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path: root/kernel/src/devices/serial.c
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#include <io.h>
#include <serial.h>

void init_serial()
{
	outb(PORT + 1, 0x00); // Disable all interrupts
	outb(PORT + 3, 0x80); // Enable DLAB (set baud rate divisor)
	outb(PORT + 0, 0x03); // Set divisor to 3 (lo byte) 38400 baud
	outb(PORT + 1, 0x00); //                  (hi byte)
	outb(PORT + 3, 0x03); // 8 bits, no parity, one stop bit
	outb(PORT + 2, 0xC7); // Enable FIFO, clear them, with 14-byte threshold
	outb(PORT + 4, 0x0B); // IRQs enabled, RTS/DSR set
}

uint8_t serial_received()
{
	return inb(PORT + 5) & 1;
}

char read_serial()
{
	while (serial_received() == 0)
		;

	return (char)inb(PORT);
}

uint8_t is_transmit_empty()
{
	return inb(PORT + 5) & 0x20;
}

void write_serial(char c)
{
	while (is_transmit_empty() == 0)
		;

	outb(PORT, (uint8_t)c);
}