Free Hero Mesh

  while(i!=VOIDLINK) {
    o=objects[i];
    if(r<o->volume && !(o->oflags&(OF_DESTROYED|OF_VISUALONLY))) r=o->volume;
    i=o->up;
  }
  return r;
}

static Uint32 obj_seek(Uint32 aa,Uint32 bb) {
  Object*a;
  Object*b;
  if(aa==VOIDLINK || bb==VOIDLINK) Throw("Cannot seek to zero object");
  a=objects[aa]; b=objects[bb];
  if(a->x==b->x) {
    if(a->y==b->y) return 8;
    return a->y<b->y?6:2;
  } else if(a->x<b->x) {
    if(a->y==b->y) return 0;
    return a->y<b->y?7:1;
  } else {
    if(a->y==b->y) return 4;
    return a->y<b->y?5:3;
  }
}

static Uint32 obj_above(Uint32 i) {
  Object*o;
  if(i==VOIDLINK) return VOIDLINK;
  o=objects[i];
  i=o->up;
  while(i!=VOIDLINK) {

static Uint32 v_chain(Value v,Uint16 c) {
  if(v.t==TY_SOUND || v.t==TY_USOUND) Throw("Cannot convert sound to object");
  if(v.t<=TY_MAXTYPE) return VOIDLINK;
  if(v.u>=nobjects || !objects[v.u] || objects[v.u]->generation!=v.t) return VOIDLINK;
  if(objects[v.u]->class!=c) return VOIDLINK;
  return v.u;
}

static inline Uint32 manhattan(Uint32 a,Uint32 b) {
  if(a==VOIDLINK || b==VOIDLINK) return 0;
  return abs(objects[a]->x-objects[b]->x)+abs(objects[a]->y-objects[b]->y);
}

static inline Uint32 chebyshev(Uint32 a,Uint32 b) {
  Uint32 i,j;
  if(a==VOIDLINK || b==VOIDLINK) return 0;
  i=abs(objects[a]->x-objects[b]->x);
  j=abs(objects[a]->y-objects[b]->y);
  return i>j?i:j;
}

// 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 GetVariableOrAttributeOf(a,b) (t2=Pop(),t2.t==TY_CLASS?NVALUE(classes[t2.u]->a):(i=v_object(t2),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{ Numeric(a); if(!(a).u) Throw("Division by zero"); }while(0)

    case OP_BUSY: StackReq(0,1); if(o->oflags&OF_BUSY) Push(NVALUE(1)); else Push(NVALUE(0)); break;
    case OP_BUSY_C: StackReq(1,1); GetFlagOf(OF_BUSY); break;
    case OP_BUSY_E: NoIgnore(); StackReq(1,0); if(v_bool(Pop())) o->oflags|=OF_BUSY; else o->oflags&=~OF_BUSY; break;
    case OP_BUSY_EC: NoIgnore(); StackReq(2,0); SetFlagOf(OF_BUSY); 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_CHAIN: StackReq(1,1); t1=Pop(); i=v_chain(t1,o->class); if(i==VOIDLINK) { Push(NVALUE(1)); } else { o=objects[obj=i]; Push(NVALUE(0)); } break;
    case OP_CHEBYSHEV: StackReq(1,1); t1=Pop(); i=chebyshev(obj,v_object(t1)); Push(NVALUE(i)); break;
    case OP_CHEBYSHEV_C: StackReq(2,1); t2=Pop(); t1=Pop(); i=chebyshev(v_object(t1),v_object(t2)); Push(NVALUE(i)); 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_CLIMB: StackReq(0,1); Push(NVALUE(o->climb)); break;
    case OP_CLIMB_C: StackReq(1,1); Push(GetVariableOrAttributeOf(climb,NVALUE)); break;
    case OP_CLIMB_E: NoIgnore(); StackReq(1,0); t1=Pop(); Numeric(t1); o->climb=t1.u; break;
    case OP_CLIMB_E16: NoIgnore(); StackReq(1,0); t1=Pop(); Numeric(t1); o->climb=t1.u&0xFFFF; break;
    case OP_CLIMB_EC: NoIgnore(); StackReq(2,0); t1=Pop(); Numeric(t1); i=v_object(Pop()); if(i!=VOIDLINK) o->climb=t1.u; break;

    case OP_LOCATEME: locate_me(o->x,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_LSH: StackReq(2,1); t2=Pop(); Numeric(t2); t1=Pop(); Numeric(t1); Push(NVALUE(t2.u&~31?0:t1.u<<t2.u)); 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_MANHATTAN: StackReq(1,1); t1=Pop(); i=manhattan(obj,v_object(t1)); Push(NVALUE(i)); break;
    case OP_MANHATTAN_C: StackReq(2,1); t2=Pop(); t1=Pop(); i=manhattan(v_object(t1),v_object(t2)); Push(NVALUE(i)); break;
    case OP_MARK: StackReq(0,1); Push(UVALUE(0,TY_MARK)); break;
    case OP_MAXINVENTORY: StackReq(1,0); t1=Pop(); Numeric(t1); if(ninventory>t1.u) Throw("Inventory overflow"); break;
    case OP_MOD: StackReq(2,1); t2=Pop(); DivideBy(t2); t1=Pop(); Numeric(t1); Push(NVALUE(t1.u%t2.u)); break;
    case OP_MOD_C: StackReq(2,1); t2=Pop(); DivideBy(t2); t1=Pop(); Numeric(t1); Push(NVALUE(t1.s%t2.s)); break;
    case OP_MOVE: NoIgnore(); StackReq(1,1); t1=Pop(); Numeric(t1); o->inertia=o->strength; Push(NVALUE(move_dir(obj,obj,t1.u))); break;
    case OP_MOVE_C: NoIgnore(); StackReq(2,1); t1=Pop(); Numeric(t1); i=v_object(Pop()); if(i==VOIDLINK) Push(NVALUE(0)); else { objects[i]->inertia=o->strength; Push(NVALUE(move_dir(obj,i,t1.u))); } break;
    case OP_MOVE_D: NoIgnore(); StackReq(1,0); t1=Pop(); Numeric(t1); o->inertia=o->strength; move_dir(obj,obj,t1.u); break;

    case OP_QC: StackReq(1,1); t1=Pop(); NotSound(t1); if(t1.t==TY_CLASS) Push(NVALUE(1)); else Push(NVALUE(0)); break;
    case OP_QCZ: StackReq(1,1); t1=Pop(); NotSound(t1); if(t1.t==TY_CLASS || (t1.t==TY_NUMBER && !t1.u)) Push(NVALUE(1)); else Push(NVALUE(0)); break;
    case OP_QM: StackReq(1,1); t1=Pop(); NotSound(t1); if(t1.t==TY_MESSAGE) Push(NVALUE(1)); else Push(NVALUE(0)); break;
    case OP_QN: StackReq(1,1); t1=Pop(); NotSound(t1); if(t1.t==TY_NUMBER) Push(NVALUE(1)); else Push(NVALUE(0)); break;
    case OP_QO: StackReq(1,1); t1=Pop(); NotSound(t1); if(t1.t>TY_MAXTYPE) Push(NVALUE(1)); else Push(NVALUE(0)); break;
    case OP_QOZ: StackReq(1,1); t1=Pop(); NotSound(t1); if(t1.t>TY_MAXTYPE || (t1.t==TY_NUMBER && !t1.u)) Push(NVALUE(1)); else Push(NVALUE(0)); break;
    case OP_QS: StackReq(1,1); t1=Pop(); NotSound(t1); if(t1.t==TY_STRING || t1.t==TY_LEVELSTRING) Push(NVALUE(1)); else Push(NVALUE(0)); break;
    case OP_REL: StackReq(1,1); t1=Pop(); Numeric(t1); i=resolve_dir(obj,t1.u); Push(NVALUE(i)); break;
    case OP_REL_C: StackReq(2,1); t2=Pop(); Numeric(t2); t1=Pop(); i=v_object(t1); i=(i==VOIDLINK?t2.u:resolve_dir(i,t2.u)); Push(NVALUE(i)); break;
    case OP_RET: return;
    case OP_ROT: StackReq(3,3); t3=Pop(); t2=Pop(); t1=Pop(); Push(t2); Push(t3); Push(t1); break;
    case OP_ROTBACK: StackReq(3,3); t3=Pop(); t2=Pop(); t1=Pop(); Push(t3); Push(t1); Push(t2); break;
    case OP_RSH: StackReq(2,1); t2=Pop(); Numeric(t2); t1=Pop(); Numeric(t1); Push(NVALUE(t2.u&~31?0:t1.u>>t2.u)); break;
    case OP_RSH_C: StackReq(2,1); t2=Pop(); Numeric(t2); t1=Pop(); Numeric(t1); Push(NVALUE(t2.u&~31?(t1.s<0?-1:0):t1.s>>t2.u)); break;
    case OP_SEEK: StackReq(1,1); t1=Pop(); i=obj_seek(obj,v_object(t1)); Push(NVALUE(i)); break;
    case OP_SEEK_C: StackReq(2,1); t2=Pop(); t1=Pop(); i=obj_seek(v_object(t1),v_object(t2)); Push(NVALUE(i)); break;
    case OP_SELF: StackReq(0,1); Push(OVALUE(obj)); break;
    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;
    case OP_SEND_CD: StackReq(4,0); t4=Pop(); t3=Pop(); t2=Pop(); t1=Pop(); v_send_message(obj,t1,t2,t3,t4,NVALUE(0)); break;
    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;