fernlader2/Qcommon.c

#include <stdint.h>

#define COM1_BASE_PORT 0x3F8

static inline uint8_t
inb(uint16_t port)
{
	uint8_t data;
	__asm__ ("inb %%dx, %%al" : "=a"(data) : "d"(port));
	return data;
}

static inline void
outb(uint16_t port, uint8_t data)
{
	__asm__ ("outb %%al, %%dx" :: "a"(data), "d"(port));
}

void serial_write_char(char c)
{
	while (1) {
		int line_status = inb(COM1_BASE_PORT + 5);
		if (line_status & 0x20) {
			break;
		}
	}
	outb(COM1_BASE_PORT, c);
}

void serial_write(const char *msg)
{
	for (const char *c = msg; *c; c++) {
		outb(0xE9, *c);
		//serial_write_char(*c);
	}
}

extern void writechar();

void
main()
{
	serial_write("init\r\n");
	writechar();
	serial_write("foo\r\n");
	for (;;) {
		//__asm__ ("hlt" :);
	}
}