#pragma once

enum uart_16550_offset {
  Data = 0, // read from receive buffer / write to transmit buffer | BaudDiv_l
  InterruptControl = 1, // interrupt enable | BaudDiv_h
  FifoControl = 2,      // interrupt ID and FIFO control
  LineControl = 3,      // most significant bit is the DLAB
  ModemControl = 4,
  LineStatus = 5,
  ModemStatus = 6,
  Scratch = 7,
};
// Line Control
// | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
// |dla|   | parity    | s | data  |

enum LineControl {
  d5bit = 0b00000000, // data bits
  d6bit = 0b00000001,
  d7bit = 0b00000010,
  d8bit = 0b00000011,
  // none = 0b00000000, // parity bits
  odd = 0b00001000,
  even = 0b00011000,
  mark = 0b00101000,
  space = 0b00111000,
  // s1bit = 0b00000000, // stop bits
  s2bit = 0b00000100, // 1.5 for 5bit data; 2 otherwise
  dlab = 0b10000000,  // divisor latch access bit
};

// Line Status Register
enum LineStatus {
  DR = 0b00000001,   // data ready: see if there is data to read
  OE = 0b00000010,   // overrun error: see if there has been data lost
  PE = 0b00000100,   // parity error: see if there was error in transmission
  FE = 0b00001000,   // framing error: see if a stop bit was missing
  BI = 0b00010000,   // break indicator: see if there is a break in data input
  THRE = 0b00100000, // transmitter holding register empty: see if transmission buffer is empty
  TEMT = 0b01000000, // transmitter empty: see if transmitter is not doing anything
  ERRO = 0b10000000, // impending error: see if there is an error with a word in the input buffer
};

enum UART {
  COM1 = 0x3f8,
  COM2 = 0x2f8,
  COM3 = 0x3E8,
  COM4 = 0x2E8,
  COM5 = 0x5F8,
  COM6 = 0x4F8,
  COM7 = 0x5E8,
  COM8 = 0x4E8,
};

int uart_init(enum UART port);
void uart_write(enum UART port, char a);
int uart_puts(enum UART port, const char *string, int length);