Index: class.c
==================================================================
--- class.c
+++ class.c
@@ -1055,11 +1055,11 @@
         case OP_STRING:
           AddInst2(OP_STRING,pool_string(tokenstr));
           break;
         default:
           if(Tokenf(TF_ABNORMAL)) ParseError("Invalid instruction token\n");
-          if(compat && Tokenf(TF_COMPAT)) ++tokenv;
+          if(compat && Tokenf(TF_COMPAT) && Tokenf(TF_EQUAL)) ++tokenv;
           AddInstF(tokenv,tokent);
       }
     } else if(Tokenf(TF_FUNCTION)) {
       AddInst2(OP_FUNCTION,tokenv&0x3FFF);
     } else if(tokent==TF_OPEN) {

Index: exec.c
==================================================================
--- exec.c
+++ exec.c
@@ -156,17 +156,43 @@
   if(o->next) objects[o->next]->prev=o->prev;
   free(o);
   objects[n]=0;
   generation_number_inc=1;
 }
+
+static Uint32 obj_above(Uint32 i) {
+  Object*o;
+  if(i==VOIDLINK) return VOIDLINK;
+  o=objects[i];
+  i=o->up;
+  while(i!=VOIDLINK) {
+    o=objects[i];
+    if(!(o->oflags&(OF_DESTROYED|OF_VISUALONLY))) return i;
+    i=o->up;
+  }
+  return VOIDLINK;
+}
+
+static Uint32 obj_below(Uint32 i) {
+  Object*o;
+  if(i==VOIDLINK) return VOIDLINK;
+  o=objects[i];
+  i=o->down;
+  while(i!=VOIDLINK) {
+    o=objects[i];
+    if(!(o->oflags&(OF_DESTROYED|OF_VISUALONLY))) return i;
+    i=o->down;
+  }
+  return VOIDLINK;
+}
 
 static Uint32 obj_class_at(Uint32 c,Uint32 x,Uint32 y) {
   Uint32 i;
   if(x<1 || x>pfwidth || y<1 || y>pfheight) return VOIDLINK;
   i=playfield[x+y*64-65];
   while(i!=VOIDLINK) {
-    if(objects[i]->class==c && !(objects[i]->oflags&OF_DESTROYED) && !(objects[i]->dir&IOF_DEAD)) return i;
+    if(objects[i]->class==c && !(objects[i]->oflags&OF_DESTROYED)) return i;
     i=objects[i]->up;
   }
   return VOIDLINK;
 }
 
@@ -187,11 +213,11 @@
   return 0;
 }
 
 static Uint32 v_object(Value v) {
   if(v.t==TY_NUMBER) {
-    if(v.u) Throw("Cannot convert number to object");
+    if(v.u) Throw("Cannot convert non-zero number to object");
     return VOIDLINK;
   } else if(v.t>TY_MAXTYPE) {
     if(v.u>=nobjects || !objects[v.u]) Throw("Attempt to use a nonexistent object");
     if(objects[v.u]->generation!=v.t) Throw("Attempt to use a nonexistent object");
     return v.u;
@@ -257,11 +283,11 @@
 
 // Here is where the execution of a Free Hero Mesh bytecode subroutine is executed.
 #define NoIgnore() do{ changed=1; }while(0)
 #define GetVariableOf(a,b) (i=v_object(Pop()),i==VOIDLINK?NVALUE(0):b(objects[i]->a))
 #define Numeric(a) do{ if((a).t!=TY_NUMBER) Throw("Type mismatch"); }while(0)
-#define DivideBy(a) do { if(!(a).u) Throw("Division by zero"); }while(0)
+#define DivideBy(a) do{ if(!(a).u) Throw("Division by zero"); }while(0)
 static void execute_program(Uint16*code,int ptr,Uint32 obj) {
   Uint32 i;
   Object*o=objects[obj];
   Value t1,t2;
   static Value t3,t4,t5;
@@ -305,17 +331,22 @@
     case 0x3000 ... 0x37FF: NoIgnore(); StackReq(1,0); o->uservars[code[ptr-1]&0x7FF]=Pop(); break;
     case 0x3800 ... 0x38FF: NoIgnore(); StackReq(1,0); globals[code[ptr-1]&0x7FF]=Pop(); break;
     case 0x4000 ... 0x7FFF: StackReq(0,1); Push(CVALUE(code[ptr-1]-0x4000)); break;
     case 0x87E8 ... 0x87FF: StackReq(0,1); Push(NVALUE(1UL<<(code[ptr-1]&31))); break;
     case 0xC000 ... 0xFFFF: StackReq(0,1); Push(MVALUE((code[ptr-1]&0x3FFF)+256)); break;
+    case OP_ADD: StackReq(2,1); t2=Pop(); Numeric(t2); t1=Pop(); Numeric(t1); Push(NVALUE(t1.u+t2.u)); break;
+    case OP_BAND: StackReq(2,1); t2=Pop(); Numeric(t2); t1=Pop(); Numeric(t1); Push(NVALUE(t1.u&t2.u)); break;
+    case OP_BNOT: StackReq(1,1); t1=Pop(); Numeric(t1); Push(NVALUE(~t1.u)); break;
+    case OP_BOR: StackReq(2,1); t2=Pop(); Numeric(t2); t1=Pop(); Numeric(t1); Push(NVALUE(t1.u|t2.u)); break;
     case OP_BROADCAST: StackReq(4,1); t4=Pop(); t3=Pop(); t2=Pop(); t1=Pop(); Push(v_broadcast(obj,t1,t2,t3,t4,NVALUE(0),0)); break;
     case OP_BROADCAST_D: StackReq(4,0); t4=Pop(); t3=Pop(); t2=Pop(); t1=Pop(); v_broadcast(obj,t1,t2,t3,t4,NVALUE(0),0); break;
     case OP_BROADCASTCLASS: StackReq(3,1); t4=Pop(); t3=Pop(); t2=Pop(); Push(v_broadcast(obj,CVALUE(code[ptr++]),t2,t3,t4,NVALUE(0),0)); break;
     case OP_BROADCASTEX: StackReq(5,1); t5=Pop(); t4=Pop(); t3=Pop(); t2=Pop(); t1=Pop(); Push(v_broadcast(obj,t1,t2,t3,t4,t5,0)); break;
     case OP_BROADCASTEX_D: StackReq(5,0); t5=Pop(); t4=Pop(); t3=Pop(); t2=Pop(); t1=Pop(); v_broadcast(obj,t1,t2,t3,t4,t5,0); break;
     case OP_BROADCASTSUM: StackReq(4,1); t4=Pop(); t3=Pop(); t2=Pop(); t1=Pop(); Push(v_broadcast(obj,t1,t2,t3,t4,NVALUE(0),1)); break;
     case OP_BROADCASTSUMEX: StackReq(5,1); t5=Pop(); t4=Pop(); t3=Pop(); t2=Pop(); t1=Pop(); Push(v_broadcast(obj,t1,t2,t3,t4,t5,1)); break;
+    case OP_BXOR: StackReq(2,1); t2=Pop(); Numeric(t2); t1=Pop(); Numeric(t1); Push(NVALUE(t1.u^t2.u)); break;
     case OP_CALLSUB: execute_program(code,code[ptr++],obj); break;
     case OP_CLASS: StackReq(0,1); Push(CVALUE(o->class)); break;
     case OP_CLASS_C: StackReq(1,1); Push(GetVariableOf(class,CVALUE)); break;
     case OP_DIR: StackReq(0,1); Push(NVALUE(o->dir&7)); break;
     case OP_DISTANCE: StackReq(0,1); Push(NVALUE(o->distance)); break;
@@ -340,12 +371,17 @@
     case OP_LOC: StackReq(0,2); Push(NVALUE(o->x)); Push(NVALUE(o->y)); break;
     case OP_LOR: StackReq(2,1); t1=Pop(); t2=Pop(); if(v_bool(t1) || v_bool(t2)) Push(NVALUE(1)); else Push(NVALUE(0)); break;
     case OP_LOSELEVEL: gameover=-1; Throw(0); break;
     case OP_LT: StackReq(2,1); t2=Pop(); t1=Pop(); Push(NVALUE(v_unsigned_greater(t2,t1)?1:0)); break;
     case OP_LT_C: StackReq(2,1); t2=Pop(); t1=Pop(); Push(NVALUE(v_signed_greater(t2,t1)?1:0)); break;
+    case OP_LXOR: StackReq(2,1); t1=Pop(); t2=Pop(); if(v_bool(t1)?!v_bool(t2):v_bool(t2)) Push(NVALUE(1)); else Push(NVALUE(0)); break;
     case OP_NE: StackReq(2,1); t2=Pop(); t1=Pop(); Push(NVALUE(v_equal(t1,t2)?0:1)); break;
     case OP_NIP: StackReq(2,1); t1=Pop(); Pop(); Push(t1); break;
+    case OP_OBJABOVE: StackReq(0,1); i=obj_above(obj); Push(OVALUE(i)); break;
+    case OP_OBJABOVE_C: StackReq(1,1); i=obj_above(v_object(Pop())); Push(OVALUE(i)); break;
+    case OP_OBJBELOW: StackReq(0,1); i=obj_below(obj); Push(OVALUE(i)); break;
+    case OP_OBJBELOW_C: StackReq(1,1); i=obj_below(v_object(Pop())); Push(OVALUE(i)); break;
     case OP_OBJCLASSAT: StackReq(3,1); t3=Pop(); t2=Pop(); t1=Pop(); Push(v_obj_class_at(t1,t2,t3)); break;
     case OP_RET: return;
     case OP_SEND: StackReq(3,1); t4=Pop(); t3=Pop(); t2=Pop(); Push(v_send_self(obj,t2,t3,t4,NVALUE(0))); break;
     case OP_SEND_C: StackReq(4,1); t4=Pop(); t3=Pop(); t2=Pop(); t1=Pop(); Push(v_send_message(obj,t1,t2,t3,t4,NVALUE(0))); break;
     case OP_SEND_D: StackReq(3,0); t4=Pop(); t3=Pop(); t2=Pop(); v_send_self(obj,t2,t3,t4,NVALUE(0)); break;
@@ -353,15 +389,26 @@
     case OP_SENDEX: StackReq(4,1); t5=Pop(); t4=Pop(); t3=Pop(); t2=Pop(); Push(v_send_self(obj,t2,t3,t4,t5)); break;
     case OP_SENDEX_C: StackReq(5,1); t5=Pop(); t4=Pop(); t3=Pop(); t2=Pop(); t1=Pop(); Push(v_send_message(obj,t1,t2,t3,t4,t5)); break;
     case OP_SENDEX_D: StackReq(4,0); t5=Pop(); t4=Pop(); t3=Pop(); t2=Pop(); v_send_self(obj,t2,t3,t4,t5); break;
     case OP_SENDEX_CD: StackReq(5,0); t5=Pop(); t4=Pop(); t3=Pop(); t2=Pop(); t1=Pop(); v_send_message(obj,t1,t2,t3,t4,t5); break;
     case OP_SOUND: StackReq(2,0); t2=Pop(); t1=Pop(); break; // Sound not implemented at this time
+    case OP_SUB: StackReq(2,1); t2=Pop(); Numeric(t2); t1=Pop(); Numeric(t1); Push(NVALUE(t1.u-t2.u)); break;
     case OP_SWAP: StackReq(2,2); t1=Pop(); t2=Pop(); Push(t1); Push(t2); break;
     case OP_TRACE: StackReq(3,0); trace_stack(obj); break;
     case OP_WINLEVEL: key_ignored=0; gameover=1; Throw(0); break;
     case OP_XLOC: StackReq(0,1); Push(NVALUE(o->x)); break;
     case OP_YLOC: StackReq(0,1); Push(NVALUE(o->y)); break;
+#define MiscVar(a,b) \
+    case a: StackReq(0,1); Push(o->b); break; \
+    case a+0x0800: StackReq(1,1); Push(GetVariableOf(b,)); break; \
+    case a+0x1000: StackReq(1,0); objects[i]->b=Pop(); break; \
+    case a+0x1001: StackReq(1,0); t1=Pop(); if(!t1.t) t1.u&=0xFFFF; objects[i]->b=t1; break; \
+    case a+0x1800: StackReq(2,0); t1=Pop(); i=v_object(Pop()); if(i!=VOIDLINK) objects[i]->b=t1; break; \
+    case a+0x1801: StackReq(2,0); t1=Pop(); if(!t1.t) t1.u&=0xFFFF; i=v_object(Pop()); if(i!=VOIDLINK) objects[i]->b=t1; break;
+    MiscVar(OP_MISC1,misc1) MiscVar(OP_MISC2,misc2) MiscVar(OP_MISC3,misc3)
+    MiscVar(OP_MISC4,misc4) MiscVar(OP_MISC5,misc5) MiscVar(OP_MISC6,misc6) MiscVar(OP_MISC7,misc7)
+#undef MiscVar
     default: fprintf(stderr,"Unrecognized opcode 0x%04X at 0x%04X in $%s\n",code[ptr-1],ptr-1,classes[o->class]->name); Throw("Internal error: Unrecognized opcode");
   }
 }
 
 static void trace_message(Uint32 obj) {

Index: heromesh.h
==================================================================
--- heromesh.h
+++ heromesh.h
@@ -169,11 +169,11 @@
 #define VOIDLINK ((Uint32)(-1))
 
 // The following "internal object flags" are part of the "dir" variable:
 #define IOF_DEAD 0x10 // object doesn't exist, except to continue an animation
 #define IOF_ANIM 0x20 // an animation is being displayed
-// If the IOF_DEAD flag is set, then generation should also be set to zero.
+// If the IOF_DEAD flag is set, then generation should also be set to zero, and OF_DESTROYED must be set, too.
 
 typedef struct {
   Sint32 height,weight,climb,density,volume,strength,arrivals,departures,temperature;
   Uint32 arrived,departed,arrived2,departed2,generation;
   Uint32 up,down,prev,next; // links to other objects

Index: instruc.h
==================================================================
--- instruc.h
+++ instruc.h
@@ -62,11 +62,11 @@
 #define OP_CLASS_C 34859
 #define OP_TEMPERATURE 32812
 #define OP_TEMPERATURE_C 34860
 #define OP_TEMPERATURE_E 36908
 #define OP_TEMPERATURE_EC 38956
-#define OP_TEMPERATURE_EC16 34861
+#define OP_TEMPERATURE_EC16 38957
 #define OP_TEMPERATURE_E16 36909
 #define OP_SHAPE 32814
 #define OP_SHAPE_C 34862
 #define OP_SHAPE_E 36910
 #define OP_SHAPE_EC 38958
@@ -84,53 +84,53 @@
 #define OP_IMAGE_EC 38962
 #define OP_INERTIA 32819
 #define OP_INERTIA_C 34867
 #define OP_INERTIA_E 36915
 #define OP_INERTIA_EC 38963
-#define OP_INERTIA_EC16 34868
+#define OP_INERTIA_EC16 38964
 #define OP_INERTIA_E16 36916
 #define OP_DISTANCE 32821
 #define OP_DISTANCE_C 34869
 #define OP_DISTANCE_E 36917
 #define OP_DISTANCE_EC 38965
-#define OP_DISTANCE_EC16 34870
+#define OP_DISTANCE_EC16 38966
 #define OP_DISTANCE_E16 36918
 #define OP_DENSITY 32823
 #define OP_DENSITY_C 34871
 #define OP_DENSITY_E 36919
 #define OP_DENSITY_EC 38967
-#define OP_DENSITY_EC16 34872
+#define OP_DENSITY_EC16 38968
 #define OP_DENSITY_E16 36920
 #define OP_VOLUME 32825
 #define OP_VOLUME_C 34873
 #define OP_VOLUME_E 36921
 #define OP_VOLUME_EC 38969
-#define OP_VOLUME_EC16 34874
+#define OP_VOLUME_EC16 38970
 #define OP_VOLUME_E16 36922
 #define OP_WEIGHT 32827
 #define OP_WEIGHT_C 34875
 #define OP_WEIGHT_E 36923
 #define OP_WEIGHT_EC 38971
-#define OP_WEIGHT_EC16 34876
+#define OP_WEIGHT_EC16 38972
 #define OP_WEIGHT_E16 36924
 #define OP_HEIGHT 32829
 #define OP_HEIGHT_C 34877
 #define OP_HEIGHT_E 36925
 #define OP_HEIGHT_EC 38973
-#define OP_HEIGHT_EC16 34878
+#define OP_HEIGHT_EC16 38974
 #define OP_HEIGHT_E16 36926
 #define OP_CLIMB 32831
 #define OP_CLIMB_C 34879
 #define OP_CLIMB_E 36927
 #define OP_CLIMB_EC 38975
-#define OP_CLIMB_EC16 34880
+#define OP_CLIMB_EC16 38976
 #define OP_CLIMB_E16 36928
 #define OP_STRENGTH 32833
 #define OP_STRENGTH_C 34881
 #define OP_STRENGTH_E 36929
 #define OP_STRENGTH_EC 38977
-#define OP_STRENGTH_EC16 34882
+#define OP_STRENGTH_EC16 38978
 #define OP_STRENGTH_E16 36930
 #define OP_HARD 32835
 #define OP_HARD_C 34883
 #define OP_HARD_E 36931
 #define OP_HARD_EC 38979
@@ -148,47 +148,47 @@
 #define OP_SHOVABLE_EC 38982
 #define OP_MISC1 32839
 #define OP_MISC1_C 34887
 #define OP_MISC1_E 36935
 #define OP_MISC1_EC 38983
-#define OP_MISC1_EC16 34888
+#define OP_MISC1_EC16 38984
 #define OP_MISC1_E16 36936
 #define OP_MISC2 32841
 #define OP_MISC2_C 34889
 #define OP_MISC2_E 36937
 #define OP_MISC2_EC 38985
-#define OP_MISC2_EC16 34890
+#define OP_MISC2_EC16 38986
 #define OP_MISC2_E16 36938
 #define OP_MISC3 32843
 #define OP_MISC3_C 34891
 #define OP_MISC3_E 36939
 #define OP_MISC3_EC 38987
-#define OP_MISC3_EC16 34892
+#define OP_MISC3_EC16 38988
 #define OP_MISC3_E16 36940
 #define OP_MISC4 32845
 #define OP_MISC4_C 34893
 #define OP_MISC4_E 36941
 #define OP_MISC4_EC 38989
-#define OP_MISC4_EC16 34894
+#define OP_MISC4_EC16 38990
 #define OP_MISC4_E16 36942
 #define OP_MISC5 32847
 #define OP_MISC5_C 34895
 #define OP_MISC5_E 36943
 #define OP_MISC5_EC 38991
-#define OP_MISC5_EC16 34896
+#define OP_MISC5_EC16 38992
 #define OP_MISC5_E16 36944
 #define OP_MISC6 32849
 #define OP_MISC6_C 34897
 #define OP_MISC6_E 36945
 #define OP_MISC6_EC 38993
-#define OP_MISC6_EC16 34898
+#define OP_MISC6_EC16 38994
 #define OP_MISC6_E16 36946
 #define OP_MISC7 32851
 #define OP_MISC7_C 34899
 #define OP_MISC7_E 36947
 #define OP_MISC7_EC 38995
-#define OP_MISC7_EC16 34900
+#define OP_MISC7_EC16 38996
 #define OP_MISC7_E16 36948
 #define OP_ARRIVED 32853
 #define OP_ARRIVED_C 34901
 #define OP_ARRIVED_E 36949
 #define OP_ARRIVED_EC 38997

Index: instruc.js
==================================================================
--- instruc.js
+++ instruc.js
@@ -37,11 +37,11 @@
     console.log("#define OP_"+reg[2].toUpperCase()+" "+curnum);
     if(flags&1) console.log("#define OP_"+reg[2].toUpperCase()+"_C "+(curnum+0x0800));
     if(flags&2) console.log("#define OP_"+reg[2].toUpperCase()+"_E "+(curnum+0x1000));
     if(3==(flags&3)) console.log("#define OP_"+reg[2].toUpperCase()+"_EC "+(curnum+0x1800));
     if(10==(flags&10)) {
-      if(flags&1) console.log("#define OP_"+reg[2].toUpperCase()+"_EC16 "+(curnum+0x0801));
+      if(flags&1) console.log("#define OP_"+reg[2].toUpperCase()+"_EC16 "+(curnum+0x1801));
       console.log("#define OP_"+reg[2].toUpperCase()+"_E16 "+(curnum+0x1001));
     }
     if(flags&32) {
       console.log("#define OP_"+reg[2].toUpperCase()+"_D "+(curnum+0x2000));
       if(flags&1) console.log("#define OP_"+reg[2].toUpperCase()+"_CD "+(curnum+0x2800));