sqvm.cpp

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/*
    see copyright notice in squirrel.h
*/
#include "sqpcheader.h"
#include <math.h>
#include <stdlib.h>
#include "sqopcodes.h"
#include "sqfuncproto.h"
#include "sqvm.h"
#include "sqclosure.h"
#include "sqstring.h"
#include "sqtable.h"
#include "squserdata.h"
#include "sqarray.h"
#include "sqclass.h"

#define TOP() (_stack._vals[_top-1])

#define CLEARSTACK(_last_top) { if((_last_top) >= _top) ClearStack(_last_top); }
void SQVM::ClearStack(SQInteger last_top)
{
    SQObjectType tOldType;
    SQObjectValue unOldVal;
    while (last_top >= _top) {
        SQObjectPtr &o = _stack._vals[last_top--];
        tOldType = o._type;
        unOldVal = o._unVal;
        o._type = OT_NULL;
        o._unVal.pUserPointer = NULL;
        __Release(tOldType,unOldVal);
    }
}

bool SQVM::BW_OP(SQUnsignedInteger op,SQObjectPtr &trg,const SQObjectPtr &o1,const SQObjectPtr &o2)
{
    SQInteger res;
    SQInteger i1 = _integer(o1), i2 = _integer(o2);
    if((type(o1)==OT_INTEGER) && (type(o2)==OT_INTEGER))
    {
        switch(op) {
            case BW_AND:    res = i1 & i2; break;
            case BW_OR:     res = i1 | i2; break;
            case BW_XOR:    res = i1 ^ i2; break;
            case BW_SHIFTL: res = i1 << i2; break;
            case BW_SHIFTR: res = i1 >> i2; break;
            case BW_USHIFTR:res = (SQInteger)(*((SQUnsignedInteger*)&i1) >> i2); break;
            default: { Raise_Error(_SC("internal vm error bitwise op failed")); return false; }
        }
    }
    else { Raise_Error(_SC("bitwise op between '%s' and '%s'"),GetTypeName(o1),GetTypeName(o2)); return false;}
    trg = res;
    return true;
}

bool SQVM::ARITH_OP(SQUnsignedInteger op,SQObjectPtr &trg,const SQObjectPtr &o1,const SQObjectPtr &o2)
{
    if(sq_isnumeric(o1) && sq_isnumeric(o2)) {
            if((type(o1)==OT_INTEGER) && (type(o2)==OT_INTEGER)) {
                SQInteger res, i1 = _integer(o1), i2 = _integer(o2);
                switch(op) {
                case '+': res = i1 + i2; break;
                case '-': res = i1 - i2; break;
                case '/': if(i2 == 0) { Raise_Error(_SC("division by zero")); return false; }
                    res = i1 / i2;
                    break;
                case '*': res = i1 * i2; break;
                case '%': if(i2 == 0) { Raise_Error(_SC("modulo by zero")); return false; }
                    res = i1 % i2;
                    break;
                default: res = 0xDEADBEEF;
                }
                trg = res;
            }else{
                SQFloat res, f1 = tofloat(o1), f2 = tofloat(o2);
                switch(op) {
                case '+': res = f1 + f2; break;
                case '-': res = f1 - f2; break;
                case '/': res = f1 / f2; break;
                case '*': res = f1 * f2; break;
                case '%': res = SQFloat(fmod((double)f1,(double)f2)); break;
                default: res = 0x0f;
                }
                trg = res;
            }
        } else {
            if(op == '+' && (type(o1) == OT_STRING || type(o2) == OT_STRING)){
                    if(!StringCat(o1, o2, trg)) return false;
            }
            else if(!ArithMetaMethod(op,o1,o2,trg)) {
                Raise_Error(_SC("arith op %c on between '%s' and '%s'"),op,GetTypeName(o1),GetTypeName(o2)); return false;
            }
        }
        return true;
}

SQVM::SQVM(SQSharedState *ss)
{
    _sharedstate=ss;
    _suspended = SQFalse;
    _suspended_target=-1;
    _suspended_root = SQFalse;
    _suspended_traps=-1;
    _foreignptr=NULL;
    _nnativecalls=0;
    _lasterror = _null_;
    _errorhandler = _null_;
    _debughook = _null_;
    ci = NULL;
    INIT_CHAIN();ADD_TO_CHAIN(&_ss(this)->_gc_chain,this);
}

void SQVM::Finalize()
{
    _roottable = _null_;
    _lasterror = _null_;
    _errorhandler = _null_;
    _debughook = _null_;
    temp_reg = _null_;
    _callstackdata.resize(0);
    SQInteger size=_stack.size();
    for(SQInteger i=0;i<size;i++)
        _stack[i]=_null_;
}

SQVM::~SQVM()
{
    Finalize();
    //sq_free(_callsstack,_alloccallsstacksize*sizeof(CallInfo));
    REMOVE_FROM_CHAIN(&_ss(this)->_gc_chain,this);
}

bool SQVM::ArithMetaMethod(SQInteger op,const SQObjectPtr &o1,const SQObjectPtr &o2,SQObjectPtr &dest)
{
    SQMetaMethod mm;
    switch(op){
        case _SC('+'): mm=MT_ADD; break;
        case _SC('-'): mm=MT_SUB; break;
        case _SC('/'): mm=MT_DIV; break;
        case _SC('*'): mm=MT_MUL; break;
        case _SC('%'): mm=MT_MODULO; break;
        default: mm = MT_ADD; assert(0); break; //shutup compiler
    }
    if(is_delegable(o1) && _delegable(o1)->_delegate) {
        Push(o1);Push(o2);
        return CallMetaMethod(_delegable(o1),mm,2,dest);
    }
    return false;
}

bool SQVM::NEG_OP(SQObjectPtr &trg,const SQObjectPtr &o)
{

    switch(type(o)) {
    case OT_INTEGER:
        trg = -_integer(o);
        return true;
    case OT_FLOAT:
        trg = -_float(o);
        return true;
    case OT_TABLE:
    case OT_USERDATA:
    case OT_INSTANCE:
        if(_delegable(o)->_delegate) {
            Push(o);
            if(CallMetaMethod(_delegable(o), MT_UNM, 1, temp_reg)) {
                trg = temp_reg;
                return true;
            }
        }
    default:break; //shutup compiler
    }
    Raise_Error(_SC("attempt to negate a %s"), GetTypeName(o));
    return false;
}

#define _RET_SUCCEED(exp) { result = (exp); return true; }
bool SQVM::ObjCmp(const SQObjectPtr &o1,const SQObjectPtr &o2,SQInteger &result)
{
    if(type(o1)==type(o2)){
        if(_rawval(o1)==_rawval(o2))_RET_SUCCEED(0);
        SQObjectPtr res;
        switch(type(o1)){
        case OT_STRING:
            _RET_SUCCEED(scstrcmp(_stringval(o1),_stringval(o2)));
        case OT_INTEGER:
            _RET_SUCCEED(_integer(o1)-_integer(o2));
        case OT_FLOAT:
            _RET_SUCCEED((_float(o1)<_float(o2))?-1:1);
        case OT_TABLE:
        case OT_USERDATA:
        case OT_INSTANCE:
            if(_delegable(o1)->_delegate) {
                Push(o1);Push(o2);
                if(CallMetaMethod(_delegable(o1),MT_CMP,2,res)) break;
            }
            //continues through (no break needed)
        default:
            _RET_SUCCEED( _userpointer(o1) < _userpointer(o2)?-1:1 );
        }
        if(type(res)!=OT_INTEGER) { Raise_CompareError(o1,o2); return false; }
            _RET_SUCCEED(_integer(res));

    }
    else{
        if(sq_isnumeric(o1) && sq_isnumeric(o2)){
            if((type(o1)==OT_INTEGER) && (type(o2)==OT_FLOAT)) {
                if( _integer(o1)==_float(o2) ) { _RET_SUCCEED(0); }
                else if( _integer(o1)<_float(o2) ) { _RET_SUCCEED(-1); }
                _RET_SUCCEED(1);
            }
            else{
                if( _float(o1)==_integer(o2) ) { _RET_SUCCEED(0); }
                else if( _float(o1)<_integer(o2) ) { _RET_SUCCEED(-1); }
                _RET_SUCCEED(1);
            }
        }
        else if(type(o1)==OT_NULL) {_RET_SUCCEED(-1);}
        else if(type(o2)==OT_NULL) {_RET_SUCCEED(1);}
        else { Raise_CompareError(o1,o2); return false; }

    }
    assert(0);
    _RET_SUCCEED(0); //cannot happen
}

bool SQVM::CMP_OP(CmpOP op, const SQObjectPtr &o1,const SQObjectPtr &o2,SQObjectPtr &res)
{
    SQInteger r;
    if(ObjCmp(o1,o2,r)) {
        switch(op) {
            case CMP_G: res = (r > 0)?_true_:_false_; return true;
            case CMP_GE: res = (r >= 0)?_true_:_false_; return true;
            case CMP_L: res = (r < 0)?_true_:_false_; return true;
            case CMP_LE: res = (r <= 0)?_true_:_false_; return true;

        }
        assert(0);
    }
    return false;
}

void SQVM::ToString(const SQObjectPtr &o,SQObjectPtr &res)
{
    switch(type(o)) {
    case OT_STRING:
        res = o;
        return;
    case OT_FLOAT:
        scsprintf(_sp(rsl(NUMBER_MAX_CHAR+1)),_SC("%g"),_float(o));
        break;
    case OT_INTEGER:
        // C::B patch: Support for Windows 64 bit
        #if defined(_WIN64)
        scsprintf(_sp(rsl(NUMBER_MAX_CHAR+1)),_SC("%I64d"),_integer(o));
        // C::B patch: Support for Linux 64 bit
        #elif  defined(_SQ64)
        scsprintf(_sp(rsl(NUMBER_MAX_CHAR+1)),_SC("%ld"),_integer(o));
        #else
        scsprintf(_sp(rsl(NUMBER_MAX_CHAR+1)),_SC("%d"),_integer(o));
        #endif
        break;
    case OT_BOOL:
        scsprintf(_sp(rsl(6)),_integer(o)?_SC("true"):_SC("false"));
        break;
    case OT_TABLE:
    case OT_USERDATA:
    case OT_INSTANCE:
        if(_delegable(o)->_delegate) {
            Push(o);
            if(CallMetaMethod(_delegable(o),MT_TOSTRING,1,res)) {
                if(type(res) == OT_STRING)
                    return;
                //else keeps going to the default
            }
        }
    default:
        scsprintf(_sp(rsl(sizeof(void*)+20)),_SC("(%s : 0x%p)"),GetTypeName(o),(void*)_rawval(o));
    }
    res = SQString::Create(_ss(this),_spval);
}


bool SQVM::StringCat(const SQObjectPtr &str,const SQObjectPtr &obj,SQObjectPtr &dest)
{
    SQObjectPtr a, b;
    ToString(str, a);
    ToString(obj, b);
    SQInteger l = _string(a)->_len , ol = _string(b)->_len;
    SQChar *s = _sp(rsl(l + ol + 1));
    memcpy(s, _stringval(a), rsl(l));
    memcpy(s + l, _stringval(b), rsl(ol));
    dest = SQString::Create(_ss(this), _spval, l + ol);
    return true;
}

void SQVM::TypeOf(const SQObjectPtr &obj1,SQObjectPtr &dest)
{
    if(is_delegable(obj1) && _delegable(obj1)->_delegate) {
        Push(obj1);
        if(CallMetaMethod(_delegable(obj1),MT_TYPEOF,1,dest))
            return;
    }
    dest = SQString::Create(_ss(this),GetTypeName(obj1));
}

bool SQVM::Init(SQVM *friendvm, SQInteger stacksize)
{
    _stack.resize(stacksize);
    _alloccallsstacksize = 4;
    _callstackdata.resize(_alloccallsstacksize);
    _callsstacksize = 0;
    _callsstack = &_callstackdata[0];
    _stackbase = 0;
    _top = 0;
    if(!friendvm)
        _roottable = SQTable::Create(_ss(this), 0);
    else {
        _roottable = friendvm->_roottable;
        _errorhandler = friendvm->_errorhandler;
        _debughook = friendvm->_debughook;
    }

    sq_base_register(this);
    return true;
}

extern SQInstructionDesc g_InstrDesc[];

bool SQVM::StartCall(SQClosure *closure,SQInteger target,SQInteger args,SQInteger stackbase,bool tailcall)
{
    SQFunctionProto *func = _funcproto(closure->_function);

    const SQInteger paramssize = func->_nparameters;
    const SQInteger newtop = stackbase + func->_stacksize;
    SQInteger nargs = args;
    if (paramssize != nargs) {
        SQInteger ndef = func->_ndefaultparams;
        SQInteger diff;
        if(ndef && nargs < paramssize && (diff = paramssize - nargs) <= ndef) {
            for(SQInteger n = ndef - diff; n < ndef; n++) {
                _stack._vals[stackbase + (nargs++)] = closure->_defaultparams[n];
            }
        }
        else if(func->_varparams)
        {
            if (nargs < paramssize) {
                Raise_Error(_SC("wrong number of parameters"));
                return false;
            }
            for(SQInteger n = 0; n < nargs - paramssize; n++) {
                _vargsstack.push_back(_stack._vals[stackbase+paramssize+n]);
                _stack._vals[stackbase+paramssize+n] = _null_;
            }
        }
        else {
            Raise_Error(_SC("wrong number of parameters"));
            return false;
        }
    }

    if(type(closure->_env) == OT_WEAKREF) {
        _stack._vals[stackbase] = _weakref(closure->_env)->_obj;
    }

    if (!tailcall) {
        CallInfo lc;
        lc._generator = NULL;
        lc._etraps = 0;
        lc._prevstkbase = (SQInt32) ( stackbase - _stackbase );
        lc._target = (SQInt32) target;
        lc._prevtop = (SQInt32) (_top - _stackbase);
        lc._ncalls = 1;
        lc._root = SQFalse;
        PUSH_CALLINFO(this, lc);
    }
    else {
        ci->_ncalls++;
    }
    ci->_vargs.size = (SQInt32)(nargs - paramssize);
    ci->_vargs.base = (SQInt32)(_vargsstack.size()-(ci->_vargs.size));
    ci->_closure = closure;
    ci->_literals = func->_literals;
    ci->_ip = func->_instructions;
    //grows the stack if needed
    if (((SQUnsignedInteger)newtop + (func->_stacksize<<1)) > _stack.size()) {
        _stack.resize(_stack.size() + (func->_stacksize<<1));
    }

    _top = newtop;
    _stackbase = stackbase;
    if (type(_debughook) != OT_NULL && _rawval(_debughook) != _rawval(ci->_closure))
        CallDebugHook(_SC('c'));
    return true;
}

bool SQVM::Return(SQInteger _arg0, SQInteger _arg1, SQObjectPtr &retval)
{
    if (type(_debughook) != OT_NULL && _rawval(_debughook) != _rawval(ci->_closure))
        for(SQInteger i=0;i<ci->_ncalls;i++)
            CallDebugHook(_SC('r'));

    SQBool broot = ci->_root;
    SQInteger last_top = _top;
    SQInteger target = ci->_target;
    SQInteger oldstackbase = _stackbase;
    _stackbase -= ci->_prevstkbase;
    _top = _stackbase + ci->_prevtop;
    if(ci->_vargs.size) PopVarArgs(ci->_vargs);
    POP_CALLINFO(this);
    if (broot) {
        if (_arg0 != MAX_FUNC_STACKSIZE) retval = _stack._vals[oldstackbase+_arg1];
        else retval = _null_;
    }
    else {
        if(target != -1) { //-1 is when a class contructor ret value has to be ignored
            if (_arg0 != MAX_FUNC_STACKSIZE)
                STK(target) = _stack._vals[oldstackbase+_arg1];
            else
                STK(target) = _null_;
        }
    }

    CLEARSTACK(last_top);
    assert(oldstackbase >= _stackbase);
    return broot?true:false;
}

#define _RET_ON_FAIL(exp) { if(!exp) return false; }

bool SQVM::LOCAL_INC(SQInteger op,SQObjectPtr &target, SQObjectPtr &a, SQObjectPtr &incr)
{
    _RET_ON_FAIL(ARITH_OP( op , target, a, incr));
    a = target;
    return true;
}

bool SQVM::PLOCAL_INC(SQInteger op,SQObjectPtr &target, SQObjectPtr &a, SQObjectPtr &incr)
{
    SQObjectPtr trg;
    _RET_ON_FAIL(ARITH_OP( op , trg, a, incr));
    target = a;
    a = trg;
    return true;
}

bool SQVM::DerefInc(SQInteger op,SQObjectPtr &target, SQObjectPtr &self, SQObjectPtr &key, SQObjectPtr &incr, bool postfix)
{
    SQObjectPtr tmp, tself = self, tkey = key;
    if (!Get(tself, tkey, tmp, false, true)) { Raise_IdxError(tkey); return false; }
    _RET_ON_FAIL(ARITH_OP( op , target, tmp, incr))
    Set(tself, tkey, target,true);
    if (postfix) target = tmp;
    return true;
}

#define arg0 (_i_._arg0)
#define arg1 (_i_._arg1)
#define sarg1 (*((SQInt32 *)&_i_._arg1))
#define arg2 (_i_._arg2)
#define arg3 (_i_._arg3)
#define sarg3 ((SQInteger)*((signed char *)&_i_._arg3))

SQRESULT SQVM::Suspend()
{
    if (_suspended)
        return sq_throwerror(this, _SC("cannot suspend an already suspended vm"));
    if (_nnativecalls!=2)
        return sq_throwerror(this, _SC("cannot suspend through native calls/metamethods"));
    return SQ_SUSPEND_FLAG;
}

void SQVM::PopVarArgs(VarArgs &vargs)
{
    for(SQInteger n = 0; n< vargs.size; n++)
        _vargsstack.pop_back();
}

#define _FINISH(howmuchtojump) {jump = howmuchtojump; return true; }
bool SQVM::FOREACH_OP(SQObjectPtr &o1,SQObjectPtr &o2,SQObjectPtr
&o3,SQObjectPtr &o4,SQInteger arg_2,int exitpos,int &jump)
{
    SQInteger nrefidx;
    switch(type(o1)) {
    case OT_TABLE:
        if((nrefidx = _table(o1)->Next(false,o4, o2, o3)) == -1) _FINISH(exitpos);
        o4 = (SQInteger)nrefidx; _FINISH(1);
    case OT_ARRAY:
        if((nrefidx = _array(o1)->Next(o4, o2, o3)) == -1) _FINISH(exitpos);
        o4 = (SQInteger) nrefidx; _FINISH(1);
    case OT_STRING:
        if((nrefidx = _string(o1)->Next(o4, o2, o3)) == -1)_FINISH(exitpos);
        o4 = (SQInteger)nrefidx; _FINISH(1);
    case OT_CLASS:
        if((nrefidx = _class(o1)->Next(o4, o2, o3)) == -1)_FINISH(exitpos);
        o4 = (SQInteger)nrefidx; _FINISH(1);
    case OT_USERDATA:
    case OT_INSTANCE:
        if(_delegable(o1)->_delegate) {
            SQObjectPtr itr;
            Push(o1);
            Push(o4);
            if(CallMetaMethod(_delegable(o1), MT_NEXTI, 2, itr)){
                o4 = o2 = itr;
                if(type(itr) == OT_NULL) _FINISH(exitpos);
                if(!Get(o1, itr, o3, false,false)) {
                    Raise_Error(_SC("_nexti returned an invalid idx"));
                    return false;
                }
                _FINISH(1);
            }
            Raise_Error(_SC("_nexti failed"));
            return false;
        }
        break;
    case OT_GENERATOR:
        if(_generator(o1)->_state == SQGenerator::eDead) _FINISH(exitpos);
        if(_generator(o1)->_state == SQGenerator::eSuspended) {
            SQInteger idx = 0;
            if(type(o4) == OT_INTEGER) {
                idx = _integer(o4) + 1;
            }
            o2 = idx;
            o4 = idx;
            _generator(o1)->Resume(this, arg_2+1);
            _FINISH(0);
        }
    default:
        Raise_Error(_SC("cannot iterate %s"), GetTypeName(o1));
    }
    return false; //cannot be hit(just to avoid warnings)
}

bool SQVM::DELEGATE_OP(SQObjectPtr &trg,SQObjectPtr &o1,SQObjectPtr &o2)
{
    if(type(o1) != OT_TABLE) { Raise_Error(_SC("delegating a '%s'"), GetTypeName(o1)); return false; }
    switch(type(o2)) {
    case OT_TABLE:
        if(!_table(o1)->SetDelegate(_table(o2))){
            Raise_Error(_SC("delegate cycle detected"));
            return false;
        }
        break;
    case OT_NULL:
        _table(o1)->SetDelegate(NULL);
        break;
    default:
        Raise_Error(_SC("using '%s' as delegate"), GetTypeName(o2));
        return false;
        break;
    }
    trg = o1;
    return true;
}
#define COND_LITERAL (arg3!=0?ci->_literals[arg1]:STK(arg1))

#define _GUARD(exp) { if(!exp) { Raise_Error(_lasterror); SQ_THROW();} }

#define SQ_THROW() { goto exception_trap; }

bool SQVM::CLOSURE_OP(SQObjectPtr &target, SQFunctionProto *func)
{
    SQInteger nouters;
    SQClosure *closure = SQClosure::Create(_ss(this), func);
    if((nouters = func->_noutervalues)) {
        closure->_outervalues.reserve(nouters);
        for(SQInteger i = 0; i<nouters; i++) {
            SQOuterVar &v = func->_outervalues[i];
            switch(v._type){
            case otSYMBOL:
                closure->_outervalues.push_back(_null_);
                if(!Get(_stack._vals[_stackbase]/*STK(0)*/, v._src, closure->_outervalues.top(), false,true))
                {Raise_IdxError(v._src); return false; }
                break;
            case otLOCAL:
                closure->_outervalues.push_back(_stack._vals[_stackbase+_integer(v._src)]);
                break;
            case otOUTER:
                closure->_outervalues.push_back(_closure(ci->_closure)->_outervalues[_integer(v._src)]);
                break;
            }
        }
    }
    SQInteger ndefparams;
    if((ndefparams = func->_ndefaultparams)) {
        closure->_defaultparams.reserve(ndefparams);
        for(SQInteger i = 0; i < ndefparams; i++) {
            SQInteger spos = func->_defaultparams[i];
            closure->_defaultparams.push_back(_stack._vals[_stackbase + spos]);
        }
    }
    target = closure;
    return true;

}

// C::B patch: Fix shadowed variable warning
bool SQVM::GETVARGV_OP(SQObjectPtr &target,SQObjectPtr &index,CallInfo *callinfo)
{
    if(callinfo->_vargs.size == 0) {
        Raise_Error(_SC("the function doesn't have var args"));
        return false;
    }
    if(!sq_isnumeric(index)){
        Raise_Error(_SC("indexing 'vargv' with %s"),GetTypeName(index));
        return false;
    }
    SQInteger idx = tointeger(index);
    if(idx < 0 || idx >= callinfo->_vargs.size){ Raise_Error(_SC("vargv index out of range")); return false; }
    target = _vargsstack[callinfo->_vargs.base+idx];
    return true;
}

bool SQVM::CLASS_OP(SQObjectPtr &target,SQInteger baseclass,SQInteger attributes)
{
    SQClass *base = NULL;
    SQObjectPtr attrs;
    if(baseclass != -1) {
        if(type(_stack._vals[_stackbase+baseclass]) != OT_CLASS) { Raise_Error(_SC("trying to inherit from a %s"),GetTypeName(_stack._vals[_stackbase+baseclass])); return false; }
        base = _class(_stack._vals[_stackbase + baseclass]);
    }
    if(attributes != MAX_FUNC_STACKSIZE) {
        attrs = _stack._vals[_stackbase+attributes];
    }
    target = SQClass::Create(_ss(this),base);
    if(type(_class(target)->_metamethods[MT_INHERITED]) != OT_NULL) {
        int nparams = 2;
        SQObjectPtr ret;
        Push(target); Push(attrs);
        Call(_class(target)->_metamethods[MT_INHERITED],nparams,_top - nparams, ret, false);
        Pop(nparams);
    }
    _class(target)->_attributes = attrs;
    return true;
}



bool SQVM::IsEqual(SQObjectPtr &o1,SQObjectPtr &o2,bool &res)
{
    if(type(o1) == type(o2)) {
        res = ((_rawval(o1) == _rawval(o2)?true:false));
    }
    else {
        if(sq_isnumeric(o1) && sq_isnumeric(o2)) {
            SQInteger cmpres;
            if(!ObjCmp(o1, o2,cmpres)) return false;
            res = (cmpres == 0);
        }
        else {
            res = false;
        }
    }
    return true;
}

bool SQVM::IsFalse(SQObjectPtr &o)
{
    // C::B patch: Eliminate compiler warnings
    if(( (type(o) & SQOBJECT_CANBEFALSE) && ( (type(o) == OT_FLOAT) && (_float(o) == SQFloat(0.0))) )
        || (_integer(o) == 0) ) { //OT_NULL|OT_INTEGER|OT_BOOL
        return true;
    }
    return false;
}

bool SQVM::GETPARENT_OP(SQObjectPtr &o,SQObjectPtr &target)
{
    switch(type(o)) {
        case OT_TABLE: target = _table(o)->_delegate?SQObjectPtr(_table(o)->_delegate):_null_;
            break;
        case OT_CLASS: target = _class(o)->_base?_class(o)->_base:_null_;
            break;
        default:
            Raise_Error(_SC("the %s type doesn't have a parent slot"), GetTypeName(o));
            return false;
    }
    return true;
}

bool SQVM::Execute(SQObjectPtr &closure, SQInteger target, SQInteger nargs, SQInteger stackbase,SQObjectPtr &outres, SQBool raiseerror,ExecutionType et)
{
    if ((_nnativecalls + 1) > MAX_NATIVE_CALLS) { Raise_Error(_SC("Native stack overflow")); return false; }
    _nnativecalls++;
    AutoDec ad(&_nnativecalls);
    SQInteger traps = 0;
    //temp_reg vars for OP_CALL
    SQInteger ct_target;
    SQInteger ct_stackbase;
    bool ct_tailcall;

    switch(et) {
        case ET_CALL: {
            SQInteger last_top = _top;
            temp_reg = closure;
            if(!StartCall(_closure(temp_reg), _top - nargs, nargs, stackbase, false)) {
                //call the handler if there are no calls in the stack, if not relies on the previous node
                if(ci == NULL) CallErrorHandler(_lasterror);
                return false;
            }
            if (_funcproto(_closure(temp_reg)->_function)->_bgenerator) {
                // C::B patch: Eliminate compiler warnings
                //SQFunctionProto *f = _funcproto(_closure(temp_reg)->_function);
                SQGenerator *gen = SQGenerator::Create(_ss(this), _closure(temp_reg));
                _GUARD(gen->Yield(this));
                Return(1, ci->_target, temp_reg);
                outres = gen;
                CLEARSTACK(last_top);
                return true;
            }
            ci->_root = SQTrue;
                      }
            break;
        case ET_RESUME_GENERATOR: _generator(closure)->Resume(this, target); ci->_root = SQTrue; traps += ci->_etraps; break;
        case ET_RESUME_VM:
        case ET_RESUME_THROW_VM:
            traps = _suspended_traps;
            ci->_root = _suspended_root;
            ci->_vargs = _suspend_varargs;
            _suspended = SQFalse;
            if(et  == ET_RESUME_THROW_VM) { SQ_THROW(); }
            break;
    }

exception_restore:
    //
    {
        for(;;)
        {
            const SQInstruction &_i_ = *ci->_ip++;
            //dumpstack(_stackbase);
            //scprintf("\n[%d] %s %d %d %d %d\n",ci->_ip-ci->_iv->_vals,g_InstrDesc[_i_.op].name,arg0,arg1,arg2,arg3);
            switch(_i_.op)
            {
            case _OP_LINE:
                if(type(_debughook) != OT_NULL && _rawval(_debughook) != _rawval(ci->_closure))
                    CallDebugHook(_SC('l'),arg1);
                continue;
            case _OP_LOAD: TARGET = ci->_literals[arg1]; continue;
            case _OP_LOADINT: TARGET = (SQInteger)arg1; continue;
            case _OP_LOADFLOAT: TARGET = *((SQFloat *)&arg1); continue;
            case _OP_DLOAD: TARGET = ci->_literals[arg1]; STK(arg2) = ci->_literals[arg3];continue;
            case _OP_TAILCALL:
                temp_reg = STK(arg1);
                if (type(temp_reg) == OT_CLOSURE && !_funcproto(_closure(temp_reg)->_function)->_bgenerator){
                    ct_tailcall = true;
                    if(ci->_vargs.size) PopVarArgs(ci->_vargs);
                    for (SQInteger i = 0; i < arg3; i++) STK(i) = STK(arg2 + i);
                    ct_target = ci->_target;
                    ct_stackbase = _stackbase;
                    goto common_call;
                }
            case _OP_CALL: {
                    ct_tailcall = false;
                    ct_target = arg0;
                    temp_reg = STK(arg1);
                    ct_stackbase = _stackbase+arg2;

common_call:
                    SQObjectPtr clo = temp_reg;
                    SQInteger last_top = _top;
                    switch (type(clo)) {
                    case OT_CLOSURE:{
                        _GUARD(StartCall(_closure(clo), ct_target, arg3, ct_stackbase, ct_tailcall));
                        if (_funcproto(_closure(clo)->_function)->_bgenerator) {
                            SQGenerator *gen = SQGenerator::Create(_ss(this), _closure(clo));
                            _GUARD(gen->Yield(this));
                            Return(1, ct_target, clo);
                            STK(ct_target) = gen;
                            CLEARSTACK(last_top);
                            continue;
                        }
                        }
                        continue;
                    case OT_NATIVECLOSURE: {
                        bool suspend;
                        _GUARD(CallNative(_nativeclosure(clo), arg3, ct_stackbase, clo,suspend));
                        if(suspend){
                            _suspended = SQTrue;
                            _suspended_target = ct_target;
                            _suspended_root = ci->_root;
                            _suspended_traps = traps;
                            _suspend_varargs = ci->_vargs;
                            outres = clo;
                            return true;
                        }
                        if(ct_target != -1) { //skip return value for constructors
                            STK(ct_target) = clo;
                        }
                                           }
                        continue;
                    case OT_CLASS:{
                        SQObjectPtr inst;
                        _GUARD(CreateClassInstance(_class(clo),inst,temp_reg));
                        STK(ct_target) = inst;
                        ct_target = -1; //fakes return value target so that is not overwritten by the constructor
                        if(type(temp_reg) != OT_NULL) {
                            _stack._vals[ct_stackbase] = inst;
                            goto common_call; //hard core spaghetti code(reissues the OP_CALL to invoke the constructor)
                        }
                        }
                        break;
                    case OT_TABLE:
                    case OT_USERDATA:
                    case OT_INSTANCE:
                        {
                        Push(clo);
                        for (SQInteger i = 0; i < arg3; i++) Push(STK(arg2 + i));
                        if (_delegable(clo) && CallMetaMethod(_delegable(clo), MT_CALL, arg3+1, clo)){
                            STK(ct_target) = clo;
                            break;
                        }
                        Raise_Error(_SC("attempt to call '%s'"), GetTypeName(clo));
                        SQ_THROW();
                      }
                    default:
                        Raise_Error(_SC("attempt to call '%s'"), GetTypeName(clo));
                        SQ_THROW();
                    }
                }
                  continue;
            case _OP_PREPCALL:
            case _OP_PREPCALLK:
                {
                    SQObjectPtr &key = _i_.op == _OP_PREPCALLK?(ci->_literals)[arg1]:STK(arg1);
                    SQObjectPtr &o = STK(arg2);
                    if (!Get(o, key, temp_reg,false,true)) {
                        if(type(o) == OT_CLASS) { //hack?
                            if(_class_ddel->Get(key,temp_reg)) {
                                STK(arg3) = o;
                                TARGET = temp_reg;
                                continue;
                            }
                        }
                        { Raise_IdxError(key); SQ_THROW();}
                    }

                    STK(arg3) = type(o) == OT_CLASS?STK(0):o;
                    TARGET = temp_reg;
                }
                continue;
            case _OP_GETK:
                if (!Get(STK(arg2), ci->_literals[arg1], temp_reg, false,true)) { Raise_IdxError(ci->_literals[arg1]); SQ_THROW();}
                TARGET = temp_reg;
                continue;
            case _OP_MOVE: TARGET = STK(arg1); continue;
            case _OP_NEWSLOT:
                _GUARD(NewSlot(STK(arg1), STK(arg2), STK(arg3),false));
                if(arg0 != arg3) TARGET = STK(arg3);
                continue;
            case _OP_DELETE: _GUARD(DeleteSlot(STK(arg1), STK(arg2), TARGET)); continue;
            case _OP_SET:
                if (!Set(STK(arg1), STK(arg2), STK(arg3),true)) { Raise_IdxError(STK(arg2)); SQ_THROW(); }
                if (arg0 != arg3) TARGET = STK(arg3);
                continue;
            case _OP_GET:
                if (!Get(STK(arg1), STK(arg2), temp_reg, false,true)) { Raise_IdxError(STK(arg2)); SQ_THROW(); }
                TARGET = temp_reg;
                continue;
            case _OP_EQ:{
                bool res;
                if(!IsEqual(STK(arg2),COND_LITERAL,res)) { SQ_THROW(); }
                TARGET = res?_true_:_false_;
                }continue;
            case _OP_NE:{
                bool res;
                if(!IsEqual(STK(arg2),COND_LITERAL,res)) { SQ_THROW(); }
                TARGET = (!res)?_true_:_false_;
                } continue;
            case _OP_ARITH: _GUARD(ARITH_OP( arg3 , temp_reg, STK(arg2), STK(arg1))); TARGET = temp_reg; continue;
            case _OP_BITW:  _GUARD(BW_OP( arg3,TARGET,STK(arg2),STK(arg1))); continue;
            case _OP_RETURN:
                if(ci->_generator) {
                    ci->_generator->Kill();
                }
                if(Return(arg0, arg1, temp_reg)){
                    assert(traps==0);
                    outres = temp_reg;
                    return true;
                }
                continue;
            case _OP_LOADNULLS:{ for(SQInt32 n=0; n < arg1; n++) STK(arg0+n) = _null_; }continue;
            case _OP_LOADROOTTABLE: TARGET = _roottable; continue;
            case _OP_LOADBOOL: TARGET = arg1?_true_:_false_; continue;
            case _OP_DMOVE: STK(arg0) = STK(arg1); STK(arg2) = STK(arg3); continue;
            case _OP_JMP: ci->_ip += (sarg1); continue;
            case _OP_JNZ: if(!IsFalse(STK(arg0))) ci->_ip+=(sarg1); continue;
            case _OP_JZ: if(IsFalse(STK(arg0))) ci->_ip+=(sarg1); continue;
            case _OP_LOADFREEVAR: TARGET = _closure(ci->_closure)->_outervalues[arg1]; continue;
            case _OP_VARGC: TARGET = SQInteger(ci->_vargs.size); continue;
            case _OP_GETVARGV:
                if(!GETVARGV_OP(TARGET,STK(arg1),ci)) { SQ_THROW(); }
                continue;
            case _OP_NEWTABLE: TARGET = SQTable::Create(_ss(this), arg1); continue;
            case _OP_NEWARRAY: TARGET = SQArray::Create(_ss(this), 0); _array(TARGET)->Reserve(arg1); continue;
            case _OP_APPENDARRAY: _array(STK(arg0))->Append(COND_LITERAL);  continue;
            case _OP_GETPARENT: _GUARD(GETPARENT_OP(STK(arg1),TARGET)); continue;
            case _OP_COMPARITH: _GUARD(DerefInc(arg3, TARGET, STK((((SQUnsignedInteger)arg1&0xFFFF0000)>>16)), STK(arg2), STK(arg1&0x0000FFFF), false)); continue;
            case _OP_COMPARITHL: _GUARD(LOCAL_INC(arg3, TARGET, STK(arg1), STK(arg2))); continue;
            case _OP_INC: {SQObjectPtr o(sarg3); _GUARD(DerefInc('+',TARGET, STK(arg1), STK(arg2), o, false));} continue;
            case _OP_INCL: {SQObjectPtr o(sarg3); _GUARD(LOCAL_INC('+',TARGET, STK(arg1), o));} continue;
            case _OP_PINC: {SQObjectPtr o(sarg3); _GUARD(DerefInc('+',TARGET, STK(arg1), STK(arg2), o, true));} continue;
            case _OP_PINCL: {SQObjectPtr o(sarg3); _GUARD(PLOCAL_INC('+',TARGET, STK(arg1), o));} continue;
            case _OP_CMP:   _GUARD(CMP_OP((CmpOP)arg3,STK(arg2),STK(arg1),TARGET))  continue;
            case _OP_EXISTS: TARGET = Get(STK(arg1), STK(arg2), temp_reg, true,false)?_true_:_false_;continue;
            case _OP_INSTANCEOF:
                if(type(STK(arg1)) != OT_CLASS || type(STK(arg2)) != OT_INSTANCE)
                {Raise_Error(_SC("cannot apply instanceof between a %s and a %s"),GetTypeName(STK(arg1)),GetTypeName(STK(arg2))); SQ_THROW();}
                TARGET = _instance(STK(arg2))->InstanceOf(_class(STK(arg1)))?_true_:_false_;
                continue;
            case _OP_AND:
                if(IsFalse(STK(arg2))) {
                    TARGET = STK(arg2);
                    ci->_ip += (sarg1);
                }
                continue;
            case _OP_OR:
                if(!IsFalse(STK(arg2))) {
                    TARGET = STK(arg2);
                    ci->_ip += (sarg1);
                }
                continue;
            case _OP_NEG: _GUARD(NEG_OP(TARGET,STK(arg1))); continue;
            case _OP_NOT: TARGET = (IsFalse(STK(arg1))?_true_:_false_); continue;
            case _OP_BWNOT:
                if(type(STK(arg1)) == OT_INTEGER) {
                    SQInteger t = _integer(STK(arg1));
                    TARGET = SQInteger(~t);
                    continue;
                }
                Raise_Error(_SC("attempt to perform a bitwise op on a %s"), GetTypeName(STK(arg1)));
                SQ_THROW();
            case _OP_CLOSURE: {
                SQClosure *c = ci->_closure._unVal.pClosure;
                SQFunctionProto *fp = c->_function._unVal.pFunctionProto;
                if(!CLOSURE_OP(TARGET,fp->_functions[arg1]._unVal.pFunctionProto)) { SQ_THROW(); }
                continue;
            }
            case _OP_YIELD:{
                if(ci->_generator) {
                    if(sarg1 != MAX_FUNC_STACKSIZE) temp_reg = STK(arg1);
                    _GUARD(ci->_generator->Yield(this));
                    traps -= ci->_etraps;
                    if(sarg1 != MAX_FUNC_STACKSIZE) STK(arg1) = temp_reg;
                }
                else { Raise_Error(_SC("trying to yield a '%s',only genenerator can be yielded"), GetTypeName(ci->_generator)); SQ_THROW();}
                if(Return(arg0, arg1, temp_reg)){
                    assert(traps == 0);
                    outres = temp_reg;
                    return true;
                }

                }
                continue;
            case _OP_RESUME:
                if(type(STK(arg1)) != OT_GENERATOR){ Raise_Error(_SC("trying to resume a '%s',only genenerator can be resumed"), GetTypeName(STK(arg1))); SQ_THROW();}
                _GUARD(_generator(STK(arg1))->Resume(this, arg0));
                traps += ci->_etraps;
                continue;
            case _OP_FOREACH:{ int tojump;
                _GUARD(FOREACH_OP(STK(arg0),STK(arg2),STK(arg2+1),STK(arg2+2),arg2,sarg1,tojump));
                ci->_ip += tojump; }
                continue;
            case _OP_POSTFOREACH:
                assert(type(STK(arg0)) == OT_GENERATOR);
                if(_generator(STK(arg0))->_state == SQGenerator::eDead)
                    ci->_ip += (sarg1 - 1);
                continue;
            case _OP_DELEGATE: _GUARD(DELEGATE_OP(TARGET,STK(arg1),STK(arg2))); continue;
            case _OP_CLONE:
                if(!Clone(STK(arg1), TARGET))
                { Raise_Error(_SC("cloning a %s"), GetTypeName(STK(arg1))); SQ_THROW();}
                continue;
            case _OP_TYPEOF: TypeOf(STK(arg1), TARGET); continue;
            case _OP_PUSHTRAP:{
                SQInstruction *_iv = _funcproto(_closure(ci->_closure)->_function)->_instructions;
                _etraps.push_back(SQExceptionTrap(_top,_stackbase, &_iv[(ci->_ip-_iv)+arg1], arg0)); traps++;
                ci->_etraps++;
                              }
                continue;
            case _OP_POPTRAP: {
                for(SQInteger i = 0; i < arg0; i++) {
                    _etraps.pop_back(); traps--;
                    ci->_etraps--;
                }
                              }
                continue;
            case _OP_THROW: Raise_Error(TARGET); SQ_THROW(); continue;
            case _OP_CLASS: _GUARD(CLASS_OP(TARGET,arg1,arg2)); continue;
            case _OP_NEWSLOTA:
                bool bstatic = (arg0&NEW_SLOT_STATIC_FLAG)?true:false;
                if(type(STK(arg1)) == OT_CLASS) {
                    if(type(_class(STK(arg1))->_metamethods[MT_NEWMEMBER]) != OT_NULL ) {
                        Push(STK(arg1)); Push(STK(arg2)); Push(STK(arg3));
                        Push((arg0&NEW_SLOT_ATTRIBUTES_FLAG) ? STK(arg2-1) : _null_);
                        Push(bstatic);
                        int nparams = 5;
                        if(Call(_class(STK(arg1))->_metamethods[MT_NEWMEMBER], nparams, _top - nparams, temp_reg,SQFalse)) {
                            Pop(nparams);
                            continue;
                        }
                    }
                }
                _GUARD(NewSlot(STK(arg1), STK(arg2), STK(arg3),bstatic));
                if((arg0&NEW_SLOT_ATTRIBUTES_FLAG)) {
                    _class(STK(arg1))->SetAttributes(STK(arg2),STK(arg2-1));
                }
                continue;
            }

        }
    }
exception_trap:
    {
        SQObjectPtr currerror = _lasterror;
//      dumpstack(_stackbase);
        SQInteger n = 0;
        SQInteger last_top = _top;
        if(ci) {
            if(_ss(this)->_notifyallexceptions) CallErrorHandler(currerror);

            if(traps) {
                do {
                    if(ci->_etraps > 0) {
                        // C::B patch: Avoid compiler warnings about shadowing params
                        SQExceptionTrap &etrap = _etraps.top();
                        ci->_ip = etrap._ip;
                        _top = etrap._stacksize;
                        _stackbase = etrap._stackbase;
                        _stack._vals[_stackbase+etrap._extarget] = currerror;
                        _etraps.pop_back(); traps--; ci->_etraps--;
                        CLEARSTACK(last_top);
                        goto exception_restore;
                    }
                    //if is a native closure
                    if(type(ci->_closure) != OT_CLOSURE && n)
                        break;
                    if(ci->_generator) ci->_generator->Kill();
                    PopVarArgs(ci->_vargs);
                    POP_CALLINFO(this);
                    n++;
                } while(_callsstacksize);
            }
            else {
                //call the hook
                if(raiseerror && !_ss(this)->_notifyallexceptions)
                    CallErrorHandler(currerror);
            }
            //remove call stack until a C function is found or the cstack is empty
            if(ci) do {
                SQBool exitafterthisone = ci->_root;
                if(ci->_generator) ci->_generator->Kill();
                _stackbase -= ci->_prevstkbase;
                _top = _stackbase + ci->_prevtop;
                PopVarArgs(ci->_vargs);
                POP_CALLINFO(this);
                if( (ci && type(ci->_closure) != OT_CLOSURE) || exitafterthisone) break;
            } while(_callsstacksize);

            CLEARSTACK(last_top);
        }
        _lasterror = currerror;
        return false;
    }
    assert(0);
    // C::B patch: Avoid compiler warnings
    return false;
}

bool SQVM::CreateClassInstance(SQClass *theclass, SQObjectPtr &inst, SQObjectPtr &constructor)
{
    inst = theclass->CreateInstance();
    if(!theclass->Get(_ss(this)->_constructoridx,constructor)) {
        constructor = _null_;
    }
    return true;
}

void SQVM::CallErrorHandler(SQObjectPtr &error)
{
    if(type(_errorhandler) != OT_NULL) {
        SQObjectPtr out;
        Push(_roottable); Push(error);
        Call(_errorhandler, 2, _top-2, out,SQFalse);
        Pop(2);
    }
}

void SQVM::CallDebugHook(SQInteger type,SQInteger forcedline)
{
    // C::B patch: Avoid compiler warnings about shadowing params
    SQObjectPtr tmp_reg;
    SQInteger nparams=5;
    SQFunctionProto *func=_funcproto(_closure(ci->_closure)->_function);
    Push(_roottable); Push(type); Push(func->_sourcename); Push(forcedline?forcedline:func->GetLine(ci->_ip)); Push(func->_name);
    Call(_debughook,nparams,_top-nparams,tmp_reg,SQFalse);
    Pop(nparams);
}

bool SQVM::CallNative(SQNativeClosure *nclosure,SQInteger nargs,SQInteger stackbase,SQObjectPtr &retval,bool &suspend)
{
    if (_nnativecalls + 1 > MAX_NATIVE_CALLS) { Raise_Error(_SC("Native stack overflow")); return false; }
    SQInteger nparamscheck = nclosure->_nparamscheck;
    if(((nparamscheck > 0) && (nparamscheck != nargs))
        || ((nparamscheck < 0) && (nargs < (-nparamscheck)))) {
        Raise_Error(_SC("wrong number of parameters"));
        return false;
        }

    SQInteger tcs;
    if((tcs = nclosure->_typecheck.size())) {
        for(SQInteger i = 0; i < nargs && i < tcs; i++)
            if((nclosure->_typecheck._vals[i] != -1) && !(type(_stack._vals[stackbase+i]) & nclosure->_typecheck[i])) {
                Raise_ParamTypeError(i,nclosure->_typecheck._vals[i],type(_stack._vals[stackbase+i]));
                return false;
            }
    }
    _nnativecalls++;
    if ((_top + MIN_STACK_OVERHEAD) > (SQInteger)_stack.size()) {
        _stack.resize(_stack.size() + (MIN_STACK_OVERHEAD<<1));
    }
    SQInteger oldtop = _top;
    SQInteger oldstackbase = _stackbase;
    _top = stackbase + nargs;
    CallInfo lci;
    lci._closure = nclosure;
    lci._generator = NULL;
    lci._etraps = 0;
    lci._prevstkbase = (SQInt32) (stackbase - _stackbase);
    lci._ncalls = 1;
    lci._prevtop = (SQInt32) (oldtop - oldstackbase);
    PUSH_CALLINFO(this, lci);
    _stackbase = stackbase;
    //push free variables
    SQInteger outers = nclosure->_outervalues.size();
    for (SQInteger i = 0; i < outers; i++) {
        Push(nclosure->_outervalues[i]);
    }

    if(type(nclosure->_env) == OT_WEAKREF) {
        _stack[stackbase] = _weakref(nclosure->_env)->_obj;
    }


    SQInteger ret = (nclosure->_function)(this);
    _nnativecalls--;
    suspend = false;
    if( ret == SQ_SUSPEND_FLAG) suspend = true;
    else if (ret < 0) {
        _stackbase = oldstackbase;
        _top = oldtop;
        POP_CALLINFO(this);
        Raise_Error(_lasterror);
        return false;
    }

    if (ret != 0){ retval = TOP(); TOP().Null(); }
    else { retval = _null_; }
    _stackbase = oldstackbase;
    _top = oldtop;
    POP_CALLINFO(this);
    return true;
}

bool SQVM::Get(const SQObjectPtr &self,const SQObjectPtr &key,SQObjectPtr &dest,bool raw, bool fetchroot)
{
    switch(type(self)){
    case OT_TABLE:
        if(_table(self)->Get(key,dest))return true;
        break;
    case OT_ARRAY:
        if(sq_isnumeric(key)){
            return _array(self)->Get(tointeger(key),dest);
        }
        break;
    case OT_INSTANCE:
        if(_instance(self)->Get(key,dest)) return true;
        break;
    default:break; //shut up compiler
    }
    if(FallBackGet(self,key,dest,raw)) return true;

    if(fetchroot) {
        if(_rawval(STK(0)) == _rawval(self) &&
            type(STK(0)) == type(self)) {
                return _table(_roottable)->Get(key,dest);
        }
    }
    return false;
}

bool SQVM::FallBackGet(const SQObjectPtr &self,const SQObjectPtr &key,SQObjectPtr &dest,bool raw)
{
    switch(type(self)){
    case OT_CLASS:
        return _class(self)->Get(key,dest);
        break;
    case OT_TABLE:
    case OT_USERDATA:
        //delegation
        if(_delegable(self)->_delegate) {
            if(Get(SQObjectPtr(_delegable(self)->_delegate),key,dest,raw,false))
                return true;
            if(raw)return false;
            Push(self);Push(key);
            if(CallMetaMethod(_delegable(self),MT_GET,2,dest))
                return true;
        }
        if(type(self) == OT_TABLE) {
            if(raw) return false;
            return _table_ddel->Get(key,dest);
        }
        return false;
        break;
    case OT_ARRAY:
        if(raw)return false;
        return _array_ddel->Get(key,dest);
    case OT_STRING:
        if(sq_isnumeric(key)){
            SQInteger n=tointeger(key);
            if(abs((int)n)<_string(self)->_len){
                if(n<0)n=_string(self)->_len-n;
                dest=SQInteger(_stringval(self)[n]);
                return true;
            }
            return false;
        }
        else {
            if(raw)return false;
            return _string_ddel->Get(key,dest);
        }
        break;
    case OT_INSTANCE:
        if(raw)return false;
        Push(self);Push(key);
        if(!CallMetaMethod(_delegable(self),MT_GET,2,dest)) {
            return _instance_ddel->Get(key,dest);
        }
        return true;
    case OT_INTEGER:case OT_FLOAT:case OT_BOOL:
        if(raw)return false;
        return _number_ddel->Get(key,dest);
    case OT_GENERATOR:
        if(raw)return false;
        return _generator_ddel->Get(key,dest);
    case OT_CLOSURE: case OT_NATIVECLOSURE:
        if(raw)return false;
        return _closure_ddel->Get(key,dest);
    case OT_THREAD:
        if(raw)return false;
        return  _thread_ddel->Get(key,dest);
    case OT_WEAKREF:
        if(raw)return false;
        return  _weakref_ddel->Get(key,dest);
    default:return false;
    }
    return false;
}

bool SQVM::Set(const SQObjectPtr &self,const SQObjectPtr &key,const SQObjectPtr &val,bool fetchroot)
{
    switch(type(self)){
    case OT_TABLE:
        if(_table(self)->Set(key,val))
            return true;
        if(_table(self)->_delegate) {
            if(Set(_table(self)->_delegate,key,val,false)) {
                return true;
            }
        }
        //keeps going
    case OT_USERDATA:
        if(_delegable(self)->_delegate) {
            SQObjectPtr t;
            Push(self);Push(key);Push(val);
            if(CallMetaMethod(_delegable(self),MT_SET,3,t)) return true;
        }
        break;
    case OT_INSTANCE:{
        if(_instance(self)->Set(key,val))
            return true;
        SQObjectPtr t;
        Push(self);Push(key);Push(val);
        if(CallMetaMethod(_delegable(self),MT_SET,3,t)) return true;
        }
        break;
    case OT_ARRAY:
        if(!sq_isnumeric(key)) {Raise_Error(_SC("indexing %s with %s"),GetTypeName(self),GetTypeName(key)); return false; }
        return _array(self)->Set(tointeger(key),val);
    default:
        Raise_Error(_SC("trying to set '%s'"),GetTypeName(self));
        return false;
    }
    if(fetchroot) {
        if(_rawval(STK(0)) == _rawval(self) &&
            type(STK(0)) == type(self)) {
                return _table(_roottable)->Set(key,val);
            }
    }
    return false;
}

bool SQVM::Clone(const SQObjectPtr &self,SQObjectPtr &target)
{
    // C::B patch: Avoid compiler warnings about shadowing params
    SQObjectPtr tmp_reg;
    SQObjectPtr newobj;
    switch(type(self)){
    case OT_TABLE:
        newobj = _table(self)->Clone();
        goto cloned_mt;
    case OT_INSTANCE:
        newobj = _instance(self)->Clone(_ss(this));
cloned_mt:
        if(_delegable(newobj)->_delegate){
            Push(newobj);
            Push(self);
            CallMetaMethod(_delegable(newobj),MT_CLONED,2,tmp_reg);
        }
        target = newobj;
        return true;
    case OT_ARRAY:
        target = _array(self)->Clone();
        return true;
    default: return false;
    }
}

bool SQVM::NewSlot(const SQObjectPtr &self,const SQObjectPtr &key,const SQObjectPtr &val,bool bstatic)
{
    if(type(key) == OT_NULL) { Raise_Error(_SC("null cannot be used as index")); return false; }
    switch(type(self)) {
    case OT_TABLE: {
        bool rawcall = true;
        if(_table(self)->_delegate) {
            SQObjectPtr res;
            if(!_table(self)->Get(key,res)) {
                Push(self);Push(key);Push(val);
                rawcall = !CallMetaMethod(_table(self),MT_NEWSLOT,3,res);
            }
        }
        if(rawcall) _table(self)->NewSlot(key,val); //cannot fail

        break;}
    case OT_INSTANCE: {
        SQObjectPtr res;
        Push(self);Push(key);Push(val);
        if(!CallMetaMethod(_instance(self),MT_NEWSLOT,3,res)) {
            Raise_Error(_SC("class instances do not support the new slot operator"));
            return false;
        }
        break;}
    case OT_CLASS:
        if(!_class(self)->NewSlot(_ss(this),key,val,bstatic)) {
            if(_class(self)->_locked) {
                Raise_Error(_SC("trying to modify a class that has already been instantiated"));
                return false;
            }
            else {
                SQObjectPtr oval = PrintObjVal(key);
                Raise_Error(_SC("the property '%s' already exists"),_stringval(oval));
                return false;
            }
        }
        break;
    default:
        Raise_Error(_SC("indexing %s with %s"),GetTypeName(self),GetTypeName(key));
        return false;
        break;
    }
    return true;
}

bool SQVM::DeleteSlot(const SQObjectPtr &self,const SQObjectPtr &key,SQObjectPtr &res)
{
    switch(type(self)) {
    case OT_TABLE:
    case OT_INSTANCE:
    case OT_USERDATA: {
        SQObjectPtr t;
        bool handled = false;
        if(_delegable(self)->_delegate) {
            Push(self);Push(key);
            handled = CallMetaMethod(_delegable(self),MT_DELSLOT,2,t);
        }

        if(!handled) {
            if(type(self) == OT_TABLE) {
                if(_table(self)->Get(key,t)) {
                    _table(self)->Remove(key);
                }
                else {
                    Raise_IdxError((SQObject &)key);
                    return false;
                }
            }
            else {
                Raise_Error(_SC("cannot delete a slot from %s"),GetTypeName(self));
                return false;
            }
        }
        res = t;
                }
        break;
    default:
        Raise_Error(_SC("attempt to delete a slot from a %s"),GetTypeName(self));
        return false;
    }
    return true;
}

bool SQVM::Call(SQObjectPtr &closure,SQInteger nparams,SQInteger stackbase,SQObjectPtr &outres,SQBool raiseerror)
{
#ifdef _DEBUG
SQInteger prevstackbase = _stackbase;
#endif
    switch(type(closure)) {
    case OT_CLOSURE:
        return Execute(closure, _top - nparams, nparams, stackbase,outres,raiseerror);
        break;
    case OT_NATIVECLOSURE:{
        bool suspend;
        return CallNative(_nativeclosure(closure), nparams, stackbase, outres,suspend);

                          }
        break;
    case OT_CLASS: {
        SQObjectPtr constr;
        SQObjectPtr temp;
        CreateClassInstance(_class(closure),outres,constr);
        if(type(constr) != OT_NULL) {
            _stack[stackbase] = outres;
            return Call(constr,nparams,stackbase,temp,raiseerror);
        }
        return true;
                   }
        break;
    default:
        return false;
    }
#ifdef _DEBUG
    if(!_suspended) {
        assert(_stackbase == prevstackbase);
    }
#endif
    return true;
}

bool SQVM::CallMetaMethod(SQDelegable *del,SQMetaMethod mm,SQInteger nparams,SQObjectPtr &outres)
{
    SQObjectPtr closure;
    if(del->GetMetaMethod(this, mm, closure)) {
        if(Call(closure, nparams, _top - nparams, outres, SQFalse)) {
            Pop(nparams);
            return true;
        }
    }
    Pop(nparams);
    return false;
}

void SQVM::Remove(SQInteger n) {
    n = (n >= 0)?n + _stackbase - 1:_top + n;
    for(SQInteger i = n; i < _top; i++){
        _stack[i] = _stack[i+1];
    }
    _stack[_top] = _null_;
    _top--;
}

void SQVM::Pop() {
    _stack[--_top] = _null_;
}

void SQVM::Pop(SQInteger n) {
    for(SQInteger i = 0; i < n; i++){
        _stack[--_top] = _null_;
    }
}

void SQVM::Push(const SQObjectPtr &o) { _stack[_top++] = o; }
SQObjectPtr &SQVM::Top() { return _stack[_top-1]; }
SQObjectPtr &SQVM::PopGet() { return _stack[--_top]; }
SQObjectPtr &SQVM::GetUp(SQInteger n) { return _stack[_top+n]; }
SQObjectPtr &SQVM::GetAt(SQInteger n) { return _stack[n]; }

#ifdef _DEBUG_DUMP
void SQVM::dumpstack(SQInteger stackbase,bool dumpall)
{
    SQInteger size=dumpall?_stack.size():_top;
    SQInteger n=0;
    scprintf(_SC("\n>>>>stack dump<<<<\n"));
    CallInfo &ci=_callsstack[_callsstacksize-1];
    scprintf(_SC("IP: %p\n"),ci._ip);
    scprintf(_SC("prev stack base: %d\n"),ci._prevstkbase);
    scprintf(_SC("prev top: %d\n"),ci._prevtop);
    for(SQInteger i=0;i<size;i++){
        SQObjectPtr &obj=_stack[i];
        if(stackbase==i)scprintf(_SC(">"));else scprintf(_SC(" "));
        scprintf(_SC("[%d]:"),n);
        switch(type(obj)){
        case OT_FLOAT:          scprintf(_SC("FLOAT %.3f"),_float(obj));break;
        case OT_INTEGER:        scprintf(_SC("INTEGER %d"),_integer(obj));break;
        case OT_BOOL:           scprintf(_SC("BOOL %s"),_integer(obj)?"true":"false");break;
        case OT_STRING:         scprintf(_SC("STRING %s"),_stringval(obj));break;
        case OT_NULL:           scprintf(_SC("NULL"));  break;
        case OT_TABLE:          scprintf(_SC("TABLE %p[%p]"),_table(obj),_table(obj)->_delegate);break;
        case OT_ARRAY:          scprintf(_SC("ARRAY %p"),_array(obj));break;
        case OT_CLOSURE:        scprintf(_SC("CLOSURE [%p]"),_closure(obj));break;
        case OT_NATIVECLOSURE:  scprintf(_SC("NATIVECLOSURE"));break;
        case OT_USERDATA:       scprintf(_SC("USERDATA %p[%p]"),_userdataval(obj),_userdata(obj)->_delegate);break;
        case OT_GENERATOR:      scprintf(_SC("GENERATOR %p"),_generator(obj));break;
        case OT_THREAD:         scprintf(_SC("THREAD [%p]"),_thread(obj));break;
        case OT_USERPOINTER:    scprintf(_SC("USERPOINTER %p"),_userpointer(obj));break;
        case OT_CLASS:          scprintf(_SC("CLASS %p"),_class(obj));break;
        case OT_INSTANCE:       scprintf(_SC("INSTANCE %p"),_instance(obj));break;
        case OT_WEAKREF:        scprintf(_SC("WEAKERF %p"),_weakref(obj));break;
        default:
            assert(0);
            break;
        };
        scprintf(_SC("\n"));
        ++n;
    }
}



#endif