limine/common/drivers/serial.s2.c

47 lines
832 B
C

#if defined (BIOS)
#include <stdint.h>
#include <stddef.h>
#include <stdbool.h>
#include <drivers/serial.h>
#include <sys/cpu.h>
#include <lib/misc.h>
static bool serial_initialised = false;
static void serial_initialise(void) {
if (serial_initialised) {
return;
}
// Init com1
outb(0x3f8 + 3, 0x00);
outb(0x3f8 + 1, 0x00);
outb(0x3f8 + 3, 0x80);
outb(0x3f8 + 0, 0x0c); // 9600 baud
outb(0x3f8 + 1, 0x00);
outb(0x3f8 + 3, 0x03);
outb(0x3f8 + 2, 0xc7);
outb(0x3f8 + 4, 0x0b);
serial_initialised = true;
}
void serial_out(uint8_t b) {
serial_initialise();
while ((inb(0x3f8 + 5) & 0x20) == 0);
outb(0x3f8, b);
}
int serial_in(void) {
serial_initialise();
if ((inb(0x3f8 + 5) & 0x01) == 0) {
return -1;
}
return inb(0x3f8);
}
#endif