Free Hero Mesh

  Value v;
  while(vstackptr-- && vstack[vstackptr].t!=TY_MARK);
  if(!vstackptr) Throw("No mark");
  v=Pop();
  while(--p>vstackptr) if(v_equal(v,vstack[p])) return 1;
  return 0;
}

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;
}

// 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_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_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_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;