1 files changed, 183 insertions, 0 deletions
diff --git a/src/Dolphin/os/OSAlarm.c b/src/Dolphin/os/OSAlarm.c
new file mode 100644
index 0000000..d362ceb
--- /dev/null
+++ b/src/Dolphin/os/OSAlarm.c
@@ -0,0 +1,183 @@
+#include "dolphin/PPCArch.h"
+#include "dolphin/os/OSPriv.h"
+
+static struct OSAlarmQueue {
+  OSAlarm* head;
+  OSAlarm* tail;
+} AlarmQueue;
+
+static void DecrementerExceptionHandler(__OSException exception, OSContext* context);
+static BOOL OnReset(BOOL final);
+
+void OSInitAlarm(void) {
+  if (__OSGetExceptionHandler(8) != DecrementerExceptionHandler) {
+    AlarmQueue.head = AlarmQueue.tail = NULL;
+    __OSSetExceptionHandler(8, DecrementerExceptionHandler);
+  }
+}
+
+void OSCreateAlarm(OSAlarm* alarm) {
+  alarm->handler = 0;
+  alarm->tag = 0;
+}
+
+static void SetTimer(OSAlarm* alarm) {
+  OSTime delta;
+
+  delta = alarm->fire - __OSGetSystemTime();
+  if (delta < 0) {
+    PPCMtdec(0);
+  } else if (delta < 0x80000000) {
+    PPCMtdec((u32)delta);
+  } else {
+    PPCMtdec(0x7fffffff);
+  }
+}
+
+static void InsertAlarm(OSAlarm* alarm, OSTime fire, OSAlarmHandler handler) {
+  OSAlarm* next;
+  OSAlarm* prev;
+
+  if (0 < alarm->period) {
+    OSTime time = __OSGetSystemTime();
+
+    fire = alarm->start;
+    if (alarm->start < time) {
+      fire += alarm->period * ((time - alarm->start) / alarm->period + 1);
+    }
+  }
+
+  alarm->handler = handler;
+  alarm->fire = fire;
+
+  for (next = AlarmQueue.head; next; next = next->next) {
+    if (next->fire <= fire) {
+      continue;
+    }
+
+    alarm->prev = next->prev;
+    next->prev = alarm;
+    alarm->next = next;
+    prev = alarm->prev;
+    if (prev) {
+      prev->next = alarm;
+    } else {
+      AlarmQueue.head = alarm;
+      SetTimer(alarm);
+    }
+    return;
+  }
+  alarm->next = 0;
+  prev = AlarmQueue.tail;
+  AlarmQueue.tail = alarm;
+  alarm->prev = prev;
+  if (prev) {
+    prev->next = alarm;
+  } else {
+    AlarmQueue.head = AlarmQueue.tail = alarm;
+    SetTimer(alarm);
+  }
+}
+
+void OSSetAlarm(OSAlarm* alarm, OSTime tick, OSAlarmHandler handler) {
+  BOOL enabled;
+  enabled = OSDisableInterrupts();
+  alarm->period = 0;
+  InsertAlarm(alarm, __OSGetSystemTime() + tick, handler);
+  OSRestoreInterrupts(enabled);
+}
+
+void OSSetPeriodicAlarm(OSAlarm* alarm, OSTime start, OSTime period, OSAlarmHandler handler) {
+  BOOL enabled;
+  enabled = OSDisableInterrupts();
+  alarm->period = period;
+  alarm->start = __OSTimeToSystemTime(start);
+  InsertAlarm(alarm, 0, handler);
+  OSRestoreInterrupts(enabled);
+}
+
+void OSCancelAlarm(OSAlarm* alarm) {
+  OSAlarm* next;
+  BOOL enabled;
+
+  enabled = OSDisableInterrupts();
+
+  if (alarm->handler == 0) {
+    OSRestoreInterrupts(enabled);
+    return;
+  }
+
+  next = alarm->next;
+  if (next == 0) {
+    AlarmQueue.tail = alarm->prev;
+  } else {
+    next->prev = alarm->prev;
+  }
+  if (alarm->prev) {
+    alarm->prev->next = next;
+  } else {
+    AlarmQueue.head = next;
+    if (next) {
+      SetTimer(next);
+    }
+  }
+  alarm->handler = 0;
+
+  OSRestoreInterrupts(enabled);
+}
+
+static void DecrementerExceptionCallback(register __OSException exception,
+                                         register OSContext* context) {
+  OSAlarm* alarm;
+  OSAlarm* next;
+  OSAlarmHandler handler;
+  OSTime time;
+  OSContext exceptionContext;
+  time = __OSGetSystemTime();
+  alarm = AlarmQueue.head;
+  if (alarm == 0) {
+    OSLoadContext(context);
+  }
+
+  if (time < alarm->fire) {
+    SetTimer(alarm);
+    OSLoadContext(context);
+  }
+
+  next = alarm->next;
+  AlarmQueue.head = next;
+  if (next == 0) {
+    AlarmQueue.tail = 0;
+  } else {
+    next->prev = 0;
+  }
+
+  handler = alarm->handler;
+  alarm->handler = 0;
+  if (0 < alarm->period) {
+    InsertAlarm(alarm, 0, handler);
+  }
+
+  if (AlarmQueue.head) {
+    SetTimer(AlarmQueue.head);
+  }
+
+  OSDisableScheduler();
+  OSClearContext(&exceptionContext);
+  OSSetCurrentContext(&exceptionContext);
+  handler(alarm, context);
+  OSClearContext(&exceptionContext);
+  OSSetCurrentContext(context);
+  OSEnableScheduler();
+  __OSReschedule();
+  OSLoadContext(context);
+}
+
+static asm void DecrementerExceptionHandler(register __OSException exception,
+                                            register OSContext* context) {
+
+  nofralloc 
+  OS_EXCEPTION_SAVE_GPRS(context)
+  stwu r1, -8(r1)
+  b DecrementerExceptionCallback
+}