First pass at getting Acadia running under bochs.

- Create a bochs build script.
- Properly configure COM1
This commit is contained in:
Drew Galbraith 2025-05-06 22:22:02 -07:00
parent 93d1299bd9
commit 5a20c23569
9 changed files with 153 additions and 40 deletions

View file

@ -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