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#include "RTC.h"
#include "CMOS.h"
#include <AK/Assertions.h>
namespace RTC {
static time_t s_boot_time;
void initialize()
{
byte cmos_mode = CMOS::read(0x0b);
cmos_mode |= 2; // 24 hour mode
cmos_mode |= 4; // No BCD mode
CMOS::write(0x0b, cmos_mode);
s_boot_time = now();
}
time_t boot_time()
{
return s_boot_time;
}
static bool update_in_progress()
{
return CMOS::read(0x0a) & 0x80;
}
inline bool is_leap_year(unsigned year)
{
return ((year % 4 == 0) && ((year % 100 != 0) || (year % 400) == 0));
}
static unsigned days_in_months_since_start_of_year(unsigned month, unsigned year)
{
switch (month) {
case 11: return 30;
case 10: return 31;
case 9: return 30;
case 8: return 31;
case 7: return 31;
case 6: return 30;
case 5: return 31;
case 4: return 30;
case 3: return 31;
case 2:
if (is_leap_year(year))
return 29;
return 28;
case 1: return 31;
default: return 0;
}
}
static unsigned days_in_years_since_epoch(unsigned year)
{
unsigned days = 0;
while (year > 1969) {
days += 365;
if (is_leap_year(year))
++days;
--year;
}
return days;
}
void read_registers(unsigned& year, unsigned& month, unsigned& day, unsigned& hour, unsigned& minute, unsigned& second)
{
while (update_in_progress())
;
year = (CMOS::read(0x32) * 100) + CMOS::read(0x09);
month = CMOS::read(0x08);
day = CMOS::read(0x07);
hour = CMOS::read(0x04);
minute = CMOS::read(0x02);
second = CMOS::read(0x00);
}
time_t now()
{
// FIXME: We should probably do something more robust here.
// Perhaps read all the values twice and verify that they were identical.
// We don't want to be caught in the middle of an RTC register update.
while (update_in_progress())
;
unsigned year, month, day, hour, minute, second;
read_registers(year, month, day, hour, minute, second);
ASSERT(year >= 2018);
return days_in_years_since_epoch(year - 1) * 86400
+ days_in_months_since_start_of_year(month - 1, year) * 86400
+ (day - 1) * 86400
+ hour * 3600
+ minute * 60
+ second;
}
}
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