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#include "print.h"
#include <stdint.h>
#include <sys.h>
#include <time.h>
#define CMOS_WRITE_PORT 0x70
#define CMOS_READ_PORT 0x71
#define CMOS_REG_SEC 0x00
#define CMOS_REG_MIN 0x02
#define CMOS_REG_HOUR 0x04
#define CMOS_REG_WDAY 0x06
#define CMOS_REG_MDAY 0x07
#define CMOS_REG_MON 0x08
#define CMOS_REG_YEAR 0x09
#define CMOS_REG_CEN 0x32
static struct Time time;
static struct Time localtime;
static int cur_offset = 0;
static uint8_t cmos_read(uint8_t reg) {
uint8_t hex, ret;
outb(CMOS_WRITE_PORT, reg);
hex = inb(CMOS_READ_PORT);
ret = hex & 0x0F;
ret += (hex & 0xF0) / 16 * 10;
return ret;
}
static int mday_offset[12] = {
0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334
};
static int month_days[12] = {
31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
};
static void update_localtime(void) {
int change, max;
// set localtime
localtime = time;
// do we acutally need to do anything
if (cur_offset == 0) return;
localtime.hour += cur_offset;
// check if day rolled over
change = localtime.hour < 0 ? -1 : localtime.hour >= 24 ? 1 : 0;
if (!change) return;
// roll over day
localtime.hour = (localtime.hour + 24) % 24;
localtime.wday = (localtime.wday + change + 7) % 7;
localtime.mday += change;
localtime.yday += change;
// check if month rolled over
max = month_days[localtime.mon];
if (localtime.leap && localtime.mon == 1) max++;
change = localtime.mday < 0 ? -1 : localtime.mday >= max ? 1 : 0;
if (!change) return;
// roll over month
localtime.mon = (localtime.mon + change + 12) % 12;
// check if year rolled over
max = localtime.leap ? 366 : 365;
change = localtime.yday < 0 ? -1 : localtime.yday >= max ? 1 : 0;
if (!change) return;
// roll over year
localtime.yn += change;
// check if cen rolled over
change = localtime.yn < 0 ? -1 : localtime.yn >= 100 ? 1 : 0;
if (!change) goto year;
// roll over cen
localtime.cen += change;
year:
localtime.year = localtime.yn + localtime.cen * 100;
localtime.leap = localtime.year % 4 == 0 && localtime.year % 100 != 0;
if (localtime.leap && localtime.yday == -1)
localtime.yday = 365;
else if (localtime.yday == -1)
localtime.yday = 364;
else
localtime.yday = 0;
localtime.year -= 1900;
}
void rtc_set_timezone(int offset) {
cur_offset = offset;
}
void rtc_update(void) {
time.sec = cmos_read(CMOS_REG_SEC);
time.min = cmos_read(CMOS_REG_MIN);
time.hour = cmos_read(CMOS_REG_HOUR);
time.wday = cmos_read(CMOS_REG_WDAY) - 1;
time.mday = cmos_read(CMOS_REG_MDAY);
time.mon = cmos_read(CMOS_REG_MON) - 1;
time.yn = cmos_read(CMOS_REG_YEAR);
time.cen = 20;
time.year = time.yn + time.cen * 100;
time.leap = time.year % 4 == 0 && time.year % 100 != 0;
time.yday = mday_offset[time.mon] + time.mday;
if (time.leap && time.mon > 2)
time.yday++;
time.year -= 1900;
update_localtime();
}
struct Time *rtc_utctime(void) {
return &time;
}
struct Time *rtc_localtime(void) {
return &localtime;
}
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