add shift support

finally get rid of the defined but not used warning.

kernel/Devices/keyboard.c

@@ -12,6 +12,9 @@ static irq_callback_t kbd_callback;
 static volatile int flag = 0;
 static uint8_t last_key;
 
+static uint8_t lshift_flag = 0;
+static uint8_t rshift_flag = 0;
+
 
 // The normal letters numbers and punctuation symbols in scan set 1
 static const char normal_map[] = {
@@ -62,9 +65,26 @@ uint32_t keyboard_handle_irq()
 	uint8_t scancode = inb(0x60);
 
 	if (!(scancode & 0x80)) {
-		flag = 1;
-		last_key = normal_map[scancode];
-		printf("%c", last_key);
+		if (scancode == LSHIFT) {
+			lshift_flag = 1;
+		} else if (scancode == RSHIFT) {
+			rshift_flag = 1;
+		} else {
+			if (lshift_flag || rshift_flag) {
+				last_key = shift_map[scancode];
+			} else {
+				last_key = normal_map[scancode];
+			}
+			flag = 1;
+			printf("%c", last_key);
+		}
+	} else {
+		scancode &= ~0x80;
+		if (scancode == LSHIFT) {
+			lshift_flag = 0;
+		} else if (scancode == RSHIFT) {
+			rshift_flag = 0;
+		}
 	}
 
 	i8259_send_eoi(KEYBOARD_IRQ);

kernel/Devices/keyboard.h

@@ -5,6 +5,9 @@
 
 #define KEYBOARD_IRQ 1
 
+#define LSHIFT 0x2a
+#define RSHIFT 0x36
+
 uint32_t keyboard_init();
 
 uint32_t keyboard_handle_irq();