scan code to ascii

src/kernel.c

@@ -6,7 +6,7 @@
 
 void keyboard_handler(const keyboard_event_t* event)
 {
-    if (event->pressed)
+    if (event->pressed && event->ascii)
     {
         vga_print_char(event->ascii);
     }

src/keyboard.c

@@ -19,6 +19,14 @@ unsigned const char us_keymap[128] = {
     0,   0,   '-', 0,   0,    0,   '+', 0,    0,   0,   0,    0,   0,   0,   0,    0,    0,   0,
 };
 
+unsigned const char us_keymap_shift[128] = {
+    0,   27,  '!', '@', '#', '$', '%', '^', '&', '*', '(',  ')', '_', '+', '\b', '\t', 'Q', 'W',
+    'E', 'R', 'T', 'Y', 'U', 'I', 'O', 'P', '{', '}', '\n', 0,   'A', 'S', 'D',  'F',  'G', 'H',
+    'J', 'K', 'L', ':', '"', '~', 0,   '|', 'Z', 'X', 'C',  'V', 'B', 'N', 'M',  '<',  '>', '?',
+    0,   '*', 0,   ' ', 0,   0,   0,   0,   0,   0,   0,    0,   0,   0,   0,    0,    0,   0,
+    0,   0,   '-', 0,   0,   0,   '+', 0,   0,   0,   0,    0,   0,   0,   0,    0,    0,   0,
+};
+
 bool shift = false;
 bool caps_lock = false;
 
@@ -26,6 +34,23 @@ bool caps_lock = false;
 static keyboard_handler_t keyboard_handlers[KEYBOARD_HANDLERS_LENGTH];
 static int handler_index = 0;
 
+char scan_code_to_ascii(uint8_t scan_code)
+{
+    if (scan_code >= 128)
+    {
+        return 0;
+    }
+
+    if ((!caps_lock && shift) || (caps_lock && !shift))
+    {
+        return us_keymap_shift[scan_code];
+    }
+    else
+    {
+        return us_keymap[scan_code];
+    }
+}
+
 void handle_keyboard(const isr_frame_t* frame)
 {
     uint8_t code = inb(0x60);
@@ -55,7 +80,7 @@ void handle_keyboard(const isr_frame_t* frame)
             .pressed = pressed,
             .caps_lock = caps_lock,
             .shift = shift,
-            .ascii = us_keymap[scan_code],
+            .ascii = scan_code_to_ascii(scan_code),
         };
 
         for (int i = 0; i < handler_index; i++)

src/keyboard.h

@@ -16,3 +16,4 @@ typedef void (*keyboard_handler_t)(const keyboard_event_t*);
 
 void init_keyboard();
 void register_keypress_handler(keyboard_handler_t handler);
+char scan_code_to_ascii(uint8_t scan_code);