1637 

  1638 findExceptional

  1639     "walk along the sender chain (starting with the sender), 

  1640      for a context which is marked as handle or raise context.

  1641      This non-standard interface is only to be used by exception"

  1642 

  1643     "/ this could have been (actually: was) implemented as:

  1644     "/

  1645     "/  |con|

  1646     "/

  1647     "/  con := self.

  1648     "/  [con notNil] whileTrue:[

  1649     "/      [con isHandleContext] ifTrue:[^con].

  1650     "/      [con isRaiseContext] ifTrue:[^con].

  1651     "/      con := con sender.

  1652     "/  ].

  1653     "/  ^ nil

  1654     "/

  1655     "/ and the code below does exactly this (somewhat faster, though).

  1656     "/

  1657     "/ (it avoids referencing all intermediate contexts, which would mark them special,

  1658     "/  although they aren't really - this is expert knowledge, no need to understand that ...)

  1659 

  1660 %{  /* NOCONTEXT */

  1661 

  1662     OBJ theContext;

  1663 

  1664     theContext = self;

  1665     while (__isNonNilObject(theContext)) {

  1666         if ((INT)(__ContextInstPtr(theContext)->c_flags) & __MASKSMALLINT(__HANDLE_MARK|__RAISE_MARK)) {

  1667             if (__isLazy(theContext)) {

  1668                 __PATCHUPCONTEXT(theContext);

  1669             }

  1670 

  1671             if (! __isNonLIFO(theContext)) {

  1672                 /* 

  1673                  * to be prepared for the worst situation 

  1674                  * (the sender is not stored, so the trap won't catch it)

  1675                  * make the writeBarrier trigger manually.

  1676                  * We'll see, if this is really required.

  1677                  */

  1678                 theContext->o_space |= CATCHMARK;

  1679 #if 0

  1680                 _markNonLIFO(theContext);

  1681 #endif

  1682             }

  1683             RETURN (theContext);

  1684         }

  1685         theContext = __ContextInstPtr(theContext)->c_sender;

  1686     }

  1687 %}.

  1688     ^ nil

  1689 !