First pass at getting Acadia running under bochs.

- Create a bochs build script.
- Properly configure COM1

zion/debug/debug.cpp

@@ -39,3 +39,52 @@ void dbgln(const glcr::StringView& str) {
   dbg(str);
   dbg("\n");
 }
+
+namespace {
+
+// Helper function to write a byte to a specified COM1 register offset
+void write_serial_port(uint16_t offset, uint8_t value) {
+  outb(COM1 + offset, value);
+}
+
+// Helper function to read a byte from a specified COM1 register offset
+uint8_t read_serial_port(uint16_t offset) { return inb(COM1 + offset); }
+
+}  // namespace
+
+namespace serial {
+
+// Function to initialize the serial port with a given baud rate
+void initialize(uint32_t baud_rate) {
+  // Disable interrupts
+  write_serial_port(1, 0x00);
+
+  // Enable DLAB (Divisor Latch Access Bit) in Line Control Register (LCR)
+  write_serial_port(3, read_serial_port(3) | 0x80);
+
+  // Calculate the divisor
+  // Baud rate = 115200 / divisor (approximately)
+  uint16_t divisor = 115200 / baud_rate;
+
+  // Set the low byte of the divisor
+  write_serial_port(0, divisor & 0xFF);
+
+  // Set the high byte of the divisor
+  write_serial_port(1, (divisor >> 8) & 0xFF);
+
+  // Clear DLAB and set data bits, stop bits, and parity
+  // 8 data bits, 1 stop bit, no parity
+  write_serial_port(3, 0x03);  // 00000011b
+
+  // Enable FIFO, clear buffers, set trigger level (e.g., 1 byte)
+  write_serial_port(2, 0xC7);  // 11000111b
+
+  // Enable IRQs (optional, for interrupt-driven communication)
+  // write_serial_port(1, 0x01);
+
+  // Set Modem Control Register (MCR)
+  // Enable RTS, DTR, OUT1, OUT2, loopback off, IRQs enabled
+  write_serial_port(4, 0x0B);  // 00001011b
+}
+
+}  // namespace serial

zion/debug/debug.h

@@ -37,3 +37,9 @@ void panic(const char* str, Args&&... args) {
 #define UNREACHABLE                                                  \
   panic("Unreachable {}, {}", glcr::StringView(__FILE__), __LINE__); \
   __builtin_unreachable();
+
+namespace serial {
+
+void initialize(uint32_t baud_rate);
+
+}