#include <stdint.h>
#include <stdbool.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
};

bool error;
#define SERIAL_SPIN_LIMIT 65535

bool serr() {
  return error;
}

void init_serial() {
  error = false;
  outb(CP_1 | CP_INT, 0);
  outb(CP_1 | CP_LINE, CL_BAUD);
  outb(CP_1 | CP_DIVLOW, 0x03);//38400
  outb(CP_1 | CP_DIVHIGH, 0x00);//baud
  outb(CP_1 | CP_LINE, CL_8BIT);
  outb(CP_1 | CP_FIFO, 0xc7);//?
}

void sout(char b) {
  if (error)
    return;
  uint16_t s = SERIAL_SPIN_LIMIT;
  while (!(inb(CP_1 | CP_LINE_S) & CLS_WRITE))
    if (!--s) {
      error = true;
      return;
    }
  outb(CP_1 | CP_DATA, (uint8_t)b);
}

void soutsz(char *s) {
  while (*s)
    sout(*(s++));
}

void soutsn(char *s, uint8_t n) {
  while (n--)
    sout(*(s++));
}

char sin() {
  if (error)
    return 0;
  while (!(inb(CP_1 | CP_LINE_S) & CLS_READ))
    ;//spin
  return (char)inb(CP_1 | CP_DATA);
}

void sinsn(char *s, uint8_t n) {
  while (n--)
    *(s++) = sin();
}