* Sync up to trunk head (r65270).
[reactos.git] / boot / armllb / hw / time.c
1 /*
2 * PROJECT: ReactOS Boot Loader
3 * LICENSE: BSD - See COPYING.ARM in the top level directory
4 * FILE: boot/armllb/hw/time.c
5 * PURPOSE: LLB Time Routines
6 * PROGRAMMERS: ReactOS Portable Systems Group
7 */
8
9 #include "precomp.h"
10
11 #define LEAPS_THRU_END_OF(y) ((y)/4 - (y)/100 + (y)/400)
12
13 UCHAR LlbDaysInMonth[] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
14
15 #ifndef _ZOOM2_
16 TIMEINFO LlbTime;
17 #else
18 extern TIMEINFO LlbTime;
19 #endif
20
21 BOOLEAN
22 NTAPI
23 LlbIsLeapYear(IN ULONG Year)
24 {
25 /* Every 4, 100, or 400 years */
26 return (!(Year % 4) && (Year % 100)) || !(Year % 400);
27 }
28
29 ULONG
30 NTAPI
31 LlbDayOfMonth(IN ULONG Month,
32 IN ULONG Year)
33 {
34 /* Check how many days a month has, accounting for leap yearS */
35 return LlbDaysInMonth[Month] + (LlbIsLeapYear(Year) && Month == 1);
36 }
37
38 VOID
39 NTAPI
40 LlbConvertRtcTime(IN ULONG RtcTime,
41 OUT TIMEINFO* TimeInfo)
42 {
43 ULONG Month, Year, Days, DaysLeft;
44
45 /* Count the days, keep the minutes */
46 Days = RtcTime / 86400;
47 RtcTime -= Days * 86400;
48
49 /* Get the year, based on days since 1970 */
50 Year = 1970 + Days / 365;
51
52 /* Account for leap years which changed the number of days/year */
53 Days -= (Year - 1970) * 365 + LEAPS_THRU_END_OF(Year - 1) - LEAPS_THRU_END_OF(1970 - 1);
54 if (Days < 0)
55 {
56 /* We hit a leap year, so fixup the math */
57 Year--;
58 Days += 365 + LlbIsLeapYear(Year);
59 }
60
61 /* Count months */
62 for (Month = 0; Month < 11; Month++)
63 {
64 /* How many days in this month? */
65 DaysLeft = Days - LlbDayOfMonth(Month, Year);
66 if (DaysLeft < 0) break;
67
68 /* How many days left total? */
69 Days = DaysLeft;
70 }
71
72 /* Write the structure */
73 TimeInfo->Year = Year;
74 TimeInfo->Day = Days + 1;
75 TimeInfo->Month = Month + 1;
76 TimeInfo->Hour = RtcTime / 3600;
77 RtcTime -= TimeInfo->Hour * 3600;
78 TimeInfo->Minute = RtcTime / 60;
79 TimeInfo->Second = RtcTime - TimeInfo->Minute * 60;
80 }
81
82 TIMEINFO*
83 NTAPI
84 LlbGetTime(VOID)
85 {
86 ULONG RtcTime;
87
88 /* Read RTC time */
89 RtcTime = LlbHwRtcRead();
90 #ifndef _ZOOM2_
91 /* Convert it */
92 LlbConvertRtcTime(RtcTime, &LlbTime);
93 #endif
94 return &LlbTime;
95 }
96
97 /* EOF */