diff --git a/src/thingdef/thingdef.cpp b/src/thingdef/thingdef.cpp
index 4e526665d9..b22e558d36 100644
--- a/src/thingdef/thingdef.cpp
+++ b/src/thingdef/thingdef.cpp
@@ -286,42 +286,59 @@ static void FinishThingdef()
 	for (i = 0; i < StateTempCalls.Size(); ++i)
 	{
 		FStateTempCall *tcall = StateTempCalls[i];
-		FCompileContext ctx(tcall->ActorInfo->Class, true);
-		for (j = 0; j < tcall->Parameters.Size(); ++j)
+		VMFunction *func;
+
+		assert(tcall->Function != NULL);
+		if (tcall->Parameters.Size() == 0)
 		{
-			tcall->Parameters[j]->Resolve(ctx);
+			func = tcall->Function;
 		}
-		VMFunctionBuilder buildit;
-		// Allocate registers used to pass parameters in.
-		// self, stateowner, state, statecalldata (all are pointers)
-		buildit.Registers[REGT_POINTER].Get(4);
-		// Emit code for action parameters.
-		for (j = 0; j < tcall->Parameters.Size(); ++j)
+		else
 		{
-			FxExpression *p = /*new FxParameter*/(tcall->Parameters[j]);
-			p->Emit(&buildit);
-			delete p;
+			FCompileContext ctx(tcall->ActorInfo->Class, true);
+			for (j = 0; j < tcall->Parameters.Size(); ++j)
+			{
+				tcall->Parameters[j]->Resolve(ctx);
+			}
+			VMFunctionBuilder buildit;
+			// Allocate registers used to pass parameters in.
+			// self, stateowner, state, statecalldata (all are pointers)
+			buildit.Registers[REGT_POINTER].Get(4);
+			// Emit code to pass the standard action function parameters.
+			buildit.Emit(OP_PARAM, 0, REGT_POINTER, 0);
+			buildit.Emit(OP_PARAM, 0, REGT_POINTER, 1);
+			buildit.Emit(OP_PARAM, 0, REGT_POINTER, 2);
+			buildit.Emit(OP_PARAM, 0, REGT_POINTER, 3);
+			// Emit code for action parameters.
+			for (j = 0; j < tcall->Parameters.Size(); ++j)
+			{
+				FxExpression *p = /*new FxParameter*/(tcall->Parameters[j]);
+				p->Emit(&buildit);
+				delete p;
+			}
+			buildit.Emit(OP_CALL_K, buildit.GetConstantAddress(tcall->Function, ATAG_OBJECT), NAP + j, 0);
+			buildit.Emit(OP_RET, 0, REGT_NIL, 0);
+			VMScriptFunction *sfunc = buildit.MakeFunction();
+			sfunc->NumArgs = NAP;
+			func = sfunc;
+#if 1
+			const char *marks = "=======================================================";
+			char label[64];
+			int labellen = mysnprintf(label, countof(label), "Function %s.States[%d] (*%d)",
+				tcall->ActorInfo->Class->TypeName.GetChars(),
+				tcall->FirstState, tcall->NumStates);
+			fprintf(dump, "\n%.*s %s %.*s", MAX(3, 38 - labellen / 2), marks, label, MAX(3, 38 - labellen / 2), marks);
+			fprintf(dump, "\nInteger regs: %-3d  Float regs: %-3d  Address regs: %-3d  String regs: %-3d\nStack size: %d\n",
+				sfunc->NumRegD, sfunc->NumRegF, sfunc->NumRegA, sfunc->NumRegS, sfunc->MaxParam);
+			VMDumpConstants(dump, sfunc);
+			fprintf(dump, "\nDisassembly @ %p:\n", sfunc->Code);
+			VMDisasm(dump, sfunc->Code, sfunc->CodeSize, sfunc);
+#endif
 		}
-		buildit.Emit(OP_CALL_K, buildit.GetConstantAddress(NULL, ATAG_OBJECT), j, 0);
-		VMScriptFunction *func = buildit.MakeFunction();
-		func->NumArgs = tcall->Parameters.Size();
 		for (int k = 0; k < tcall->NumStates; ++k)
 		{
 			tcall->ActorInfo->OwnedStates[tcall->FirstState + k].SetAction(func);
 		}
-#if 1
-		const char *marks = "=======================================================";
-		char label[64];
-		int labellen = mysnprintf(label, countof(label), "Function %s.States[%d] (*%d)",
-			tcall->ActorInfo->Class->TypeName.GetChars(),
-			tcall->FirstState, tcall->NumStates);
-		fprintf(dump, "\n%.*s %s %.*s", MAX(3, 38 - labellen / 2), marks, label, MAX(3, 38 - labellen / 2), marks);
-		fprintf(dump, "\nInteger regs: %-3d  Float regs: %-3d  Address regs: %-3d  String regs: %-3d\nStack size: %d\n",
-			func->NumRegD, func->NumRegF, func->NumRegA, func->NumRegS, func->MaxParam);
-		VMDumpConstants(dump, func);
-		fprintf(dump, "\nDisassembly:\n");
-		VMDisasm(dump, func->Code, func->CodeSize, func);
-#endif
 	}
 	fclose(dump);
 
diff --git a/src/thingdef/thingdef.h b/src/thingdef/thingdef.h
index 60ff50620f..4829cc306b 100644
--- a/src/thingdef/thingdef.h
+++ b/src/thingdef/thingdef.h
@@ -111,10 +111,13 @@ public:
 
 struct FStateTempCall
 {
+	FStateTempCall() : ActorInfo(NULL), Function(NULL), FirstState(0), NumStates(0) {}
+
 	FActorInfo *ActorInfo;
+	VMFunction *Function;
+	TArray<FxExpression *> Parameters;
 	int FirstState;
 	int NumStates;
-	TArray<FxExpression *> Parameters;
 };
 extern TDeletingArray<FStateTempCall *> StateTempCalls;
 
@@ -386,7 +389,7 @@ struct StateCallData
 //#define PUSH_PARAMINFO self, stateowner, CallingState, ParameterIndex, statecall
 
 #define CALL_ACTION(name,self) { /*AF_##name(self, self, NULL, 0, NULL)*/ \
-		VMValue params[5] = { self, self, NULL, VMValue(NULL, ATAG_STATE) }; \
+		VMValue params[5] = { self, self, VMValue(NULL, ATAG_STATE), VMValue(NULL, ATAG_GENERIC) }; \
 		stack->Call(name##_VMPtr, params, countof(params), NULL, 0, NULL); \
 	}
 
diff --git a/src/thingdef/thingdef_codeptr.cpp b/src/thingdef/thingdef_codeptr.cpp
index 9da7ff3b51..c12f41a527 100644
--- a/src/thingdef/thingdef_codeptr.cpp
+++ b/src/thingdef/thingdef_codeptr.cpp
@@ -452,11 +452,12 @@ DEFINE_ACTION_FUNCTION_PARAMS(AActor, A_Jump)
 	PARAM_ACTION_PROLOGUE;
 	PARAM_INT_OPT(maxchance) { maxchance = 256; }
 
-	int count = numparam - pnum;
+	paramnum++;		// Increment paramnum to point at the first jump target
+	int count = numparam - paramnum;
 	if (count > 0 && (maxchance >= 256 || pr_cajump() < maxchance))
 	{
 		int jumpnum = (count == 1 ? 0 : (pr_cajump() % count));
-		PARAM_STATE_AT(pnum + jumpnum, jumpto);
+		PARAM_STATE_AT(paramnum + jumpnum, jumpto);
 		ACTION_JUMP(jumpto);
 	}
 	ACTION_SET_RESULT(false);	// Jumps should never set the result for inventory state chains!
@@ -529,7 +530,7 @@ DEFINE_ACTION_FUNCTION_PARAMS(AActor, A_JumpIfCloser)
 //==========================================================================
 void DoJumpIfInventory(AActor *owner, AActor *self, StateCallData *statecall, FState *callingstate, VMValue *param, int numparam)
 {
-	int pnum = NAP;
+	int paramnum = NAP-1;
 	PARAM_CLASS	(itemtype, AInventory);
 	PARAM_INT	(itemamount);
 	PARAM_STATE	(label);
@@ -1314,7 +1315,7 @@ DEFINE_ACTION_FUNCTION_PARAMS(AActor, A_CustomRailgun)
 
 static void DoGiveInventory(AActor *receiver, StateCallData *statecall, VM_ARGS)
 {
-	int pnum = NAP;
+	int paramnum = NAP-1;
 	PARAM_CLASS		(mi, AInventory);
 	PARAM_INT_OPT	(amount)			{ amount = 1; }
 
@@ -1381,7 +1382,7 @@ DEFINE_ACTION_FUNCTION_PARAMS(AActor, A_GiveToTarget)
 
 void DoTakeInventory(AActor *receiver, StateCallData *statecall, VM_ARGS)
 {
-	int pnum = NAP;
+	int paramnum = NAP-1;
 	PARAM_CLASS		(itemtype, AInventory);
 	PARAM_INT_OPT	(amount)		{ amount = 0; }
 	
diff --git a/src/thingdef/thingdef_expression.cpp b/src/thingdef/thingdef_expression.cpp
index 7b32a132f1..5167bba6a5 100644
--- a/src/thingdef/thingdef_expression.cpp
+++ b/src/thingdef/thingdef_expression.cpp
@@ -3735,7 +3735,7 @@ int DecoNameToClass(VMFrameStack *stack, VMValue *param, int numparam, VMReturn
 		Printf("class '%s' is not compatible with '%s'", clsname.GetChars(), desttype->TypeName.GetChars());
 		cls = NULL;
 	}
-	ret->SetPointer(const_cast<PClass *>(cls));
+	ret->SetPointer(const_cast<PClass *>(cls), ATAG_OBJECT);
 	return 1;
 }
 
@@ -3923,15 +3923,15 @@ int DecoFindMultiNameState(VMFrameStack *stack, VMValue *param, int numparam, VM
 {
 	assert(numparam > 1);
 	assert(numret == 1);
-	assert(param[0].Type == REGT_POINTER);
 	assert(ret->RegType == REGT_POINTER);
 
 	FName *names = (FName *)alloca((numparam - 1) * sizeof(FName));
 	for (int i = 1; i < numparam; ++i)
 	{
-		names[i - 1] = ENamedName(param[i].i);
+		PARAM_NAME_AT(i, zaname);
+		names[i - 1] = zaname;
 	}
-	AActor *self = reinterpret_cast<AActor *>(param[0].a);
+	PARAM_OBJECT_AT(0, self, AActor);
 	FState *state = self->GetClass()->ActorInfo->FindState(numparam - 1, names);
 	if (state == NULL)
 	{
@@ -3944,14 +3944,14 @@ int DecoFindMultiNameState(VMFrameStack *stack, VMValue *param, int numparam, VM
 		}
 		Printf("' not found in %s\n", self->GetClass()->TypeName.GetChars());
 	}
-	ret->SetPointer(state);
+	ret->SetPointer(state, ATAG_STATE);
 	return 1;
 }
 
 ExpEmit FxMultiNameState::Emit(VMFunctionBuilder *build)
 {
 	ExpEmit dest(build, REGT_POINTER);
-	build->Emit(OP_PARAM, 0, REGT_POINTER, 0);		// pass self
+	build->Emit(OP_PARAM, 0, REGT_POINTER, 1);		// pass stateowner
 	for (unsigned i = 0; i < names.Size(); ++i)
 	{
 		EmitConstantInt(build, names[i]);
diff --git a/src/thingdef/thingdef_states.cpp b/src/thingdef/thingdef_states.cpp
index a27bd48d31..208581b516 100644
--- a/src/thingdef/thingdef_states.cpp
+++ b/src/thingdef/thingdef_states.cpp
@@ -81,7 +81,7 @@ bool DoActionSpecials(FScanner &sc, FState & state, Baggage &bag, FStateTempCall
 		{
 			for (i = 0; i < 5;)
 			{
-				tcall->Parameters.Push(new FxParameter(ParseExpression(sc, bag.Info->Class)));
+				tcall->Parameters.Push(new FxParameter(new FxIntCast(ParseExpression(sc, bag.Info->Class))));
 				i++;
 				if (!sc.CheckToken (',')) break;
 			}
@@ -98,8 +98,7 @@ bool DoActionSpecials(FScanner &sc, FState & state, Baggage &bag, FStateTempCall
 			sc.ScriptError ("Too many arguments to %s", specname.GetChars());
 		}
 
-		//FIXME
-		//state.SetAction(FindGlobalActionFunction("A_CallSpecial"), false);
+		tcall->Function = FindGlobalActionFunction("A_CallSpecial")->Function;
 		return true;
 	}
 	return false;
@@ -262,6 +261,7 @@ do_stop:
 				if (sym != NULL && sym->SymbolType == SYM_ActionFunction)
 				{
 					PSymbolActionFunction *afd = static_cast<PSymbolActionFunction *>(sym);
+					tcall->Function = afd->Function;
 					if (!afd->Arguments.IsEmpty())
 					{
 						const char *params = afd->Arguments.GetChars();
@@ -374,7 +374,7 @@ endofstate:
 				sc.ScriptError ("Invalid frame character string '%s'", statestring.GetChars());
 				count = -count;
 			}
-			if (tcall->Parameters.Size() != 0)
+			if (tcall->Function != NULL)
 			{
 				tcall->ActorInfo = actor;
 				tcall->FirstState = bag.statedef.GetStateCount() - count;
diff --git a/src/zscript/vm.h b/src/zscript/vm.h
index 21a67188e4..72e2141d58 100644
--- a/src/zscript/vm.h
+++ b/src/zscript/vm.h
@@ -251,54 +251,63 @@ extern const VMOpInfo OpInfo[NUM_OPS];
 struct VMReturn
 {
 	void *Location;
-	VM_SHALF RegNum;	// Used to find ObjFlag index for pointers; set negative if the caller is native code and doesn't care
+	VM_SHALF TagOfs;	// for pointers: Offset from Location to ATag; set to 0 if the caller is native code and doesn't care
 	VM_UBYTE RegType;	// Same as VMParam RegType, except REGT_KONST is invalid; only used by asserts
 
 	void SetInt(int val)
 	{
+		assert(RegType == REGT_INT);
 		*(int *)Location = val;
 	}
 	void SetFloat(double val)
 	{
+		assert(RegType == REGT_FLOAT);
 		*(double *)Location = val;
 	}
 	void SetVector(const double val[3])
-	{
+	{	
+		//assert(RegType == REGT_FLOAT);
 		((double *)Location)[0] = val[0];
 		((double *)Location)[1] = val[1];
 		((double *)Location)[2] = val[2];
 	}
 	void SetString(const FString &val)
 	{
+		assert(RegType == REGT_STRING);
 		*(FString *)Location = val;
 	}
-	void SetPointer(void *val)
+	void SetPointer(void *val, int tag)
 	{
+		assert(RegType == REGT_POINTER);
 		*(void **)Location = val;
+		if (TagOfs != 0)
+		{
+			*((VM_ATAG *)Location + TagOfs) = tag;
+		}
 	}
 
 	void IntAt(int *loc)
 	{
 		Location = loc;
-		RegNum = -1;
+		TagOfs = 0;
 		RegType = REGT_INT;
 	}
 	void FloatAt(double *loc)
 	{
 		Location = loc;
-		RegNum = -1;
+		TagOfs = 0;
 		RegType = REGT_FLOAT;
 	}
 	void StringAt(FString *loc)
 	{
 		Location = loc;
-		RegNum = -1;
+		TagOfs = 0;
 		RegType = REGT_STRING;
 	}
 	void PointerAt(void **loc)
 	{
 		Location = loc;
-		RegNum = -1;
+		TagOfs = 0;
 		RegType = REGT_POINTER;
 	}
 };
@@ -863,8 +872,8 @@ void VMDisasm(FILE *out, const VMOP *code, int codesize, const VMScriptFunction
 #define PARAM_STRING_AT(p,x)		assert((p) < numparam); assert(param[p].Type == REGT_STRING); FString x = param[p].s();
 #define PARAM_STATE_AT(p,x)			assert((p) < numparam); assert(param[p].Type == REGT_POINTER && (param[p].atag == ATAG_STATE || param[p].a == NULL)); FState *x = (FState *)param[p].a;
 #define PARAM_POINTER_AT(p,x,type)	assert((p) < numparam); assert(param[p].Type == REGT_POINTER); type *x = (type *)param[p].a;
-#define PARAM_OBJECT_AT(p,x,type)	assert((p) < numparam); assert(param[p].Type == REGT_POINTER && (param[p].atag == ATAG_OBJECT || param[p].a == NULL)); type *x = (type *)param[p].a;
-#define PARAM_CLASS_AT(p,x,base)	assert((p) < numparam); assert(param[p].Type == REGT_POINTER && (param[p].atag == ATAG_OBJECT || param[p].a == NULL)); PClass *x = (PClass *)param[p].a; assert(x->IsDescendantOf(RUNTIME_CLASS(base)));
+#define PARAM_OBJECT_AT(p,x,type)	assert((p) < numparam); assert(param[p].Type == REGT_POINTER && (param[p].atag == ATAG_OBJECT || param[p].a == NULL)); type *x = (type *)param[p].a; assert(x == NULL || x->IsKindOf(RUNTIME_CLASS(type)));
+#define PARAM_CLASS_AT(p,x,base)	assert((p) < numparam); assert(param[p].Type == REGT_POINTER && (param[p].atag == ATAG_OBJECT || param[p].a == NULL)); PClass *x = (PClass *)param[p].a; assert(x != NULL && x->IsDescendantOf(RUNTIME_CLASS(base)));
 
 // For optional paramaters. These have dangling elses for you to fill in the default assignment. e.g.:
 //		PARAM_INT_OPT(0,myint) { myint = 55; }
@@ -881,38 +890,38 @@ void VMDisasm(FILE *out, const VMOP *code, int codesize, const VMScriptFunction
 #define PARAM_STRING_OPT_AT(p,x)		FString x; if ((p) < numparam && param[p].Type != REGT_NIL) { assert(param[p].Type == REGT_STRING); x = param[p].s(); } else
 #define PARAM_STATE_OPT_AT(p,x)			FState *x; if ((p) < numparam && param[p].Type != REGT_NIL) { assert(param[p].Type == REGT_POINTER && (param[p].atag == ATAG_STATE || param[p].a == NULL)); x = (FState *)param[p].a; } else
 #define PARAM_POINTER_OPT_AT(p,x,type)	type *x; if ((p) < numparam && param[p].Type != REGT_NIL) { assert(param[p].Type == REGT_POINTER); x = (type *)param[p].a; } else
-#define PARAM_OBJECT_OPT_AT(p,x,type)	type *x; if ((p) < numparam && param[p].Type != REGT_NIL) { assert(param[p].Type == REGT_POINTER && (param[p].atag == ATAG_OBJECT || param[p].a == NULL)); x = (type *)param[p].a; } else
-#define PARAM_CLASS_OPT_AT(p,x,base)	PClass *x; if ((p) < numparam && param[p].Type != REGT_NIL) { assert(param[p].Type == REGT_POINTER && (param[p].atag == ATAG_OBJECT || param[p].a == NULL)); x = (PClass *)param[p].a; assert(x->IsKindOf(RUNTIME_CLASS(base))); } else
+#define PARAM_OBJECT_OPT_AT(p,x,type)	type *x; if ((p) < numparam && param[p].Type != REGT_NIL) { assert(param[p].Type == REGT_POINTER && (param[p].atag == ATAG_OBJECT || param[p].a == NULL)); x = (type *)param[p].a; assert(x == NULL || x->IsKindOf(RUNTIME_CLASS(type))); } else
+#define PARAM_CLASS_OPT_AT(p,x,base)	PClass *x; if ((p) < numparam && param[p].Type != REGT_NIL) { assert(param[p].Type == REGT_POINTER && (param[p].atag == ATAG_OBJECT || param[p].a == NULL)); x = (PClass *)param[p].a; assert(x != NULL && x->IsDescendantOf(RUNTIME_CLASS(base))); } else
 
 // The above, but with an automatically increasing position index.
-#define PARAM_PROLOGUE				int pnum = -1;
+#define PARAM_PROLOGUE				int paramnum = -1;
 
-#define PARAM_INT(x)				++pnum; PARAM_INT_AT(pnum,x)
-#define PARAM_BOOL(x)				++pnum; PARAM_BOOL_AT(pnum,x)
-#define PARAM_NAME(x)				++pnum; PARAM_NAME_AT(pnum,x)
-#define PARAM_SOUND(x)				++pnum; PARAM_SOUND_AT(pnum,x)
-#define PARAM_COLOR(x)				++pnum; PARAM_COLOR_AT(pnum,x)
-#define PARAM_FLOAT(x)				++pnum; PARAM_FLOAT_AT(pnum,x)
-#define PARAM_FIXED(x)				++pnum; PARAM_FIXED_AT(pnum,x)
-#define PARAM_ANGLE(x)				++pnum; PARAM_ANGLE_AT(pnum,x)
-#define PARAM_STRING(x)				++pnum; PARAM_STRING_AT(pnum,x)
-#define PARAM_STATE(x)				++pnum; PARAM_STATE_AT(pnum,x)
-#define PARAM_POINTER(x,type)		++pnum; PARAM_POINTER_AT(pnum,x,type)
-#define PARAM_OBJECT(x,type)		++pnum; PARAM_OBJECT_AT(pnum,x,type)
-#define PARAM_CLASS(x,base)			++pnum; PARAM_CLASS_AT(pnum,x,base)
+#define PARAM_INT(x)				++paramnum; PARAM_INT_AT(paramnum,x)
+#define PARAM_BOOL(x)				++paramnum; PARAM_BOOL_AT(paramnum,x)
+#define PARAM_NAME(x)				++paramnum; PARAM_NAME_AT(paramnum,x)
+#define PARAM_SOUND(x)				++paramnum; PARAM_SOUND_AT(paramnum,x)
+#define PARAM_COLOR(x)				++paramnum; PARAM_COLOR_AT(paramnum,x)
+#define PARAM_FLOAT(x)				++paramnum; PARAM_FLOAT_AT(paramnum,x)
+#define PARAM_FIXED(x)				++paramnum; PARAM_FIXED_AT(paramnum,x)
+#define PARAM_ANGLE(x)				++paramnum; PARAM_ANGLE_AT(paramnum,x)
+#define PARAM_STRING(x)				++paramnum; PARAM_STRING_AT(paramnum,x)
+#define PARAM_STATE(x)				++paramnum; PARAM_STATE_AT(paramnum,x)
+#define PARAM_POINTER(x,type)		++paramnum; PARAM_POINTER_AT(paramnum,x,type)
+#define PARAM_OBJECT(x,type)		++paramnum; PARAM_OBJECT_AT(paramnum,x,type)
+#define PARAM_CLASS(x,base)			++paramnum; PARAM_CLASS_AT(paramnum,x,base)
 
-#define PARAM_INT_OPT(x)			++pnum; PARAM_INT_OPT_AT(pnum,x)
-#define PARAM_BOOL_OPT(x)			++pnum; PARAM_BOOL_OPT_AT(pnum,x)
-#define PARAM_NAME_OPT(x)			++pnum; PARAM_NAME_OPT_AT(pnum,x)
-#define PARAM_SOUND_OPT(x)			++pnum; PARAM_SOUND_OPT_AT(pnum,x)
-#define PARAM_COLOR_OPT(x)			++pnum; PARAM_COLOR_OPT_AT(pnum,x)
-#define PARAM_FLOAT_OPT(x)			++pnum; PARAM_FLOAT_OPT_AT(pnum,x)
-#define PARAM_FIXED_OPT(x)			++pnum; PARAM_FIXED_OPT_AT(pnum,x)
-#define PARAM_ANGLE_OPT(x)			++pnum; PARAM_ANGLE_OPT_AT(pnum,x)
-#define PARAM_STRING_OPT(x)			++pnum; PARAM_STRING_OPT_AT(pnum,x)
-#define PARAM_STATE_OPT(x)			++pnum; PARAM_STATE_OPT_AT(pnum,x)
-#define PARAM_POINTER_OPT(x,type)	++pnum; PARAM_POINTER_OPT_AT(pnum,x,type)
-#define PARAM_OBJECT_OPT(x,type)	++pnum; PARAM_OBJECT_OPT_AT(pnum,x,type)
-#define PARAM_CLASS_OPT(x,base)		++pnum; PARAM_CLASS_OPT_AT(pnum,x,base)
+#define PARAM_INT_OPT(x)			++paramnum; PARAM_INT_OPT_AT(paramnum,x)
+#define PARAM_BOOL_OPT(x)			++paramnum; PARAM_BOOL_OPT_AT(paramnum,x)
+#define PARAM_NAME_OPT(x)			++paramnum; PARAM_NAME_OPT_AT(paramnum,x)
+#define PARAM_SOUND_OPT(x)			++paramnum; PARAM_SOUND_OPT_AT(paramnum,x)
+#define PARAM_COLOR_OPT(x)			++paramnum; PARAM_COLOR_OPT_AT(paramnum,x)
+#define PARAM_FLOAT_OPT(x)			++paramnum; PARAM_FLOAT_OPT_AT(paramnum,x)
+#define PARAM_FIXED_OPT(x)			++paramnum; PARAM_FIXED_OPT_AT(paramnum,x)
+#define PARAM_ANGLE_OPT(x)			++paramnum; PARAM_ANGLE_OPT_AT(paramnum,x)
+#define PARAM_STRING_OPT(x)			++paramnum; PARAM_STRING_OPT_AT(paramnum,x)
+#define PARAM_STATE_OPT(x)			++paramnum; PARAM_STATE_OPT_AT(paramnum,x)
+#define PARAM_POINTER_OPT(x,type)	++paramnum; PARAM_POINTER_OPT_AT(paramnum,x,type)
+#define PARAM_OBJECT_OPT(x,type)	++paramnum; PARAM_OBJECT_OPT_AT(paramnum,x,type)
+#define PARAM_CLASS_OPT(x,base)		++paramnum; PARAM_CLASS_OPT_AT(paramnum,x,base)
 
 #endif
diff --git a/src/zscript/vmdisasm.cpp b/src/zscript/vmdisasm.cpp
index 9175cc096a..5e7d4e0cc0 100644
--- a/src/zscript/vmdisasm.cpp
+++ b/src/zscript/vmdisasm.cpp
@@ -155,7 +155,7 @@ void VMDumpConstants(FILE *out, const VMScriptFunction *func)
 		{
 			for (j = 0, k = i; j < 4 && k < func->NumKonstA; j++, k += kk)
 			{
-				mysnprintf(tmp, countof(tmp), "%3d. %p", k, func->KonstA[k]);
+				mysnprintf(tmp, countof(tmp), "%3d. %p:%d", k, func->KonstA[k], func->KonstATags()[k]);
 				printf_wrapper(out, "%-20s", tmp);
 			}
 			printf_wrapper(out, "\n");
diff --git a/src/zscript/vmexec.h b/src/zscript/vmexec.h
index 07809909b6..e9847946f5 100644
--- a/src/zscript/vmexec.h
+++ b/src/zscript/vmexec.h
@@ -1384,7 +1384,7 @@ static void DoCast(const VMRegisters &reg, const VMFrame *f, int a, int b, int c
 
 static void FillReturns(const VMRegisters &reg, VMFrame *frame, VMReturn *returns, const VMOP *retval, int numret)
 {
-	int i, type, num;
+	int i, type, regnum;
 	VMReturn *ret;
 
 	assert(REGT_INT == 0 && REGT_FLOAT == 1 && REGT_STRING == 2 && REGT_POINTER == 3);
@@ -1392,33 +1392,35 @@ static void FillReturns(const VMRegisters &reg, VMFrame *frame, VMReturn *return
 	for (i = 0, ret = returns; i < numret; ++i, ++ret, ++retval)
 	{
 		assert(retval->op == OP_RESULT);				// opcode
+		ret->TagOfs = 0;
 		ret->RegType = type = retval->b;
-		ret->RegNum = num = retval->c;
+		regnum = retval->c;
 		assert(!(type & REGT_KONST));
 		type &= REGT_TYPE;
 		if (type < REGT_STRING)
 		{
 			if (type == REGT_INT)
 			{
-				assert(num < frame->NumRegD);
-				ret->Location = &reg.d[num];
+				assert(regnum < frame->NumRegD);
+				ret->Location = &reg.d[regnum];
 			}
 			else // type == REGT_FLOAT
 			{
-				assert(num < frame->NumRegF);
-				ret->Location = &reg.f[num];
+				assert(regnum < frame->NumRegF);
+				ret->Location = &reg.f[regnum];
 			}
 		}
 		else if (type == REGT_STRING)
 		{
-			assert(num < frame->NumRegS);
-			ret->Location = &reg.s[num];
+			assert(regnum < frame->NumRegS);
+			ret->Location = &reg.s[regnum];
 		}
 		else
 		{
 			assert(type == REGT_POINTER);
-			assert(num < frame->NumRegA);
-			ret->Location = &reg.a[num];
+			assert(regnum < frame->NumRegA);
+			ret->Location = &reg.a[regnum];
+			ret->TagOfs = (VM_SHALF)(&frame->GetRegATag()[regnum] - (VM_ATAG *)ret->Location);
 		}
 	}
 }
@@ -1434,7 +1436,6 @@ static void FillReturns(const VMRegisters &reg, VMFrame *frame, VMReturn *return
 static void SetReturn(const VMRegisters &reg, VMFrame *frame, VMReturn *ret, VM_UBYTE regtype, int regnum)
 {
 	const void *src;
-	VM_ATAG atag;
 	VMScriptFunction *func = static_cast<VMScriptFunction *>(frame->Func);
 
 	assert(func != NULL && !func->Native);
@@ -1498,20 +1499,12 @@ static void SetReturn(const VMRegisters &reg, VMFrame *frame, VMReturn *ret, VM_
 		if (regtype & REGT_KONST)
 		{
 			assert(regnum < func->NumKonstA);
-			ret->SetPointer(func->KonstA[regnum].v);
-			atag = func->KonstATags()[regnum];
+			ret->SetPointer(func->KonstA[regnum].v, func->KonstATags()[regnum]);
 		}
 		else
 		{
 			assert(regnum < frame->NumRegA);
-			ret->SetPointer(reg.a[regnum]);
-			atag = reg.atag[regnum];
-		}
-		if (ret->RegNum >= 0)
-		{
-			VMFrame *parent = frame->ParentFrame;
-			assert(parent != NULL);
-			parent->GetRegATag()[ret->RegNum] = atag;
+			ret->SetPointer(reg.a[regnum], reg.atag[regnum]);
 		}
 		break;
 	}
diff --git a/wadsrc/static/actors/actor.txt b/wadsrc/static/actors/actor.txt
index 0bb53fa0aa..568ecf262a 100644
--- a/wadsrc/static/actors/actor.txt
+++ b/wadsrc/static/actors/actor.txt
@@ -26,7 +26,6 @@ ACTOR Actor native //: Thinker
 	native fixed_t alpha;
 	native angle_t angle;
 	native int args[5];
-	native int uservar[10];
 	native fixed_t ceilingz;
 	native fixed_t floorz;
 	native int health;