#include "../includes/io.h"
/* Sets the speed of the data being sent. The default speed of a serial port
   is 115,200 bits/s. The argument is a divisor of that number, hence the resulting
   speed becomes 115,200 / divisor bits/s.
*/
void set_serial_baud_rate(unsigned short com, unsigned short divisor){
	outb(com + 3, 0x80);//SERIAL_LINE_ENABLE_DLAB);
	
	outb(com, (divisor >> 8) & 0x00FF);
	
	outb(com, divisor & 0x00FF);
}

void configure_serial_line(unsigned short com){

	// Configuring the Line
	/* d: 		Enables (1) or disables (0) DLAB
	   b: 		Break if controls is enabled (1)
	   parity: 	The number of parity bits to use
	   s: 		The number of stop bits to use (0 = One Stop, 1 = 1.5 or 2 stops)
	   dl: 		Describes the langth of the data
	   
	   Bit:		| 7 | 6 | 5 4 3 | 2 | 1 0 |
	   Content: | d | b | parity| s | dl  |
	   Value:	| 0 | 0 | 0 0 0 | 0 | 1 1 | = 0x03
	*/
	outb(com + 3, 0x03);
	// Configuring the Buffers
	/* lvl: How many bytes should be stored in the FIFO buffers
	   bs: 	If the buffers should be 16 or 64 bytes large
	   r:	Reserved
	   dma:	How the serial port data should be accessed
	   clt: Clear the transmission FIFO buffer
	   clr: Clear the reciever FIFO buffer
	   e:	If the FIFO bufffer should be enabled or not
	   
	   Bit:		| 7 6 | 5 | 4 | 3  | 2  | 1  | 0 |
	   Content:	| lvl | bs| r | dma| clt| clr| e |
	   Value: 	| 1 1 | 0 | 0 | 0  | 1  | 1  | 1 |
	*/
	outb(com + 2, 0xC7);	
	// Confirgure the Modem
	outb(com + 4, 0x03);
}
/* @return 0 if the FIFO is not empty
		   1 if the FIFO is empty
*/
int serial_transmit_fifo_empty(unsigned int com){
	// 0x20 = 0010 0000
	return inb(com + 5) & 0x20;
}

void write_to_com(unsigned int com, char* msg){
	for(int i = 0; msg[i] != '\0'; i++){
		while(serial_transmit_fifo_empty(com) == 0);
		
		outb(com, (char) msg[i]);
	}
}