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This diff has been restricted to the following files: 'main.c'

#
# old_revision [0b05faeb3c5c6294511a5c77018c9c2a6f644535]
# new_revision [7ac10cd34167baa43683a09e9e9e6778e691171d]
#
# patch "main.c"
#  from [0320b79369f77b68526dd563a325920b95e16d18]
#    to [014a6056e25731519db6fc251ceb035b3bcd1c2a]
#
============================================================
--- main.c	0320b79369f77b68526dd563a325920b95e16d18
+++ main.c	014a6056e25731519db6fc251ceb035b3bcd1c2a
@@ -1,18 +1,111 @@
 
-#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 U0DR ((REG(LSR) & (1<<0))) /* UART0 data ready */
+
+#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) {
 	while (*s) putch(*s++);
 }
 
+void putint(unsigned int n) {
+	char s[11];
+	int i;
+
+	i = 10;
+	s[i] = '\0';
+
+	do {
+		s[--i] = n % 10 + '0';
+	} while ((n /= 10) > 0);
+
+	putstr(s+i);
+}
+
+char getch(void) {
+	while (!U0DR);
+	return REG(RBR);
+}
+
+void reply(char *str)
+{
+	putstr(str);
+	putstr("\r\n");
+}
+
+unsigned int count = 0;
+
 int main(void) {
-	putstr("Your entire life has been a mathematical error... a mathematical error I'm about to correct!\n");
+	init_uart();
+	putstr("Your entire life has been a mathematical error... a mathematical error I'm about to correct!\r\n");
+
+	while (1) {
+		char c;
+		putstr("prompt> ");
+		c = getch();
+		if (c == 0x0a)
+			continue;
+		putch(c);
+		putstr("\r\n");
+		switch (c & 0xdf) {
+		case 0x0a:
+		case 0x0d:
+			break;
+		case 'A':
+			reply("apple");
+			break;
+		case 'C':
+			count++;
+			putstr("The current count is ");
+			putint(count);
+			reply(".");
+			break;
+		case 'H':
+		case '?':
+			reply("Help is not available. Try a psychiatrist.");
+			break;
+		default:
+			reply("Unrecognised command.");
+			break;
+		}
+	}
+
 	return 0;
 }