45 lines
1.4 KiB
C
45 lines
1.4 KiB
C
|
#include <stddef.h>
|
||
|
|
#include <stdint.h>
|
||
|
|
#include <lib/time.h>
|
||
|
|
#include <lib/real.h>
|
||
|
|
#include <lib/blib.h>
|
||
|
|
|
||
|
|
// Julian date calculation from https://en.wikipedia.org/wiki/Julian_day
|
||
|
|
static uint64_t get_jdn(uint8_t days, uint8_t months, uint16_t years) {
|
||
|
|
return (1461 * (years + 4800 + (months - 14)/12))/4 + (367 *
|
||
|
|
(months - 2 - 12 * ((months - 14)/12)))/12 -
|
||
|
|
(3 * ((years + 4900 + (months - 14)/12)/100))/4
|
||
|
|
+ days - 32075;
|
||
|
|
}
|
||
|
|
|
||
|
|
static uint64_t get_unix_epoch(uint8_t seconds, uint8_t minutes, uint8_t hours,
|
||
|
|
uint8_t days, uint8_t months, uint16_t years) {
|
||
|
|
uint64_t jdn_current = get_jdn(days, months, years);
|
||
|
|
uint64_t jdn_1970 = get_jdn(1, 1, 1970);
|
||
|
|
|
||
|
|
uint64_t jdn_diff = jdn_current - jdn_1970;
|
||
|
|
|
||
|
|
return (jdn_diff * (60 * 60 * 24)) + hours * 3600 + minutes * 60 + seconds;
|
||
|
|
}
|
||
|
|
|
||
|
|
uint64_t time(void) {
|
||
|
|
struct rm_regs r = {0};
|
||
|
|
|
||
|
|
r.eax = 0x0400;
|
||
|
|
rm_int(0x1a, &r, &r);
|
||
|
|
|
||
|
|
uint8_t day = bcd_to_int( r.edx & 0x00ff);
|
||
|
|
uint8_t month = bcd_to_int((r.edx & 0xff00) >> 8);
|
||
|
|
uint16_t year = bcd_to_int( r.ecx & 0x00ff) +
|
||
|
|
/* century */ bcd_to_int((r.ecx & 0xff00) >> 8) * 100;
|
||
|
|
|
||
|
|
r.eax = 0x0200;
|
||
|
|
rm_int(0x1a, &r, &r);
|
||
|
|
|
||
|
|
uint8_t second = bcd_to_int((r.edx & 0xff00) >> 8);
|
||
|
|
uint8_t minute = bcd_to_int( r.ecx & 0x00ff);
|
||
|
|
uint8_t hour = bcd_to_int((r.ecx & 0xff00) >> 8);
|
||
|
|
|
||
|
|
return get_unix_epoch(second, minute, hour, day, month, year);
|
||
|
|
}
|