; Helpers for frame buffer which pretty much have to to be 
; written in asm


; COM1 Base Port
%define SERIAL_COM1_BASE 				0x3F8

%define SERIAL_DATA_PORT(base) 			(base)
%define SERIAL_FIFO_COMMAND_PORT(base) 	(base+2)
%define SERIAL_LINE_COMMAND_PORT(base) 	(base+3)
%define SERIAL_MODEM_COMMAND_PORT(base) (base+4)
%define SERIAL_LINE_STATUS_PORT(base) 	(base+5)

%define SERIAL_DATA_
global serial_control
global serial_read_buffer

serial_control:
	push ebp
	mov ebp, esp
	add esp, 0xc 	; ebp + 2 local vars (32-bit kernel)

	mov al, [esp+8]
	mov dx, [esp+4]
	out dx, al

	mov esp, ebp
	pop ebp
	ret

; Read byte from serial port
serial_read_buffer:
	push ebp
	mov ebp, esp
	push ebx

	xor eax, eax
	mov dx, [esp + 4] 	; grab the address of the targeted port
	in al, dx 			; read byte from the port 

	mov esp, ebp
	pop ebx
	pop ebp
	ret