-- IntervalTimerHeadDorado.mesa
-- Last Edited by: Taft, March 31, 1983 9:12 am
-- Last Edited by: Stewart, January 1, 1984 6:24 pm

DIRECTORY
  Basics USING [LowHalf],
  DeviceCleanup USING [Await, Item, Reason],
  DoradoInputOutput USING [SetIntervalTimer],
  IntervalTimerFace,
  Loader USING [ MakeProcedureResident, MakeGlobalFrameResident ],
  PrincOpsUtils USING [AllocateNakedCondition, LongNotify],
  ProcessorFace USING [GetClockPulses];

IntervalTimerHeadDorado: MONITOR
  IMPORTS Basics, DeviceCleanup, DoradoInputOutput, Loader, PrincOpsUtils, ProcessorFace
  EXPORTS IntervalTimerFace =
  BEGIN OPEN IntervalTimerFace;

  csb: LONG POINTER TO IntervalTimerCSB = LOOPHOLE[LONG[177422B]];
  IntervalTimerCSB: TYPE = RECORD [
    wakeups: WORD];

  nakedCondition: LONG POINTER TO CONDITION;

  expirationTime: ClockPulses;

  SetExpirationTime: PUBLIC PROCEDURE [time: ClockPulses] =
    BEGIN
    expirationTime _ time;
    DoradoInputOutput.SetIntervalTimer[Basics.LowHalf[expirationTime]];
    IF LOOPHOLE[ProcessorFace.GetClockPulses[] - expirationTime, INT] >= 0 THEN
      PrincOpsUtils.LongNotify[nakedCondition];
    END;

  Wait: PUBLIC ENTRY PROCEDURE =
    BEGIN
    DO
      WAIT nakedCondition;
      IF LOOPHOLE[ProcessorFace.GetClockPulses[] - expirationTime, INT] >= 0 THEN EXIT;
      SetExpirationTime[expirationTime];
      ENDLOOP;
    END;

  exists: PUBLIC BOOLEAN _ TRUE;

  InitializeCleanup: PROCEDURE =
    BEGIN
    item: DeviceCleanup.Item;
    reason: DeviceCleanup.Reason;
    savedCSB: IntervalTimerCSB;
    DO
      reason _ DeviceCleanup.Await[@item];
      SELECT reason FROM
    turnOff, kill =>
      BEGIN
      savedCSB _ csb^;
      csb.wakeups _ 0;
      END;
    turnOn =>
      BEGIN
      csb^ _ savedCSB;
      SetExpirationTime[expirationTime];
      END;
    ENDCASE
      ENDLOOP
    END;

  Start: PROCEDURE =
    BEGIN
    [cv: nakedCondition, mask: csb.wakeups] _ PrincOpsUtils.AllocateNakedCondition[];
    Loader.MakeProcedureResident[InitializeCleanup];
    Loader.MakeGlobalFrameResident[InitializeCleanup];
    InitializeCleanup[];
    -- RemainingHeads.Start[];
    END;

  Start[];
  END.
January 1, 1984 6:24 pm, Stewart, added Loader procedures on advice of Taft