/***** cmos.c ********************************************************
 * (c) 2010 CTA Systems Inc. All rights reserved. Glory To God       *
 *                                                                   *
 *          CMOS I/O Routines                                        *
 *          =================                                        *
 *                                                                   *
 * ! IMPORTANT NOTE !  Close interrupts before any CMOS operation    *
 ************************************************************ cta os */

#include <system.h>
#include <time.h>
#include "cmos.h"

/*****************************************************************
 *    !!!!!!!!!!          IMPORTANT NOTE          !!!!!!!!!!     *
 *    You should close interrupts before any CMOS operation.     *
 *****************************************************************/
inline unsigned char i86_cmos_read (unsigned char address)
{
      outportb(0x70, address); iowait();
      return inportb(0x71);
}

inline void i86_cmos_write (unsigned char address, unsigned char val)
{
      outportb(0x70, address); iowait();
      outportb(0x71, val);
}

void i86_cmos_write_clock (const TIME* time)
{
      unsigned char BCD = ((i86_cmos_read(0x0b)&4)==0) ? 1 : 0;
      unsigned char ampm = ((i86_cmos_read(0x0b)&2)==0) ? 1 : 0;
      
      i86_cmos_write (0, (BCD) ? (time->second%10) | (time->second/10*16) : time->second);        // Seconds
      i86_cmos_write (2, (BCD) ? (time->minute%10) | (time->minute/10*16) : time->minute);        // Minutes

      if (ampm && time->hour > 12)                                                                // Hours
            i86_cmos_write (4, (BCD) ? (((time->hour - 12) % 10) | ((time->hour - 12)/10*16) | 0x80) : (time->hour | 0x80) );
      
      else if (ampm && time->hour == 0)                                                           // Midnight convention: 12 PM = 00:00
            i86_cmos_write (4, (BCD) ? 0x92 : 0x8C); 
      
      else i86_cmos_write (4, (BCD) ? (time->hour%10) | (time->hour/10*16) : time->hour);         // 24h / AM

      i86_cmos_write (6, (BCD) ? (time->weekday%10) | (time->weekday/10*16) : time->weekday);     // Weekday
      i86_cmos_write (7, (BCD) ? (time->day%10) | (time->day/10*16) : time->day);                 // Day
      i86_cmos_write (8, (BCD) ? (time->month%10) | (time->month/10*16) : time->month);           // Month
      i86_cmos_write (9, (BCD) ? (time->year%10) | (time->year/10*16) : time->year);              // Year
      i86_cmos_write (0x32, (BCD) ? (time->century%10) | (time->century/10*16) : time->century);  // Century
}

void i86_cmos_read_clock(TIME* tim)
{
      unsigned char BCD = ((i86_cmos_read(0x0b)&4)==0) ? 1 : 0;
      unsigned char am_pm = ((i86_cmos_read(0x0b)&2)==0) ? 1 : 0;
      
      tim->second = (BCD) ? (i86_cmos_read(0x00)%16) + 10*(i86_cmos_read(0x00)/16): i86_cmos_read(0x00);
      tim->minute = (BCD) ? (i86_cmos_read(0x02)%16) + 10*(i86_cmos_read(0x02)/16): i86_cmos_read(0x02);

      // Time is PM
      if (am_pm && i86_cmos_read(0x04)&80) {
            tim->hour = (BCD) ? ((i86_cmos_read(0x04)-0x80)%16) + 10*((i86_cmos_read(0x04)-0x80)/16): i86_cmos_read(0x04)-0x80;
            tim->hour += 12;
      }
      // 24Hour format, or AM
      else tim->hour = (BCD) ? (i86_cmos_read(0x04)%16) + 10*(i86_cmos_read(0x04)/16): i86_cmos_read(0x04);     

      tim->weekday = (BCD) ? (i86_cmos_read(0x06)%16) + 10*(i86_cmos_read(0x06)/16): i86_cmos_read(0x06);
      tim->day = (BCD) ? (i86_cmos_read(0x07)%16) + 10*(i86_cmos_read(0x07)/16): i86_cmos_read(0x07);
      tim->month = (BCD) ? (i86_cmos_read(0x08)%16) + 10*(i86_cmos_read(0x08)/16): i86_cmos_read(0x08);
      tim->year = (BCD) ? (i86_cmos_read(0x09)%16) + 10*(i86_cmos_read(0x09)/16): i86_cmos_read(0x09);
      tim->century = (BCD) ? (i86_cmos_read(0x32)%16) + 10*(i86_cmos_read(0x32)/16): i86_cmos_read(0x32);
}


unsigned char i86_cmos_read_floppy_drives ()
{
      outportb (0x70, 0x10);
      return inportb(0x71);
}