add more modifier keys

kernel/Devices/keyboard.c

@@ -69,6 +69,8 @@ uint32_t keyboard_handle_irq()
 			lshift_flag = 1;
 		} else if (scancode == RSHIFT) {
 			rshift_flag = 1;
+		} else if (scancode == LALT) {
+
 		} else {
 			if (lshift_flag || rshift_flag) {
 				last_key = shift_map[scancode];

kernel/Devices/keyboard.h

@@ -7,6 +7,11 @@
 
 #define LSHIFT 0x2a
 #define RSHIFT 0x36
+#define LALT 0x38
+#define CAPSLOCK 0x3a
+#define BACKSPACE 0x0e
+
+#define MODIFIER (LSHIFT || RSHIFT || LALT )
 
 uint32_t keyboard_init();