#include <stdbool.h>
#include <stdint.h>
#include "serial.h"
#include "util.h"

enum {
  CP_DATA    = 0x0,
  CP_INT     = 0x1,
  CP_FIFO    = 0x2,
  CP_LINE    = 0x3,
  CP_MODEM   = 0x4,
  CP_LINE_S  = 0x5,
  CP_MODEM_S = 0x6,

  CP_DIVLOW  = 0x0,
  CP_DIVHIGH = 0x1,

  CP_1 = 0x03f8,
  CP_2 = 0x02f8,
  CP_3 = 0x03e8,
  CP_4 = 0x02e8
};

enum {
  CL_BAUD  = 0x80,

  CL_PODD  = 0x08,
  CL_PEVEN = 0x0c,
  CL_PON   = 0x18,
  CL_POFF  = 0x1c,

  CL_LSTOP = 0x4,

  CL_5BIT  = 0x0,
  CL_6BIT  = 0x1,
  CL_7BIT  = 0x2,
  CL_8BIT  = 0x3
};

enum {
  CLS_B_ERR = 0x80,
  CLS_IDLE  = 0x40,
  CLS_WRITE = 0x20,
  CLS_BREAK = 0x10,
  CLS_FRAME = 0x08,
  CLS_PAR   = 0x04,
  CLS_OVER  = 0x02,
  CLS_READ  = 0x01
};

static const uint16_t ports[] = {
  CP_1, CP_2, CP_3, CP_4
};

static bool error[4];

void reset_error(enum serial_port n) {
  error[n] = false;
}

void init_serial() {
  for (enum serial_port i = COM1; i <= COM4; ++i) {
    error[i] = false;
    outb(ports[i] | CP_INT, 0);
    outb(ports[i] | CP_LINE, CL_BAUD);
    outb(ports[i] | CP_DIVLOW, 0x03);//38400
    outb(ports[i] | CP_DIVHIGH, 0x00);//baud
    outb(ports[i] | CP_LINE, CL_8BIT);
    outb(ports[i] | CP_FIFO, 0xc7);//?
  }
}

typedef uint16_t serial_spin_t;

void sout(enum serial_port n, uint8_t b) {
  if (error[n])
    return;
  serial_spin_t spinner = -1;
  while (!(inb(ports[n] | CP_LINE_S) & CLS_WRITE))
    if (--spinner) {
      error[n] = true;
      return;
    }
  outb(ports[n] | CP_DATA, b);
}

uint8_t sin(enum serial_port n) {
  if (error[n])
    return 0;
  while (!(inb(ports[n] | CP_LINE_S) & CLS_READ))
    ;//spin
  return inb(ports[n] | CP_DATA);
}