GitFOSS

@@ -19,6 +19,22 @@ fun kearly(info_ptr: LibBootstrap::StartInfo*)
   # IDT.init
 end
 
+def outb(port : UInt16, value : UInt8)
+  asm (%(outb %al, %dx) : : "a"(value), "Nd"(port))
+end
+
+def set_cursor_position(row : Int32, col : Int32)
+  position = (80 * row + col).to_u16
+
+  # # Write the high byte
+  # outb(0x3D4_u16, 0x0E_u8);
+  # outb(0x3D5_u16, ((position >> 8) & 0xFF).to_u8);
+
+  # # Write the low byte
+  # outb(0x3D4_u16, 0x0F_u8);
+  # outb(0x3D5_u16, (position & 0xFF).to_u8);
+end
+
 def clear_screen
   video_memory = Pointer(UInt8).new(0xB8000_u64)
   screen_size = 80 * 25

@@ -34,11 +50,22 @@ fun kmain
   # IDT.enable_interrupts
   # kprint "Hello from Fluorite."
 
-  asm("cli")
+  message = "[CrystalOS Kernel] Hello from Crystal"
+  
   clear_screen
+  set_cursor_position(0, 0)
 
-  message = "[CrystalOS Kernel] Hello from Crystal\n"
-  puts message
+  _str : Pointer(UInt8) = message.to_unsafe
+  video_memory = Pointer(UInt8).new(0xB8000_u64)
+  i = 0
+  ch = _str.value
+  while ch > 0
+    ch = (_str + i).value
+    break if ch == 0
+    (video_memory + (i * 2)).value = ch
+    (video_memory + (i * 2) + 1).value = 0xB0_u8
+    i += 1
+  end
 
   while true
   end