LAB 4 IS DONE.

lab/lib/console.c

@@ -0,0 +1,25 @@
+
+#include <inc/string.h>
+#include <inc/lib.h>
+
+void
+cputchar(int ch)
+{
+	char c = ch;
+
+	// Unlike standard Unix's putchar,
+	// the cputchar function _always_ outputs to the system console.
+	sys_cputs(&c, 1);
+}
+
+int
+getchar(void)
+{
+	int r;
+	// sys_cgetc does not block, but getchar should.
+	while ((r = sys_cgetc()) == 0)
+		sys_yield();
+	return r;
+}
+
+