diff --git a/src/p_actionfunctions.cpp b/src/p_actionfunctions.cpp
index 43c9e45fe0..e863a442c5 100644
--- a/src/p_actionfunctions.cpp
+++ b/src/p_actionfunctions.cpp
@@ -1892,7 +1892,7 @@ EXTERN_CVAR(Float, con_midtime)
 DEFINE_ACTION_FUNCTION(AActor, A_Print)
 {
 	PARAM_SELF_PROLOGUE(AActor);
-	PARAM_STRING	(text);
+	PARAM_STRING_VAL(text);
 	PARAM_FLOAT	(time);
 	PARAM_NAME	(fontname);
 
@@ -1927,7 +1927,7 @@ DEFINE_ACTION_FUNCTION(AActor, A_Print)
 DEFINE_ACTION_FUNCTION(AActor, A_PrintBold)
 {
 	PARAM_SELF_PROLOGUE(AActor);
-	PARAM_STRING	(text);
+	PARAM_STRING_VAL	(text);
 	PARAM_FLOAT	(time);
 	PARAM_NAME	(fontname);
 
@@ -1958,7 +1958,7 @@ DEFINE_ACTION_FUNCTION(AActor, A_PrintBold)
 DEFINE_ACTION_FUNCTION(AActor, A_Log)
 {
 	PARAM_SELF_PROLOGUE(AActor);
-	PARAM_STRING(text);
+	PARAM_STRING_VAL(text);
 	PARAM_BOOL(local);
 
 	if (local && !self->CheckLocalView(consoleplayer)) return 0;
diff --git a/src/scripting/thingdef.h b/src/scripting/thingdef.h
index b26ddd1d78..33d9e7450e 100644
--- a/src/scripting/thingdef.h
+++ b/src/scripting/thingdef.h
@@ -74,7 +74,7 @@ void HandleDeprecatedFlags(AActor *defaults, PClassActor *info, bool set, int in
 bool CheckDeprecatedFlags(const AActor *actor, PClassActor *info, int index);
 const char *GetFlagName(unsigned int flagnum, int flagoffset);
 void ModActorFlag(AActor *actor, FFlagDef *fd, bool set);
-bool ModActorFlag(AActor *actor, FString &flagname, bool set, bool printerror = true);
+bool ModActorFlag(AActor *actor, const FString &flagname, bool set, bool printerror = true);
 INTBOOL CheckActorFlag(const AActor *actor, FFlagDef *fd);
 INTBOOL CheckActorFlag(const AActor *owner, const char *flagname, bool printerror = true);
 
diff --git a/src/scripting/thingdef_properties.cpp b/src/scripting/thingdef_properties.cpp
index 4d7908c6b0..a279ed070d 100644
--- a/src/scripting/thingdef_properties.cpp
+++ b/src/scripting/thingdef_properties.cpp
@@ -142,7 +142,7 @@ void ModActorFlag(AActor *actor, FFlagDef *fd, bool set)
 //
 //==========================================================================
 
-bool ModActorFlag(AActor *actor, FString &flagname, bool set, bool printerror)
+bool ModActorFlag(AActor *actor, const FString &flagname, bool set, bool printerror)
 {
 	bool found = false;
 
diff --git a/src/scripting/vm/vm.h b/src/scripting/vm/vm.h
index 8ed78b8546..98c59eb67a 100644
--- a/src/scripting/vm/vm.h
+++ b/src/scripting/vm/vm.h
@@ -511,7 +511,8 @@ bool AssertObject(void * ob);
 #define PARAM_COLOR_AT(p,x)			assert((p) < numparam); assert(reginfo[p] == REGT_INT); PalEntry x; x.d = param[p].i;
 #define PARAM_FLOAT_AT(p,x)			assert((p) < numparam); assert(reginfo[p] == REGT_FLOAT); double x = param[p].f;
 #define PARAM_ANGLE_AT(p,x)			assert((p) < numparam); assert(reginfo[p] == REGT_FLOAT); DAngle x = param[p].f;
-#define PARAM_STRING_AT(p,x)		assert((p) < numparam); assert(reginfo[p] == REGT_STRING); FString x = param[p].s();
+#define PARAM_STRING_VAL_AT(p,x)	assert((p) < numparam); assert(reginfo[p] == REGT_STRING); FString x = param[p].s();
+#define PARAM_STRING_AT(p,x)		assert((p) < numparam); assert(reginfo[p] == REGT_STRING); const FString &x = param[p].s();
 #define PARAM_STATE_AT(p,x)			assert((p) < numparam); assert(reginfo[p] == REGT_INT); FState *x = (FState *)StateLabels.GetState(param[p].i, self->GetClass());
 #define PARAM_STATE_ACTION_AT(p,x)	assert((p) < numparam); assert(reginfo[p] == REGT_INT); FState *x = (FState *)StateLabels.GetState(param[p].i, stateowner->GetClass());
 #define PARAM_POINTER_AT(p,x,type)	assert((p) < numparam); assert(reginfo[p] == REGT_POINTER); type *x = (type *)param[p].a;
@@ -536,6 +537,7 @@ bool AssertObject(void * ob);
 #define PARAM_FLOAT(x)				++paramnum; PARAM_FLOAT_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_STRING_VAL(x)				++paramnum; PARAM_STRING_VAL_AT(paramnum,x)
 #define PARAM_STATE(x)				++paramnum; PARAM_STATE_AT(paramnum,x)
 #define PARAM_STATE_ACTION(x)		++paramnum; PARAM_STATE_ACTION_AT(paramnum,x)
 #define PARAM_POINTER(x,type)		++paramnum; PARAM_POINTER_AT(paramnum,x,type)
diff --git a/src/scripting/vmthunks.cpp b/src/scripting/vmthunks.cpp
index 3b9a549474..e353eaa447 100644
--- a/src/scripting/vmthunks.cpp
+++ b/src/scripting/vmthunks.cpp
@@ -19,6 +19,13 @@
 //
 // VM thunks for internal functions.
 //
+// Important note about this file: Since everything in here is supposed to be called
+// from JIT-compiled VM code it needs to be very careful about calling conventions.
+// As a result none of the integer sized struct types may be used as function
+// arguments, because current C++ calling conventions require them to be passed
+// by reference. The JIT code, however will pass them by value so any direct native function
+// taking such an argument needs to receive it as a naked int.
+//
 //-----------------------------------------------------------------------------
 
 #include "vm.h"
@@ -26,7 +33,14 @@
 #include "g_levellocals.h"
 #include "s_sound.h"
 #include "p_local.h"
+#include "v_font.h"
+#include "gstrings.h"
 
+//=====================================================================================
+//
+// sector_t exports
+//
+//=====================================================================================
 
 DEFINE_ACTION_FUNCTION_NATIVE(_Sector, FindLowestFloorSurrounding, FindLowestFloorSurrounding)
 {
@@ -1033,7 +1047,7 @@ DEFINE_ACTION_FUNCTION_NATIVE(_Sector, RemoveForceField, RemoveForceField)
 
  //===========================================================================
  //
- // 
+ // side_t exports 
  //
  //===========================================================================
 
@@ -1281,6 +1295,7 @@ DEFINE_ACTION_FUNCTION_NATIVE(_Sector, RemoveForceField, RemoveForceField)
 
  //=====================================================================================
 //
+ // vertex_t exports
 //
 //=====================================================================================
 
@@ -1300,6 +1315,12 @@ DEFINE_ACTION_FUNCTION_NATIVE(_Sector, RemoveForceField, RemoveForceField)
 	 ACTION_RETURN_INT(VertexIndex(self));
  }
 
+ //=====================================================================================
+//
+// TexMan exports
+//
+//=====================================================================================
+
  // This is needed to convert the strings to char pointers.
  static void ReplaceTextures(const FString &from, const FString &to, int flags)
  {
@@ -1318,6 +1339,7 @@ DEFINE_ACTION_FUNCTION_NATIVE(_TexMan, ReplaceTextures, ReplaceTextures)
 
 //=====================================================================================
 //
+// secplane_t exports
 //
 //=====================================================================================
 
@@ -1445,6 +1467,104 @@ DEFINE_ACTION_FUNCTION_NATIVE(_Secplane, PointToDist, PointToDist)
 	ACTION_RETURN_FLOAT(self->PointToDist(DVector2(x, y), z));
 }
 
+//=====================================================================================
+//
+// FFont exports
+//
+//=====================================================================================
+
+static FFont *GetFont(int name)
+{
+	return V_GetFont(FName(ENamedName(name)).GetChars());
+}
+
+DEFINE_ACTION_FUNCTION_NATIVE(FFont, GetFont, GetFont)
+{
+	PARAM_PROLOGUE;
+	PARAM_INT(name);
+	ACTION_RETURN_POINTER(GetFont(name));
+}
+
+static FFont *FindFont(int name)
+{
+	return FFont::FindFont(FName(ENamedName(name)));
+}
+
+DEFINE_ACTION_FUNCTION_NATIVE(FFont, FindFont, FindFont)
+{
+	PARAM_PROLOGUE;
+	PARAM_NAME(name);
+	ACTION_RETURN_POINTER(FFont::FindFont(name));
+}
+
+static int GetCharWidth(FFont *font, int code)
+{
+	return font->GetCharWidth(code);
+}
+
+DEFINE_ACTION_FUNCTION_NATIVE(FFont, GetCharWidth, GetCharWidth)
+{
+	PARAM_SELF_STRUCT_PROLOGUE(FFont);
+	PARAM_INT(code);
+	ACTION_RETURN_INT(self->GetCharWidth(code));
+}
+
+static int GetHeight(FFont *font)
+{
+	return font->GetHeight();
+}
+
+DEFINE_ACTION_FUNCTION_NATIVE(FFont, GetHeight, GetHeight)
+{
+	PARAM_SELF_STRUCT_PROLOGUE(FFont);
+	ACTION_RETURN_INT(self->GetHeight());
+}
+
+double GetBottomAlignOffset(FFont *font, int c);
+DEFINE_ACTION_FUNCTION_NATIVE(FFont, GetBottomAlignOffset, GetBottomAlignOffset)
+{
+	PARAM_SELF_STRUCT_PROLOGUE(FFont);
+	PARAM_INT(code);
+	ACTION_RETURN_FLOAT(GetBottomAlignOffset(self, code));
+}
+
+static int StringWidth(FFont *font, const FString &str)
+{
+	const char *txt = str[0] == '$' ? GStrings(&str[1]) : str.GetChars();
+	return font->StringWidth(txt);
+}
+
+DEFINE_ACTION_FUNCTION_NATIVE(FFont, StringWidth, StringWidth)
+{
+	PARAM_SELF_STRUCT_PROLOGUE(FFont);
+	PARAM_STRING(str);
+	ACTION_RETURN_INT(StringWidth(self, str));
+}
+
+DEFINE_ACTION_FUNCTION_NATIVE(FFont, FindFontColor, V_FindFontColor)
+{
+	PARAM_PROLOGUE;
+	PARAM_NAME(code);
+	ACTION_RETURN_INT((int)V_FindFontColor(code));
+}
+
+static void GetCursor(FFont *font, FString *result)
+{
+	*result = font->GetCursor();
+}
+
+DEFINE_ACTION_FUNCTION_NATIVE(FFont, GetCursor, GetCursor)
+{
+	PARAM_SELF_STRUCT_PROLOGUE(FFont);
+	ACTION_RETURN_STRING(FString(self->GetCursor()));
+}
+
+//=====================================================================================
+//
+// AActor exports (this will be expanded)
+//
+//=====================================================================================
+
 DEFINE_ACTION_FUNCTION_NATIVE(AActor, A_PlaySound, A_PlaySound)
 {
 	PARAM_SELF_PROLOGUE(AActor);
diff --git a/src/v_font.cpp b/src/v_font.cpp
index 3a589e7413..eed94341b8 100644
--- a/src/v_font.cpp
+++ b/src/v_font.cpp
@@ -336,14 +336,6 @@ FFont *V_GetFont(const char *name)
 	return font;
 }
 
-DEFINE_ACTION_FUNCTION(FFont, GetFont)
-{
-	PARAM_PROLOGUE;
-	PARAM_NAME(name);
-	ACTION_RETURN_POINTER(V_GetFont(name.GetChars()));
-}
-
-
 //==========================================================================
 //
 // FFont :: FFont
@@ -528,13 +520,6 @@ FFont *FFont::FindFont (FName name)
 	return nullptr;
 }
 
-DEFINE_ACTION_FUNCTION(FFont, FindFont)
-{
-	PARAM_PROLOGUE;
-	PARAM_NAME(name);
-	ACTION_RETURN_POINTER(FFont::FindFont(name));
-}
-
 //==========================================================================
 //
 // RecordTextureColors
@@ -856,17 +841,21 @@ int FFont::GetCharWidth (int code) const
 	return (code < 0) ? SpaceWidth : Chars[code - FirstChar].XMove;
 }
 
-DEFINE_ACTION_FUNCTION(FFont, GetCharWidth)
-{
-	PARAM_SELF_STRUCT_PROLOGUE(FFont);
-	PARAM_INT(code);
-	ACTION_RETURN_INT(self->GetCharWidth(code));
-}
+//==========================================================================
+//
+// 
+//
+//==========================================================================
 
-DEFINE_ACTION_FUNCTION(FFont, GetHeight)
+double GetBottomAlignOffset(FFont *font, int c)
 {
-	PARAM_SELF_STRUCT_PROLOGUE(FFont);
-	ACTION_RETURN_INT(self->GetHeight());
+	int w;
+	FTexture *tex_zero = font->GetChar('0', &w);
+	FTexture *texc = font->GetChar(c, &w);
+	double offset = 0;
+	if (texc) offset += texc->GetScaledTopOffsetDouble(0);
+	if (tex_zero) offset += -tex_zero->GetScaledTopOffsetDouble(0) + tex_zero->GetScaledHeightDouble();
+	return offset;
 }
 
 //==========================================================================
@@ -914,15 +903,6 @@ int FFont::StringWidth(const uint8_t *string) const
 	return MAX(maxw, w);
 }
 
-DEFINE_ACTION_FUNCTION(FFont, StringWidth)
-{
-	PARAM_SELF_STRUCT_PROLOGUE(FFont);
-	PARAM_STRING(str);
-	const char *txt = str[0] == '$' ? GStrings(&str[1]) : str.GetChars();
-
-	ACTION_RETURN_INT(self->StringWidth(txt));
-}
-
 //==========================================================================
 //
 // FFont :: LoadTranslations
@@ -2540,13 +2520,6 @@ EColorRange V_FindFontColor (FName name)
 	return CR_UNTRANSLATED;
 }
 
-DEFINE_ACTION_FUNCTION(FFont, FindFontColor)
-{
-	PARAM_PROLOGUE;
-	PARAM_NAME(code);
-	ACTION_RETURN_INT((int)V_FindFontColor(code));
-}
-
 //==========================================================================
 //
 // V_LogColorFromColorRange
@@ -2721,8 +2694,3 @@ void V_ClearFonts()
 	SmallFont = SmallFont2 = BigFont = ConFont = IntermissionFont = NULL;
 }
 
-DEFINE_ACTION_FUNCTION(FFont, GetCursor)
-{
-	PARAM_SELF_STRUCT_PROLOGUE(FFont);
-	ACTION_RETURN_STRING(FString(self->GetCursor()));
-}
diff --git a/src/v_video.h b/src/v_video.h
index f54092509f..1cba846f02 100644
--- a/src/v_video.h
+++ b/src/v_video.h
@@ -218,7 +218,6 @@ enum
 	DTA_SrcHeight,
 	DTA_LegacyRenderStyle,	// takes an old-style STYLE_* constant instead of an FRenderStyle
 	DTA_Burn,				// activates the burn shader for this element
-
 };
 
 enum