--- a/Context.st	Wed May 27 06:37:28 2015 +0200
+++ b/Context.st	Thu May 28 06:50:45 2015 +0200
@@ -824,10 +824,18 @@
      invalid until needed."
 
 %{  /* NOCONTEXT */
+#ifdef __SCHTEAM__
+    if (((STContinuation)self).caller == null) {
+	return __c__._RETURN_true();
+    }
+    return __c__._RETURN_false();
+    /* NOTREACHED */
+#else
     if ( __INST(sender_) == nil ) {
 	RETURN (true);
     }
     RETURN (false);
+#endif
 %}.
     ^ self sender isNil
 !
@@ -2030,7 +2038,9 @@
      and prevents a crash in such a case."
 
 %{
-#ifndef __SCHTEAM__
+#ifdef __SCHTEAM__
+    return __c__._RETURN( ((STContinuation)self).stSelf(__c__) );
+#else
     /*
      * special handling for (invalid) free objects.
      * these only appear if some primitiveCode does not correctly use SEND macros,
@@ -2055,7 +2065,7 @@
 
 %{  /* NOCONTEXT */
 #ifdef __SCHTEAM__
-    return context._RETURN (self.asSTContinuation().isMarkedForUnwind() ? STObject.True : STObject.False);
+    return context._RETURN ( ((STContinuation)self).isMarkedForUnwind() );
 #else
     RETURN ( ((INT)__INST(flags) & __MASKSMALLINT(__UNWIND_MARK)) ? true : false );
 #endif
@@ -2072,7 +2082,7 @@
 
 %{  /* NOCONTEXT */
 #ifdef __SCHTEAM__
-    self.asSTContinuation().markForHandle();
+    ((STContinuation)self).markForHandle();
 #else
      __INST(flags) = (OBJ)((INT)__INST(flags) | __MASKSMALLINT(__HANDLE_MARK));
 #endif
@@ -2088,7 +2098,7 @@
 
 %{  /* NOCONTEXT */
 #ifdef __SCHTEAM__
-    self.asSTContinuation().markForInterrupt();
+    ((STContinuation)self).markForInterrupt();
 #else
      __markInterrupted(__ContextInstPtr(self));
 #endif
@@ -2103,7 +2113,7 @@
 
 %{  /* NOCONTEXT */
 #ifdef __SCHTEAM__
-    self.asSTContinuation().markForInterruptOnUnwind();
+    ((STContinuation)self).markForInterruptOnUnwind();
 #else
      __INST(flags) = (OBJ)((INT)__INST(flags) | __MASKSMALLINT(__IRQ_ON_UNWIND));
 #endif
@@ -2117,7 +2127,7 @@
 
 %{  /* NOCONTEXT */
 #ifdef __SCHTEAM__
-    self.asSTContinuation().markForRaise();
+    ((STContinuation)self).markForRaise();
 #else
      __INST(flags) = (OBJ)((INT)__INST(flags) | __MASKSMALLINT(__RAISE_MARK));
 #endif
@@ -2133,7 +2143,7 @@
 
 %{  /* NOCONTEXT */
 #ifdef __SCHTEAM__
-    self.asSTContinuation().markForUnwind();
+    ((STContinuation)self).markForUnwind();
 #else
      __INST(flags) = (OBJ)((INT)__INST(flags) | __MASKSMALLINT(__UNWIND_MARK));
 #endif
@@ -2155,7 +2165,7 @@
 
 %{  /* NOCONTEXT */
 #ifdef __SCHTEAM__
-    ERROR("unimplemented");
+    ((STContinuation)self).caller = aContext.asSTContinuation();
 #else
     __INST(sender_) = aContext;
 #endif
@@ -2169,7 +2179,7 @@
 
 %{  /* NOCONTEXT */
 #ifdef __SCHTEAM__
-    self.asSTContinuation().unmarkForUnwind();
+    ((STContinuation)self).unmarkForUnwind();
 #else
     __INST(flags) = (OBJ)((INT)__INST(flags) & ~__MASKSMALLINT(__UNWIND_MARK));
 #endif
@@ -2203,13 +2213,16 @@
 %{  /* NOCONTEXT */
 #ifdef __SCHTEAM__
     {
-	STContinuation caller = self.sender();
+	STContinuation lastCallee = (STContinuation)self;
+	STContinuation caller = lastCallee.caller;
 
 	while (caller != null) {
 	    if (caller.isExceptionalSmalltalkContext()) {
+		caller = lastCallee.sender();   // exposed
 		return context._RETURN(caller);
 	    }
-	    caller = caller.sender();
+	    lastCallee = caller;
+	    caller = lastCallee.caller;
 	}
 	return context._RETURN( STObject.Nil );
     }
@@ -2269,7 +2282,9 @@
 %{  /* NOCONTEXT */
 #ifdef __SCHTEAM__
     {
-	STContinuation cont = self.sender();
+	STContinuation lastCallee = (STContinuation)self;
+	STContinuation cont = lastCallee.caller;
+
 	STObject sel1 = context.stArg(0);
 	STObject sel2 = context.stArg(1);
 	STObject sel3 = context.stArg(2);
@@ -2284,11 +2299,13 @@
 		    break;
 		}
 	    }
-	    cont = cont.sender();
+	    lastCallee = cont;
+	    cont = lastCallee.caller;
 	}
 	if (cont == null) {
 	    return __c__._RETURN_nil();
 	}
+	cont = lastCallee.sender();     // exposed
 	return __c__._RETURN(cont);
     }
     /* NOTREACHED */
@@ -2376,14 +2393,17 @@
 	    return __c__._RETURN(self);
 	}
 
-	STContinuation theContext = self.sender();
+	STContinuation lastCallee = (STContinuation)self;
+	STContinuation theContext = lastCallee.caller;
 
 	while (theContext != null) {
 	    if ((theContext == aContext)
 	     || theContext.isMarkedForUnwind()) {
+		theContext = lastCallee.sender();   // exposed
 		return __c__._RETURN(theContext);
 	    }
-	    theContext = theContext.sender();
+	    lastCallee = theContext;
+	    theContext = lastCallee.caller;
 	}
     }
 #else
@@ -2446,19 +2466,24 @@
 %{  /* NOCONTEXT */
 #ifdef __SCHTEAM__
     {
-	STContinuation theContext = self.sender();
+	STContinuation lastCallee = (STContinuation)self;
+	STContinuation theContext = lastCallee.caller;
+
 	while (theContext != null) {
 	    if (theContext.isMarkedSpecial()) {
 		if ((findHandleContext == STObject.True)
 		    && theContext.isMarkedForHandle()) {
+		    theContext = lastCallee.sender();   // exposed
 		    return __c__._RETURN(theContext);
 		}
 		if ((findRaiseContext == STObject.True)
 		    && theContext.isMarkedForRaise()) {
+		    theContext = lastCallee.sender();   // exposed
 		    return __c__._RETURN(theContext);
 		}
 	    }
-	    theContext = theContext.sender();
+	    lastCallee = theContext;
+	    theContext = lastCallee.caller;
 	}
     }
 #else
@@ -2622,8 +2647,8 @@
 
 canResume
     "return true, if the receiver allows to be resumed.
-     Due to the implementation, this requires that the context which
-     is right below the receiver is returnable."
+     In ST/X, due to the implementation, this requires that the context which
+     is right below the receiver is returnable and still active."
 
     |theContext|
 
@@ -2633,6 +2658,7 @@
     "
 %{
 #ifdef __SCHTEAM__
+    // in the SCHTEAM-engine, all contexts are resumable
     return context._RETURN_true();
 #else
     OBJ sndr;
@@ -2666,10 +2692,16 @@
      non returnable, unless a return-pragma was present in the method.
      Since this saves some administrative work in every method
      invocation and makes overall execution faster, the system classes
-     are all compiled with this flag turned on."
+     are all compiled with this flag turned on.
+     This means, that by default, it is not possible to walk up the
+     calling chain and return to an arbitrary context.
+     For contexts which are known to require this (i.e. handlers as found
+     by the exception walkers, these are marked specially (markForReturn),
+     so compilers know that they should create full featured contexts."
 
 %{  /* NOCONTEXT */
 #ifdef __SCHTEAM__
+    // in the SCHTEAM-engine, all contexts can be returned from
     return context._RETURN_true();
 #else
     RETURN ( ((INT)(__INST(flags)) & __MASKSMALLINT(__CANNOT_RETURN)) ? false : true );
@@ -2694,7 +2726,7 @@
 
 %{  /* NOCONTEXT */
 #ifdef __SCHTEAM__
-    ERROR("unimplemented");
+    return __c__._RETURN ( ((STContinuation)self).isMarkedForHandle() );
 #else
      RETURN ( ((INT)__INST(flags) & __MASKSMALLINT(__HANDLE_MARK)) ? true : false );
 #endif
@@ -2706,12 +2738,12 @@
      A nonLifo context is one that is still on the machine stack,
      but has a reference taken and needs to be converted to a real
      object (in objectMemory) when the method/block returns.
-     You dont have to understand this - this is a special ST/X
+     You don't have to understand this - this is a special ST/X
      debug query, which may be removed without notice."
 
 %{  /* NOCONTEXT */
 #ifdef __SCHTEAM__
-    ERROR("unimplemented");
+    return __c__._RETURN ( ((STContinuation)self).isNonLifo() );
 #else
      RETURN ( ((INT)__INST(flags) & __MASKSMALLINT(__NONLIFO)) ? true : false );
 #endif
@@ -2720,15 +2752,15 @@
 
 isOnMachineStack
     "return true, if this is a machine stack context as opposed to a
-     real heap context.
-     You dont have to understand this - this is a special ST/X
+     real heap context (i.e. if it has not been captured and returned from).
+     You don't have to understand this - this is a special ST/X
      debug query, which may be removed without notice."
 
 %{  /* NOCONTEXT */
 #ifdef __SCHTEAM__
-    ERROR("unimplemented");
+    return __c__._RETURN ( ! ((STContinuation)self).isCopiedToHeap() );
 #else
-     RETURN ( (__qSpace(self) >= STACKSPACE) ? true : false );
+    RETURN ( (__qSpace(self) >= STACKSPACE) ? true : false );
 #endif
 %}
 !
@@ -2738,9 +2770,9 @@
 
 %{  /* NOCONTEXT */
 #ifdef __SCHTEAM__
-    ERROR("unimplemented");
+    return __c__._RETURN ( ((STContinuation)self).isMarkedForRaise() );
 #else
-     RETURN ( ((INT)__INST(flags) & __MASKSMALLINT(__RAISE_MARK)) ? true : false );
+    RETURN ( ((INT)__INST(flags) & __MASKSMALLINT(__RAISE_MARK)) ? true : false );
 #endif
 %}
 !
@@ -2750,9 +2782,9 @@
 
 %{  /* NOCONTEXT */
 #ifdef __SCHTEAM__
-    ERROR("unimplemented");
+    return __c__._RETURN ( ((STContinuation)self).isMarkedSpecial() );
 #else
-     RETURN ( ((INT)__INST(flags) & __MASKSMALLINT(__SPECIAL)) ? true : false );
+    RETURN ( ((INT)__INST(flags) & __MASKSMALLINT(__SPECIAL)) ? true : false );
 #endif
 %}
 !
@@ -2762,9 +2794,9 @@
 
 %{  /* NOCONTEXT */
 #ifdef __SCHTEAM__
-    ERROR("unimplemented");
+    return __c__._RETURN ( ((STContinuation)self).isMarkedForUnwind() );
 #else
-     RETURN ( ((INT)__INST(flags) & __MASKSMALLINT(__UNWIND_MARK)) ? true : false );
+    RETURN ( ((INT)__INST(flags) & __MASKSMALLINT(__UNWIND_MARK)) ? true : false );
 #endif
 %}
 !
@@ -2890,11 +2922,11 @@
 !Context class methodsFor:'documentation'!
 
 version
-    ^ '$Header: /cvs/stx/stx/libbasic/Context.st,v 1.223 2015-05-26 18:55:30 cg Exp $'
+    ^ '$Header: /cvs/stx/stx/libbasic/Context.st,v 1.224 2015-05-27 19:09:55 cg Exp $'
 !
 
 version_CVS
-    ^ '$Header: /cvs/stx/stx/libbasic/Context.st,v 1.223 2015-05-26 18:55:30 cg Exp $'
+    ^ '$Header: /cvs/stx/stx/libbasic/Context.st,v 1.224 2015-05-27 19:09:55 cg Exp $'
 !
 
 version_HG

--- a/Method.st	Wed May 27 06:37:28 2015 +0200
+++ b/Method.st	Thu May 28 06:50:45 2015 +0200
@@ -947,9 +947,12 @@
 !
 
 annotations
+    "return (a copy) of the annotations array"
+
     | retval |
 
     annotations isNil ifTrue:[^ #()].
+
     retval := Array new: annotations size.
     1 to: annotations size do: [:i|
         retval at: i put: (self annotationAtIndex: i).
@@ -1994,11 +1997,14 @@
 
 annotationAtIndex: index
     "return the annotation at given index.
-     any raw annotation array is lazily initialized"
+     any raw annotation array (as generated by the compiler)
+     is lazily initialized from the 2-element format to real annotation instances here.
+     This is done to avoid the need for knowledge about annotation instances in the stc compiler."
 
     | annotationOrArray annotation args |
 
     annotations isNil ifTrue:[^nil].
+
     annotationOrArray := annotation := annotations at: index.
     annotationOrArray isArray ifTrue:[
         args := annotationOrArray size == 2
@@ -3904,11 +3910,11 @@
 !Method class methodsFor:'documentation'!
 
 version
-    ^ '$Header: /cvs/stx/stx/libbasic/Method.st,v 1.460 2015-05-18 15:19:10 cg Exp $'
+    ^ '$Header: /cvs/stx/stx/libbasic/Method.st,v 1.461 2015-05-27 14:28:15 cg Exp $'
 !
 
 version_CVS
-    ^ '$Header: /cvs/stx/stx/libbasic/Method.st,v 1.460 2015-05-18 15:19:10 cg Exp $'
+    ^ '$Header: /cvs/stx/stx/libbasic/Method.st,v 1.461 2015-05-27 14:28:15 cg Exp $'
 !
 
 version_SVN

--- a/SmallInteger.st	Wed May 27 06:37:28 2015 +0200
+++ b/SmallInteger.st	Thu May 28 06:50:45 2015 +0200
@@ -1871,12 +1871,18 @@
 
 %{  /* NOCONTEXT */
 #ifdef __SCHTEAM__
-    int idx = index.intValue() - 1;
-
-    if (idx <= 7) {
-	int byteVal = (int)((self.longValue() >> (idx * 8)) & 0xFF);
-
-	return context._RETURN( STInteger._new(byteVal) );
+    int idx0Based = index.intValue() - 1;
+
+    if (idx0Based <= 7) {
+	long myVal = self.longValue();
+	if (myVal < 0) {
+	    myVal = -myVal;
+	}
+	int byteVal = (int)((myVal >> (idx0Based * 8)) & 0xFF);
+	return __c__._RETURN( STInteger._qnew(byteVal) );
+    }
+    if (idx0Based > 0) {
+	return __c__._RETURN( STInteger._0 );
     }
 #else
     REGISTER INT val;
@@ -1945,7 +1951,22 @@
      for negative ones, the actual bit representation is returned."
 
 %{  /* NOCONTEXT */
-#ifndef __SCHTEAM__
+#ifdef __SCHTEAM__
+    int idx0Based = index.intValue() - 1;
+    long myVal = self.longValue();
+
+    if (idx0Based <= 7) {
+	int byteVal = (int)((myVal >> (idx0Based * 8)) & 0xFF);
+	return __c__._RETURN( STInteger._qnew(byteVal) );
+    }
+    if (idx0Based > 0) {
+	if (myVal < 0) {
+	    return __c__._RETURN( STInteger._M1 );
+	} else {
+	    return __c__._RETURN( STInteger._0 );
+	}
+    }
+#else
     REGISTER INT val;
     INT idx;
 
@@ -2007,7 +2028,7 @@
 !
 
 digitBytes
-    "return a byteArray filled with the receivers bits
+    "return a byteArray filled with the receiver's bits
      (8 bits of the absolute value per element),
      least significant byte is first"
 
@@ -2115,7 +2136,7 @@
 !
 
 digitBytesMSB
-    "return a byteArray filled with the receivers bits
+    "return a byteArray filled with the receiver's bits
      (8 bits of the absolute value per element),
      most significant byte is first"
 
@@ -2228,44 +2249,57 @@
      is returned."
 
 %{  /* NOCONTEXT */
-#ifndef __SCHTEAM__
+#ifdef __SCHTEAM__
+    long val = self.longValue();
+    int offs = 0;
+
+    if (val < 0) val = -val;
+    if ((val & 0xFFFFFFFF00000000L) != 0) {
+	val >>= 32;
+	offs = 4;
+    }
+    if ((val & 0xFFFF0000) != 0) {
+	if ((val & 0xFF000000) != 0) {
+	    offs += 4;
+	} else {
+	    offs += 3;
+	}
+    } else {
+	if ((val & 0x0000FF00)!= 0) {
+	    offs += 2;
+	} else {
+	    offs += 1;
+	}
+    }
+    return __c__._RETURN( STInteger._qnew(offs) );
+#else
     INT val = __intVal(self);
+    int offs = 0;
 
     if (val < 0) {
 	val = -val;
     }
 # if __POINTER_SIZE__ == 8
     if (val & 0xFFFFFFFF00000000L) {
-	if (val & 0xFFFF000000000000L) {
-	    if (val & 0xFF00000000000000L) {
-		RETURN ( __mkSmallInteger(8));
-	    } else {
-		RETURN ( __mkSmallInteger(7));
-	    }
-	} else {
-	    if (val & 0x0000FF0000000000L) {
-		RETURN ( __mkSmallInteger(6));
-	    } else {
-		RETURN ( __mkSmallInteger(5));
-	    }
-	}
+	val >>= 32;
+	offs = 4;
     }
 # endif
 
     if (val & 0xFFFF0000) {
 	if (val & 0xFF000000) {
-	    RETURN ( __mkSmallInteger(4));
+	    RETURN ( __mkSmallInteger(4+offs));
 	} else {
-	    RETURN ( __mkSmallInteger(3));
+	    RETURN ( __mkSmallInteger(3+offs));
 	}
     } else {
 	if (val & 0x0000FF00) {
-	    RETURN ( __mkSmallInteger(2));
+	    RETURN ( __mkSmallInteger(2+offs));
 	} else {
-	    RETURN ( __mkSmallInteger(1));
+	    RETURN ( __mkSmallInteger(1+offs));
 	}
     }
-#endif
+#endif /* not SCHTEAM */
 %}.
     ^ self abs highBit - 1 // 8 + 1
 
@@ -2589,7 +2623,7 @@
 
 %{  /* NOCONTEXT */
 #ifdef __SCHTEAM__
-    return context._RETURN( self.eqP( aNumber ));
+    return context._RETURN( self.eqvP( aNumber ));
 #else
 
     if (aNumber == self) {
@@ -2766,7 +2800,7 @@
 
 %{  /* NOCONTEXT */
 #ifdef __SCHTEAM__
-    return context._RETURN( (self.eqP( aNumber ) == STObject.True) ? STObject.False : STObject.True);
+    return context._RETURN( (self.eqvP( aNumber ) == STObject.True) ? STObject.False : STObject.True);
     /* NOTREACHED */
 #else
 
@@ -3743,12 +3777,17 @@
 asBCD
     "return an integer which represents the BCD encoded value of the receiver;
      that is: each digit of its decimal representation is placed into a nibble
-     of the result. (aka 162 -> 0x162).
+     of the result. (aka 162 -> 0x162). The BCD hex string looks like the original decimal.
      This conversion is useful for some communication protocols,
      or control systems, which represent numbers this way..."
 
 %{  /* NOCONTEXT */
 #ifndef __SCHTEAM__
+    // the following code is a leftover from times when division was expensive;
+    // in modern cpu's, conditional branches are often more expensive than divisions,
+    // so it is questionable, if the effort below is still worth it.
+    // (and asBCD is really used seldom in some serial communication protocols
+    // for control systems)
     int i;
     INT _10000000s = 0, _1000000s = 0;
     INT _100000s = 0, _10000s = 0, _1000s = 0;
@@ -4941,11 +4980,11 @@
 !SmallInteger class methodsFor:'documentation'!
 
 version
-    ^ '$Header: /cvs/stx/stx/libbasic/SmallInteger.st,v 1.238 2015-05-24 12:52:47 cg Exp $'
+    ^ '$Header: /cvs/stx/stx/libbasic/SmallInteger.st,v 1.239 2015-05-27 12:49:13 cg Exp $'
 !
 
 version_CVS
-    ^ '$Header: /cvs/stx/stx/libbasic/SmallInteger.st,v 1.238 2015-05-24 12:52:47 cg Exp $'
+    ^ '$Header: /cvs/stx/stx/libbasic/SmallInteger.st,v 1.239 2015-05-27 12:49:13 cg Exp $'
 ! !