Add strcmp and readline

utils.c

@@ -1,6 +1,6 @@
-#include <stdint.h>
-#include "uart.h"
 #include "clock.h"
+#include "uart.h"
+#include <stdint.h>
 
 // K&R inspirated
 
@@ -71,3 +71,30 @@ void printclock()
 		puts(" Hz\n");
 	}
 }
+
+int readline(char *buf, int maxlen)
+{
+	int num = 0;
+	while (num < maxlen - 1) {
+		char c = uart_recv();
+		// It seems like screen sends \r when I press enter
+		if (c == '\n' || c == '\0' || c == '\r') {
+			break;
+		}
+		buf[num] = c;
+		num++;
+	}
+	buf[num] = '\0';
+	return num;
+}
+
+// Returns <0 if s1<s2, 0 if s1==s2, >0 if s1>s2
+int strcmp(const char s1[], const char s2[])
+{
+    int i;
+    for (i = 0; s1[i] == s2[i]; i++) {
+        if (s1[i] == '\0')
+            return 0;
+    }
+    return s1[i] - s2[i];
+}

utils.h

@@ -6,3 +6,5 @@ void reverse(char s[]);
 void itoa(unsigned int n, char s[]);
 void printdec(unsigned int d);
 void printclock();
+int strcmp(const char s1[], const char s2[]);
+int readline(char *buf, int maxlen);