update

drivers/graphics/vgable/src/main.rs

@@ -1,6 +1,8 @@
 #![no_std]
 #![no_main]
 
+use core::ptr;
+
 use able_graphics_library::display::parse_display_string;
 
 const VGA_ADDRESS: *mut u8 = 0xB8000 as *mut u8;
@@ -10,7 +12,7 @@ fn start() {
     // TODO: Initialize the VGA hardware and configure it to the desired video mode
     // (e.g. 640x480, 800x600, etc.).
 
-    let result = parse_display_string("680x480x32@60");
+    let result = parse_display_string("680x480x16@60");
     use able_graphics_library::display::DisplayError::*;
     match result {
         Ok(display) => {
@@ -90,4 +92,28 @@ impl<'a> VGAState<'a> {
         self.set_vga_mode(self.mode)
         // initalize the graphics lib to be usable
     }
+    unsafe fn set_register(address: u16, value: u8) -> Result<(), VGAError> {
+        let address_ptr = address as *mut u8;
+        let value_ptr = value as u8;
+
+        // TODO: check if this works
+        ptr::write_volatile(address_ptr, value_ptr);
+        let read_value = Self::read_register(address);
+        if read_value != value {
+            return Err(VGAError::WrittenValueNotReadValue);
+        }
+        Ok(())
+    }
+    unsafe fn read_register(address: u16) -> u8 {
+        let address_ptr = address as *mut u8;
+
+        ptr::read_volatile(address_ptr)
+    }
+}
+
+pub enum VgaRegister {}
+
+pub enum VGAError {
+    /// The value written is not the same as the value read
+    WrittenValueNotReadValue,
 }