keyboard driver

src/keyboard.c

@@ -0,0 +1,72 @@
+#include "keyboard.h"
+#include "idt.h"
+#include "kernel.h"
+#include "vga.h"
+#include <stdbool.h>
+#include <stdint.h>
+
+#define SCANCODE_LEFT_SHIFT 42
+#define SCANCODE_RIGHT_SHIFT 54
+#define SCANCODE_CAPS_LOCK 58
+
+#define KEYBOARD_HANDLERS_LENGTH 32
+
+bool shift = false;
+bool caps_lock = false;
+
+// todo(nub): make dynamic when a memory allocator is implemented
+static keyboard_handler_t keyboard_handlers[KEYBOARD_HANDLERS_LENGTH];
+static int handler_index = 0;
+
+void handle_keyboard(isr_frame_t* frame)
+{
+    uint8_t code = inb(0x60);
+    uint8_t scan_code = code & 0x7F;
+    bool pressed = (code & 0x80) == 0;
+
+    switch (scan_code)
+    {
+    case SCANCODE_LEFT_SHIFT:
+    case SCANCODE_RIGHT_SHIFT:
+    {
+        shift = pressed;
+        break;
+    }
+    case SCANCODE_CAPS_LOCK:
+    {
+        if (pressed)
+        {
+            caps_lock = !caps_lock;
+        }
+        break;
+    }
+    default:
+    {
+        keyboard_event_t event = { .scan_code = scan_code, .pressed = pressed, .caps_lock = caps_lock, .shift = shift };
+
+        for (int i = 0; i < handler_index; i++)
+        {
+            keyboard_handlers[i](&event);
+        }
+    }
+    }
+}
+
+void register_keypress_handler(keyboard_handler_t handler)
+{
+    // todo(nub31): remove when a memory allocator is implemented and keyboard_handlers is a dynamic list
+    if (handler_index >= KEYBOARD_HANDLERS_LENGTH)
+    {
+        vga_print_error();
+        vga_print(" Maximum keyboard handlers reached\n");
+        kpanic();
+    }
+
+    keyboard_handlers[handler_index] = handler;
+    handler_index += 1;
+}
+
+void init_keyboard()
+{
+    register_irq_handler(1, handle_keyboard);
+}