure the UART sufficiently to actually get the message out.

main.c

@@ -1,11 +1,43 @@
 
-#define U0THR (*((volatile unsigned char *) 0xE000C000)) /* UART0 transmitter holding register */
-#define U0LSR (*((volatile unsigned char *) 0xE000C014)) /* UART0 line status register */
-#define U0THRE ((U0LSR & (1<<5))) /* UART0 transmitter holding register is empty */
+#define UARTBASE 0xE000C000
+
+#define RBR 0x00
+#define THR 0x00
+#define DLL 0x00
+#define DLM 0x04
+#define IER 0x04
+#define IIR 0x08
+#define FCR 0x08
+
+#define LCR 0x0c
+#define LSR 0x14
+#define SCR 0x1c
+#define ACR 0x20
+#define FDR 0x28
+#define TER 0x30
+
+#define REG(x) (((volatile unsigned char *)UARTBASE)[x])
+
+#define U0THRE ((REG(LSR) & (1<<5))) /* UART0 transmitter holding register is empty */
+
+#define PINSEL0 (*((volatile unsigned char *) 0xE002C000))
+
+void init_uart(void)
+{
+	REG(FDR) = 0x10; /* DivAddVal = 0, MulVal = 1 */
+
+	REG(LCR) = 0x80;
+	REG(DLM) = 0x00;
+	REG(DLL) = 0x08; /* 14745600 / (16*115200) */
+	REG(LCR) = 0x13;
+	REG(FCR) = 0x07;
+
+	PINSEL0 = 0x00000005; /* P0.0 and P0.1 assigned to UART */
+}
 
 void putch(char c) {
 	while (!U0THRE);
-	U0THR = c;
+	REG(THR) = c;
 }
 
 void putstr(char *s) {
@@ -13,6 +45,7 @@ void putstr(char *s) {
 }
 
 int main(void) {
+	init_uart();
 	putstr("Your entire life has been a mathematical error... a mathematical error I'm about to correct!\n");
 	return 0;
 }