new OS

kernel/serial.c

@@ -0,0 +1,20 @@
+#include "io.h"
+
+#define COM1 0x3F8
+
+void serial_init(void) {
+    outb(COM1 + 1, 0x00); // Disable interrupts
+    outb(COM1 + 3, 0x80); // Enable DLAB
+    outb(COM1 + 0, 0x03); // Set baud rate to 38400
+    outb(COM1 + 1, 0x00);
+    outb(COM1 + 3, 0x03); // 8 bits, no parity, one stop bit
+    outb(COM1 + 2, 0xC7); // Enable FIFO, clear, 14-byte threshold
+    outb(COM1 + 4, 0x0B); // IRQs enabled, RTS/DSR set
+}
+
+void serial_write(const char *str) {
+    while (*str) {
+        while (!(inb(COM1 + 5) & 0x20)); // Wait for the transmitter holding register to be empty
+        outb(COM1, *str++);
+    }
+}