kprintf

kernel/com1.c

@@ -0,0 +1,32 @@
+#include <serial.h>
+#include <com1.h>
+
+#define COM1 0x3f8
+
+void com1_init(void) {
+  serial_outb(COM1 + 1, 0x00); // no intr
+  serial_outb(COM1 + 3, 0x80); // enable DLAB
+  serial_outb(COM1 + 0, 0x01); // 115200 baudrate
+  serial_outb(COM1 + 1, 0x00);
+  serial_outb(COM1 + 3, 0x03); // 8N1
+  serial_outb(COM1 + 2, 0xc7); // fifo
+  serial_outb(COM1 + 4, 0x0b); // irqs enabled, rts/dsr set
+}
+
+int32 com1_is_ready(void) {
+  return serial_inb(COM1 + 5) & 0x20;
+}
+
+void com1_putch(char c) {
+  while (!com1_is_ready());
+  serial_outb(COM1, c);
+}
+
+void com1_puts(char *s) {
+  while (*s) com1_putch(*s++);
+}
+
+void putchar_(char c) {
+  com1_putch(c);
+}
+