-- File: TedIn.mesa, Last Edit: HGM  February 24, 1980  5:34 AM

-- Copyright  Xerox Corporation 1979, 1980

DIRECTORY
  CommUtilDefs: FROM "CommUtilDefs" USING [GetTicks, msPerTick],
  TedDefs: FROM "TedDefs",
  AltoEthernetDefs: FROM "AltoEthernetDefs",
  BufferDefs: FROM "BufferDefs",
  DriverTypes: FROM "DriverTypes" USING [pupEthernetPacket];

TedIn: MONITOR LOCKS TedDefs.lock
  IMPORTS CommUtilDefs, AltoEthernetDefs, TedDefs
  EXPORTS TedDefs
  SHARES BufferDefs, DriverTypes =
BEGIN OPEN BufferDefs, AltoEthernetDefs, TedDefs;

Watcher: PUBLIC PROCEDURE =
  BEGIN
  UNTIL tedPleaseStop DO
    THROUGH [0..25) DO
      IF myDevice.postData=EthernetNotPosted THEN EXIT;
-- If the post location is not zero, an interrupt should be pending.  Since the interrupt routine is higher priority than we are, it should get processed before we can see it.  If we get here, an interrupt has probably been lost.  It could have been generated between the time we started decoding the instruction and the time that the data is actually fetched.  That is why we look at the post location several times.  Of course, if it is still not zero when we look again, it could be a new interrupt that has just arrived.
      REPEAT FINISHED =>
        BEGIN
        WatcherNotify[];
        END;
      ENDLOOP;
    IF currentOutputBuffer#NIL
    AND (CommUtilDefs.GetTicks[]-timeSendStarted)>250/CommUtilDefs.msPerTick THEN
      StartIO[resetCommand];  -- interrupt code will flush it
    WatcherWait[];
    ENDLOOP;
  END;

WatcherWait: ENTRY PROCEDURE = INLINE
  BEGIN
  WAIT timer;
  END;

WatcherNotify: ENTRY PROCEDURE = INLINE
  BEGIN
  NOTIFY hardware;
  END;

DecapsulateBuffer: PUBLIC PROCEDURE [b: Buffer] RETURNS [BufferType] =
  BEGIN
  SELECT b.encapsulation.ethernetType FROM
    DriverTypes.pupEthernetPacket =>
      BEGIN
      IF b.length#((b.pupLength+1+ethernetEncapsulationBytes)/2) THEN 
        BEGIN
        RETURN[rejected];
        END;
      RETURN[pup];
      END;
    ENDCASE => RETURN[rejected];
  END;

END.  -- TedIn(2048)\495b7B133i525I307b11B57b13B62b17B