console vga stuff

kernel/drivers/serial/serial.c

@@ -0,0 +1,37 @@
+#include <drivers/serial/serial.h>
+#include <common.h>
+
+#define COM1 0x3F8
+
+int is_transmit_empty() {
+    return inb(COM1 + 5) & 0x20;
+}
+
+void write_serial(char a) {
+    while (is_transmit_empty() == 0);
+    outb(COM1, a);
+}
+
+void print_serial(const char* str) {
+    for (int i = 0; str[i] != '\0'; i++) {
+        write_serial(str[i]);
+    }
+}
+
+void print_serial_hex(uint32_t val) {
+    char hex_chars[] = "0123456789ABCDEF";
+    print_serial("0x");
+    for (int i = 28; i >= 0; i -= 4) {
+        write_serial(hex_chars[(val >> i) & 0x0F]);
+    }
+}
+
+void init_serial() {
+  outb(COM1 + 1, 0x00);    // Disable all interrupts
+  outb(COM1 + 3, 0x80);    // Enable DLAB (set baud rate divisor)
+  outb(COM1 + 0, 0x01);    // Set divisor to 1 (lo byte) -> 115200 baud
+  outb(COM1 + 1, 0x00);    //                  (hi byte)
+  outb(COM1 + 3, 0x03);    // 8 bits, no parity, one stop bit
+  outb(COM1 + 2, 0xC7);    // Enable FIFO, clear them, with 14-byte threshold
+  outb(COM1 + 4, 0x0B);    // IRQs enabled, RTS/DSR set
+}

kernel/drivers/serial/serial.h

@@ -0,0 +1,12 @@
+#ifndef D_SERIAL_H
+#define D_SERIAL_H
+
+#include <stdint.h>
+
+void init_serial();
+void print_serial_hex(uint32_t val);
+void print_serial(const char* str);
+void write_serial(char a);
+int is_transmit_empty();
+
+#endif