1 files changed, 137 insertions, 0 deletions
diff --git a/src/Dolphin/os/OSTime.c b/src/Dolphin/os/OSTime.c
new file mode 100644
index 0000000..4250798
--- /dev/null
+++ b/src/Dolphin/os/OSTime.c
@@ -0,0 +1,137 @@
+#include <dolphin/os.h>
+
+#define OS_TIME_MONTH_MAX 12
+#define OS_TIME_WEEK_DAY_MAX 7
+#define OS_TIME_YEAR_DAY_MAX 365
+
+// End of each month in standard year
+static s32 YearDays[OS_TIME_MONTH_MAX] = {0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334};
+// End of each month in leap year
+static s32 LeapYearDays[OS_TIME_MONTH_MAX] = {0,   31,  60,  91,  121, 152,
+                                              182, 213, 244, 274, 305, 335};
+
+asm OSTime OSGetTime(void) {
+  // clang-format off
+    nofralloc
+
+    mftbu r3
+    mftb r4
+
+    // Check for possible carry from TBL to TBU
+    mftbu r5
+    cmpw r3, r5
+    bne OSGetTime
+
+    blr
+  // clang-format on
+}
+
+asm OSTick OSGetTick(void){
+    // clang-format off
+    nofralloc
+
+    mftb r3
+    blr
+    // clang-format on
+}
+
+#define OS_SYSTEMTIME_BASE 0x30D8
+
+OSTime __OSGetSystemTime(void) {
+  BOOL enabled;
+  OSTime* timeAdjustAddr = (OSTime*)(OS_BASE_CACHED + OS_SYSTEMTIME_BASE);
+  OSTime result;
+
+  enabled = OSDisableInterrupts();
+  result = *timeAdjustAddr + OSGetTime();
+  OSRestoreInterrupts(enabled);
+
+  return result;
+}
+
+OSTime __OSTimeToSystemTime(OSTime time) {
+  BOOL enabled;
+  OSTime* timeAdjustAddr = (OSTime*)(OS_BASE_CACHED + OS_SYSTEMTIME_BASE);
+  OSTime result;
+
+  enabled = OSDisableInterrupts();
+  result = *timeAdjustAddr + time;
+  OSRestoreInterrupts(enabled);
+
+  return result;
+}
+
+static BOOL IsLeapYear(s32 year) { return (year % 4 == 0 && year % 100 != 0) || (year % 400 == 0); }
+
+static s32 GetYearDays(s32 year, s32 mon) {
+  return (IsLeapYear(year) ? LeapYearDays : YearDays)[mon];
+}
+
+static s32 GetLeapDays(s32 year) {
+  if (year < 1) {
+    return 0;
+  }
+  return (year + 3) / 4 - (year - 1) / 100 + (year - 1) / 400;
+}
+
+static void GetDates(s32 days, OSCalendarTime* cal) {
+  s32 year;
+  s32 totalDays;
+  s32* p_days;
+  s32 month;
+  cal->wday = (days + 6) % OS_TIME_WEEK_DAY_MAX;
+
+  for (year = days / OS_TIME_YEAR_DAY_MAX;
+       days < (totalDays = year * OS_TIME_YEAR_DAY_MAX + GetLeapDays(year));) {
+    year--;
+  }
+
+  days -= totalDays;
+  cal->year = year;
+  cal->yday = days;
+
+  p_days = IsLeapYear(year) ? LeapYearDays : YearDays;
+  month = OS_TIME_MONTH_MAX;
+  while (days < p_days[--month]) {
+    ;
+  }
+  cal->mon = month;
+  cal->mday = days - p_days[month] + 1;
+}
+
+#define BIAS (2000 * 365 + (2000 + 3) / 4 - (2000 - 1) / 100 + (2000 - 1) / 400)
+
+#pragma push
+#pragma dont_inline on
+void OSTicksToCalendarTime(OSTime ticks, OSCalendarTime* td) {
+  int days;
+  int secs;
+  OSTime d;
+
+  d = ticks % OSSecondsToTicks(1);
+  if (d < 0) {
+    d += OSSecondsToTicks(1);
+  }
+  td->usec = (int)(OSTicksToMicroseconds(d) % 1000);
+  td->msec = (int)(OSTicksToMilliseconds(d) % 1000);
+
+  ticks -= d;
+  days = (int)(OSTicksToSeconds(ticks) / 86400 + BIAS);
+  secs = (int)(OSTicksToSeconds(ticks) % 86400);
+  if (secs < 0) {
+    days -= 1;
+    secs += 24 * 60 * 60;
+  }
+
+  GetDates(days, td);
+
+  td->hour = secs / 60 / 60;
+  td->min = (secs / 60) % 60;
+  td->sec = secs % 60;
+}
+#pragma dont_inline reset
+
+OSTime OSCalendarTimeToTicks(OSCalendarTime* time) {
+  ;
+  ;
+}