51 lines
1.1 KiB
C
51 lines
1.1 KiB
C
#include <stdint.h>
|
|
#include <stdbool.h>
|
|
|
|
#define SERIAL_PORT 0x3f8
|
|
|
|
extern uint8_t serial_inb(uint16_t port);
|
|
extern void serial_outb(uint16_t port, uint8_t value);
|
|
|
|
static int serial_received(void) {
|
|
return serial_inb(SERIAL_PORT + 5) & 1;
|
|
}
|
|
|
|
static uint8_t serial_read(void) {
|
|
while (serial_received() == 0);
|
|
return serial_inb(SERIAL_PORT);
|
|
}
|
|
|
|
static int serial_trans_empty(void) {
|
|
return serial_inb(SERIAL_PORT + 5) & 0x20;
|
|
}
|
|
|
|
static void serial_write(uint8_t value) {
|
|
while (!serial_trans_empty());
|
|
serial_outb(SERIAL_PORT, value);
|
|
}
|
|
|
|
// REFERENCE: https://wiki.osdev.org/Serial_Ports
|
|
bool serial_init(void) {
|
|
serial_outb(SERIAL_PORT + 1, 0x00);
|
|
serial_outb(SERIAL_PORT + 3, 0x80);
|
|
serial_outb(SERIAL_PORT + 0, 0x03);
|
|
serial_outb(SERIAL_PORT + 1, 0x00);
|
|
serial_outb(SERIAL_PORT + 3, 0x03);
|
|
serial_outb(SERIAL_PORT + 2, 0xc7);
|
|
serial_outb(SERIAL_PORT + 4, 0x0b);
|
|
serial_outb(SERIAL_PORT + 4, 0x1e);
|
|
serial_outb(SERIAL_PORT + 0, 0xae);
|
|
|
|
if (serial_inb(SERIAL_PORT + 0) != 0xae) {
|
|
return false;
|
|
}
|
|
|
|
serial_outb(SERIAL_PORT + 4, 0x0f);
|
|
return true;
|
|
}
|
|
|
|
// For printf library
|
|
void putchar_(char c) {
|
|
serial_write(c);
|
|
}
|