PCI, Serial, Shell improvements (VGA is broken)

kernel/drivers/serial.c

@@ -0,0 +1,36 @@
+#pragma once
+#include "../../arch/i386/asm.c"
+
+#define COM1 (0x3F8)
+
+int serial_init() {
+   outb(COM1 + 1, 0x01);  
+   outb(COM1 + 3, 0x80);  
+   outb(COM1 + 0, 0x03);  
+   outb(COM1 + 1, 0x00);  
+   outb(COM1 + 3, 0x03);  
+   outb(COM1 + 2, 0xC7);  
+   outb(COM1 + 4, 0x0B); 
+   outb(COM1 + 4, 0x0F);
+   return 0;
+}
+
+int serial_has_tx() {
+   return inb(COM1 + 5) & 0x20;
+}
+
+int serial_has_rx() {
+   return inb(COM1 + 5) & 1;
+}
+
+void serial_tx(char a) {
+   while (serial_has_tx() == 0);
+
+   outb(COM1,a);
+}
+
+char serial_rx() {
+   while (serial_has_rx() == 0);
+
+   return inb(COM1);
+}