#include "rar.hpp"

#include "rarvmtbl.cpp"

RarVM::RarVM()
{
  Mem=NULL;
}


RarVM::~RarVM()
{
  delete Mem;
}


void RarVM::Init()
{
  if (Mem==NULL)
    Mem=new byte[VM_MEMSIZE+4];
}


inline uint RarVM::GetValue(bool ByteMode,uint *Addr)
{
  if (ByteMode)
    return(*(byte *)Addr);
  else
  {
#ifdef BIG_ENDIAN
    byte *B=(byte *)Addr;
    return((uint)B[0]|((uint)B[1]<<8)|((uint)B[2]<<16)|((uint)B[3]<<24));
#else
    return(*Addr);
#endif
  }
}

#ifdef BIG_ENDIAN
  #define GET_VALUE(ByteMode,Addr) GetValue(ByteMode,(uint *)Addr)
#else
  #define GET_VALUE(ByteMode,Addr) ((ByteMode) ? (*(byte *)(Addr)):(*(uint *)(Addr)))
#endif


inline void RarVM::SetValue(bool ByteMode,uint *Addr,uint Value)
{
  if (ByteMode)
    *(byte *)Addr=Value;
  else
  {
#ifdef BIG_ENDIAN
    ((byte *)Addr)[0]=(byte)Value;
    ((byte *)Addr)[1]=(byte)(Value>>8);
    ((byte *)Addr)[2]=(byte)(Value>>16);
    ((byte *)Addr)[3]=(byte)(Value>>24);
#else
    *Addr=Value;
#endif
  }
}

#ifdef BIG_ENDIAN
  #define SET_VALUE(ByteMode,Addr,Value) SetValue(ByteMode,(uint *)Addr,Value)
#else
  #define SET_VALUE(ByteMode,Addr,Value) ((ByteMode) ? (*(byte *)(Addr)=(Value)):(*(uint *)(Addr)=(Value)))
#endif


void RarVM::SetValue(uint *Addr,uint Value)
{
  SetValue(false,Addr,Value);
}


inline uint* RarVM::GetOperand(VM_PreparedOperand *CmdOp)
{
  if (CmdOp->Type==VM_OPREGMEM)
    return((uint *)&Mem[(*CmdOp->Addr+CmdOp->Base)&VM_MEMMASK]);
  else
    return(CmdOp->Addr);
}


void RarVM::Execute(VM_PreparedProgram *Prg)
{
  memcpy(R,Prg->InitR,sizeof(Prg->InitR));
  unsigned int GlobalSize=Min(Prg->GlobalData.Size(),VM_GLOBALMEMSIZE);
  if (GlobalSize)
    memcpy(Mem+VM_GLOBALMEMADDR,&Prg->GlobalData[0],GlobalSize);
  unsigned int StaticSize=Min(Prg->StaticData.Size(),VM_GLOBALMEMSIZE-GlobalSize);
  if (StaticSize)
    memcpy(Mem+VM_GLOBALMEMADDR+GlobalSize,&Prg->StaticData[0],StaticSize);

  R[7]=VM_MEMSIZE;
  Flags=0;

  VM_PreparedCommand *PreparedCode=Prg->AltCmd ? Prg->AltCmd:&Prg->Cmd[0];
  if (!ExecuteCode(PreparedCode,Prg->CmdCount))
    PreparedCode[0].OpCode=VM_RET;
  uint NewBlockPos=GET_VALUE(false,&Mem[VM_GLOBALMEMADDR+0x20])&VM_MEMMASK;
  uint NewBlockSize=GET_VALUE(false,&Mem[VM_GLOBALMEMADDR+0x1c])&VM_MEMMASK;
  if (NewBlockPos+NewBlockSize>=VM_MEMSIZE)
    NewBlockPos=NewBlockSize=0;
  Prg->FilteredData=Mem+NewBlockPos;
  Prg->FilteredDataSize=NewBlockSize;

  Prg->GlobalData.Reset();
  uint DataSize=Min(GET_VALUE(false,(uint*)&Mem[VM_GLOBALMEMADDR+0x30]),VM_GLOBALMEMSIZE);
  if (DataSize!=0)
  {
    Prg->GlobalData.Add(DataSize+VM_FIXEDGLOBALSIZE);
    memcpy(&Prg->GlobalData[0],&Mem[VM_GLOBALMEMADDR],DataSize+VM_FIXEDGLOBALSIZE);
  }
}


#define SET_IP(IP)                      \
  if ((IP)>=CodeSize)                   \
    return(true);                       \
  if (--MaxOpCount<=0)                  \
    return(false);                      \
  Cmd=PreparedCode+(IP);

bool RarVM::ExecuteCode(VM_PreparedCommand *PreparedCode,int CodeSize)
{
  int MaxOpCount=25000000;
  VM_PreparedCommand *Cmd=PreparedCode;
  while (1)
  {
    uint *Op1=GetOperand(&Cmd->Op1);
    uint *Op2=GetOperand(&Cmd->Op2);
    switch(Cmd->OpCode)
    {
      case VM_MOV:
        SET_VALUE(Cmd->ByteMode,Op1,GET_VALUE(Cmd->ByteMode,Op2));
        break;
#ifdef VM_OPTIMIZE
      case VM_MOVB:
        SET_VALUE(true,Op1,GET_VALUE(true,Op2));
        break;
      case VM_MOVD:
        SET_VALUE(false,Op1,GET_VALUE(false,Op2));
        break;
#endif
      case VM_CMP:
        {
          uint Value1=GET_VALUE(Cmd->ByteMode,Op1);
          uint Result=Value1-GET_VALUE(Cmd->ByteMode,Op2);
          Flags=Result==0 ? VM_FZ:(Result>Value1)|(Result&VM_FS);
        }
        break;
#ifdef VM_OPTIMIZE
      case VM_CMPB:
        {
          uint Value1=GET_VALUE(true,Op1);
          uint Result=Value1-GET_VALUE(true,Op2);
          Flags=Result==0 ? VM_FZ:(Result>Value1)|(Result&VM_FS);
        }
        break;
      case VM_CMPD:
        {
          uint Value1=GET_VALUE(false,Op1);
          uint Result=Value1-GET_VALUE(false,Op2);
          Flags=Result==0 ? VM_FZ:(Result>Value1)|(Result&VM_FS);
        }
        break;
#endif
      case VM_ADD:
        {
          uint Value1=GET_VALUE(Cmd->ByteMode,Op1);
          uint Result=Value1+GET_VALUE(Cmd->ByteMode,Op2);
          Flags=Result==0 ? VM_FZ:(Result<Value1)|(Result&VM_FS);
          SET_VALUE(Cmd->ByteMode,Op1,Result);
        }
        break;
#ifdef VM_OPTIMIZE
      case VM_ADDB:
        SET_VALUE(true,Op1,GET_VALUE(true,Op1)+GET_VALUE(true,Op2));
        break;
      case VM_ADDD:
        SET_VALUE(false,Op1,GET_VALUE(false,Op1)+GET_VALUE(false,Op2));
        break;
#endif
      case VM_SUB:
        {
          uint Value1=GET_VALUE(Cmd->ByteMode,Op1);
          uint Result=Value1-GET_VALUE(Cmd->ByteMode,Op2);
          Flags=Result==0 ? VM_FZ:(Result>Value1)|(Result&VM_FS);
          SET_VALUE(Cmd->ByteMode,Op1,Result);
        }
        break;
#ifdef VM_OPTIMIZE
      case VM_SUBB:
        SET_VALUE(true,Op1,GET_VALUE(true,Op1)-GET_VALUE(true,Op2));
        break;
      case VM_SUBD:
        SET_VALUE(false,Op1,GET_VALUE(false,Op1)-GET_VALUE(false,Op2));
        break;
#endif
      case VM_JZ:
        if ((Flags & VM_FZ)!=0)
        {
          SET_IP(GET_VALUE(false,Op1));
          continue;
        }
        break;
      case VM_JNZ:
        if ((Flags & VM_FZ)==0)
        {
          SET_IP(GET_VALUE(false,Op1));
          continue;
        }
        break;
      case VM_INC:
        {
          uint Result=GET_VALUE(Cmd->ByteMode,Op1)+1;
          SET_VALUE(Cmd->ByteMode,Op1,Result);
          Flags=Result==0 ? VM_FZ:Result&VM_FS;
        }
        break;
#ifdef VM_OPTIMIZE
      case VM_INCB:
        SET_VALUE(true,Op1,GET_VALUE(true,Op1)+1);
        break;
      case VM_INCD:
        SET_VALUE(false,Op1,GET_VALUE(false,Op1)+1);
        break;
#endif
      case VM_DEC:
        {
          uint Result=GET_VALUE(Cmd->ByteMode,Op1)-1;
          SET_VALUE(Cmd->ByteMode,Op1,Result);
          Flags=Result==0 ? VM_FZ:Result&VM_FS;
        }
        break;
#ifdef VM_OPTIMIZE
      case VM_DECB:
        SET_VALUE(true,Op1,GET_VALUE(true,Op1)-1);
        break;
      case VM_DECD:
        SET_VALUE(false,Op1,GET_VALUE(false,Op1)-1);
        break;
#endif
      case VM_JMP:
        SET_IP(GET_VALUE(false,Op1));
        continue;
      case VM_XOR:
        {
          uint Result=GET_VALUE(Cmd->ByteMode,Op1)^GET_VALUE(Cmd->ByteMode,Op2);
          Flags=Result==0 ? VM_FZ:Result&VM_FS;
          SET_VALUE(Cmd->ByteMode,Op1,Result);
        }
        break;
      case VM_AND:
        {
          uint Result=GET_VALUE(Cmd->ByteMode,Op1)&GET_VALUE(Cmd->ByteMode,Op2);
          Flags=Result==0 ? VM_FZ:Result&VM_FS;
          SET_VALUE(Cmd->ByteMode,Op1,Result);
        }
        break;
      case VM_OR:
        {
          uint Result=GET_VALUE(Cmd->ByteMode,Op1)|GET_VALUE(Cmd->ByteMode,Op2);
          Flags=Result==0 ? VM_FZ:Result&VM_FS;
          SET_VALUE(Cmd->ByteMode,Op1,Result);
        }
        break;
      case VM_TEST:
        {
          uint Result=GET_VALUE(Cmd->ByteMode,Op1)&GET_VALUE(Cmd->ByteMode,Op2);
          Flags=Result==0 ? VM_FZ:Result&VM_FS;
        }
        break;
      case VM_JS:
        if ((Flags & VM_FS)!=0)
        {
          SET_IP(GET_VALUE(false,Op1));
          continue;
        }
        break;
      case VM_JNS:
        if ((Flags & VM_FS)==0)
        {
          SET_IP(GET_VALUE(false,Op1));
          continue;
        }
        break;
      case VM_JB:
        if ((Flags & VM_FC)!=0)
        {
          SET_IP(GET_VALUE(false,Op1));
          continue;
        }
        break;
      case VM_JBE:
        if ((Flags & (VM_FC|VM_FZ))!=0)
        {
          SET_IP(GET_VALUE(false,Op1));
          continue;
        }
        break;
      case VM_JA:
        if ((Flags & (VM_FC|VM_FZ))==0)
        {
          SET_IP(GET_VALUE(false,Op1));
          continue;
        }
        break;
      case VM_JAE:
        if ((Flags & VM_FC)==0)
        {
          SET_IP(GET_VALUE(false,Op1));
          continue;
        }
        break;
      case VM_PUSH:
        R[7]-=4;
        SET_VALUE(false,(uint *)&Mem[R[7]&VM_MEMMASK],GET_VALUE(false,Op1));
        break;
      case VM_POP:
        SET_VALUE(false,Op1,GET_VALUE(false,(uint *)&Mem[R[7] & VM_MEMMASK]));
        R[7]+=4;
        break;
      case VM_CALL:
        R[7]-=4;
        SET_VALUE(false,(uint *)&Mem[R[7]&VM_MEMMASK],Cmd-PreparedCode+1);
        SET_IP(GET_VALUE(false,Op1));
        continue;
      case VM_RET:
        if (R[7]>=VM_MEMSIZE)
          return(true);
        SET_IP(GET_VALUE(false,(uint *)&Mem[R[7] & VM_MEMMASK]));
        R[7]+=4;
        continue;
      case VM_NOT:
        SET_VALUE(Cmd->ByteMode,Op1,~GET_VALUE(Cmd->ByteMode,Op1));
        break;
      case VM_SHL:
        {
          uint Value1=GET_VALUE(Cmd->ByteMode,Op1);
          uint Value2=GET_VALUE(Cmd->ByteMode,Op2);
          uint Result=Value1<<Value2;
          Flags=(Result==0 ? VM_FZ:(Result&VM_FS))|((Value1<<(Value2-1))&0x80000000 ? VM_FC:0);
          SET_VALUE(Cmd->ByteMode,Op1,Result);
        }
        break;
      case VM_SHR:
        {
          uint Value1=GET_VALUE(Cmd->ByteMode,Op1);
          uint Value2=GET_VALUE(Cmd->ByteMode,Op2);
          uint Result=Value1>>Value2;
          Flags=(Result==0 ? VM_FZ:(Result&VM_FS))|((Value1>>(Value2-1))&VM_FC);
          SET_VALUE(Cmd->ByteMode,Op1,Result);
        }
        break;
      case VM_SAR:
        {
          uint Value1=GET_VALUE(Cmd->ByteMode,Op1);
          uint Value2=GET_VALUE(Cmd->ByteMode,Op2);
          uint Result=((int)Value1)>>Value2;
          Flags=(Result==0 ? VM_FZ:(Result&VM_FS))|((Value1>>(Value2-1))&VM_FC);
          SET_VALUE(Cmd->ByteMode,Op1,Result);
        }
        break;
      case VM_NEG:
        {
          uint Result=-GET_VALUE(Cmd->ByteMode,Op1);
          Flags=Result==0 ? VM_FZ:VM_FC|(Result&VM_FS);
          SET_VALUE(Cmd->ByteMode,Op1,Result);
        }
        break;
#ifdef VM_OPTIMIZE
      case VM_NEGB:
        SET_VALUE(true,Op1,-GET_VALUE(true,Op1));
        break;
      case VM_NEGD:
        SET_VALUE(false,Op1,-GET_VALUE(false,Op1));
        break;
#endif
      case VM_PUSHA:
        {
          const int RegCount=sizeof(R)/sizeof(R[0]);
          for (int I=0,SP=R[7]-4;I<RegCount;I++,SP-=4)
            SET_VALUE(false,(uint *)&Mem[SP & VM_MEMMASK],R[I]);
          R[7]-=RegCount*4;
        }
        break;
      case VM_POPA:
        {
          const int RegCount=sizeof(R)/sizeof(R[0]);
          for (uint I=0,SP=R[7];I<RegCount;I++,SP+=4)
            R[7-I]=GET_VALUE(false,(uint *)&Mem[SP & VM_MEMMASK]);
        }
        break;
      case VM_PUSHF:
        R[7]-=4;
        SET_VALUE(false,(uint *)&Mem[R[7]&VM_MEMMASK],Flags);
        break;
      case VM_POPF:
        Flags=GET_VALUE(false,(uint *)&Mem[R[7] & VM_MEMMASK]);
        R[7]+=4;
        break;
      case VM_MOVZX:
        SET_VALUE(false,Op1,GET_VALUE(true,Op2));
        break;
      case VM_MOVSX:
        SET_VALUE(false,Op1,(signed char)GET_VALUE(true,Op2));
        break;
      case VM_XCHG:
        {
          uint Value1=GET_VALUE(Cmd->ByteMode,Op1);
          SET_VALUE(Cmd->ByteMode,Op1,GET_VALUE(Cmd->ByteMode,Op2));
          SET_VALUE(Cmd->ByteMode,Op2,Value1);
        }
        break;
      case VM_MUL:
        {
          uint Result=GET_VALUE(Cmd->ByteMode,Op1)*GET_VALUE(Cmd->ByteMode,Op2);
          SET_VALUE(Cmd->ByteMode,Op1,Result);
        }
        break;
      case VM_DIV:
        {
          uint Divider=GET_VALUE(Cmd->ByteMode,Op2);
          if (Divider!=0)
          {
            uint Result=GET_VALUE(Cmd->ByteMode,Op1)/Divider;
            SET_VALUE(Cmd->ByteMode,Op1,Result);
          }
        }
        break;
      case VM_ADC:
        {
          uint Value1=GET_VALUE(Cmd->ByteMode,Op1);
          uint FC=(Flags&VM_FC);
          uint Result=Value1+GET_VALUE(Cmd->ByteMode,Op2)+FC;
          Flags=Result==0 ? VM_FZ:(Result<Value1 || Result==Value1 && FC)|(Result&VM_FS);
          SET_VALUE(Cmd->ByteMode,Op1,Result);
        }
        break;
      case VM_SBB:
        {
          uint Value1=GET_VALUE(Cmd->ByteMode,Op1);
          uint FC=(Flags&VM_FC);
          uint Result=Value1-GET_VALUE(Cmd->ByteMode,Op2)-FC;
          Flags=Result==0 ? VM_FZ:(Result>Value1 || Result==Value1 && FC)|(Result&VM_FS);
          SET_VALUE(Cmd->ByteMode,Op1,Result);
        }
        break;
#ifdef VM_STANDARDFILTERS
      case VM_STANDARD:
        ExecuteStandardFilter((VM_StandardFilters)Cmd->Op1.Data);
        break;
#endif
      case VM_PRINT:
#ifdef DEBUG
        PrintState(Cmd-PreparedCode);
#endif
        break;
    }
    Cmd++;
    --MaxOpCount;
  }
}


void RarVM::PrintState(uint IP)
{
#if defined(DEBUG) && !defined(GUI) && !defined(SILENT)
  mprintf("\n");
  for (int I=0;I<sizeof(R)/sizeof(R[0]);I++)
    mprintf("R%d=%08X\t%s",I,R[I],I==3 ? "\n":"");
  mprintf("\nIP=%08X\tFlags: C=%d S=%d",IP,(Flags & VM_FC)!=0,(Flags & VM_FS)!=0);
  mprintf("\n");
#endif
}


void RarVM::Prepare(byte *Code,int CodeSize,VM_PreparedProgram *Prg)
{
  InitBitInput();
  memcpy(InBuf,Code,Min(CodeSize,BitInput::MAX_SIZE));

  byte XorSum=0;
  for (int I=1;I<CodeSize;I++)
    XorSum^=Code[I];

  faddbits(8);

  Prg->CmdCount=0;
  if (XorSum==Code[0])
  {
#ifdef VM_STANDARDFILTERS
    VM_StandardFilters FilterType=IsStandardFilter(Code,CodeSize);
    if (FilterType!=VMSF_NONE)
    {
      Prg->Cmd.Add(1);
      VM_PreparedCommand *CurCmd=&Prg->Cmd[Prg->CmdCount++];
      CurCmd->OpCode=VM_STANDARD;
      CurCmd->Op1.Data=FilterType;
      CurCmd->Op1.Addr=&CurCmd->Op1.Data;
      CurCmd->Op2.Addr=&CurCmd->Op2.Data;
      CodeSize=0;
    }
#endif  
    uint DataFlag=fgetbits();
    faddbits(1);
    if (DataFlag&0x8000)
    {
      int DataSize=ReadData(*this)+1;
      for (int I=0;InAddr<CodeSize && I<DataSize;I++)
      {
        Prg->StaticData.Add(1);
        Prg->StaticData[I]=fgetbits()>>8;
        faddbits(8);
      }
    }
    while (InAddr<CodeSize)
    {
      Prg->Cmd.Add(1);
      VM_PreparedCommand *CurCmd=&Prg->Cmd[Prg->CmdCount];
      uint Data=fgetbits();
      if ((Data&0x8000)==0)
      {
        CurCmd->OpCode=(VM_Commands)(Data>>12);
        faddbits(4);
      }
      else
      {
        CurCmd->OpCode=(VM_Commands)((Data>>10)-24);
        faddbits(6);
      }
      if (VM_CmdFlags[CurCmd->OpCode] & VMCF_byteMODE)
      {
        CurCmd->ByteMode=fgetbits()>>15;
        faddbits(1);
      }
      else
        CurCmd->ByteMode=0;
      CurCmd->Op1.Type=CurCmd->Op2.Type=VM_OPNONE;
      int OpNum=(VM_CmdFlags[CurCmd->OpCode] & VMCF_OPMASK);
      CurCmd->Op1.Addr=&CurCmd->Op1.Data;
      CurCmd->Op2.Addr=&CurCmd->Op2.Data;
      if (OpNum>0)
      {
        DecodeArg(CurCmd->Op1,CurCmd->ByteMode);
        if (OpNum==2)
          DecodeArg(CurCmd->Op2,CurCmd->ByteMode);
        else
        {
          if (CurCmd->Op1.Type==VM_OPINT && (VM_CmdFlags[CurCmd->OpCode]&(VMCF_JUMP|VMCF_PROC)))
          {
            int Distance=CurCmd->Op1.Data;
            if (Distance>=256)
              Distance-=256;
            else
            {
              if (Distance>=136)
                Distance-=264;
              else
                if (Distance>=16)
                  Distance-=8;
                else
                  if (Distance>=8)
                    Distance-=16;
              Distance+=Prg->CmdCount;
            }
            CurCmd->Op1.Data=Distance;
          }
        }
      }
      Prg->CmdCount++;
    }
  }
  Prg->Cmd.Add(1);
  VM_PreparedCommand *CurCmd=&Prg->Cmd[Prg->CmdCount++];
  CurCmd->OpCode=VM_RET;
  CurCmd->Op1.Addr=&CurCmd->Op1.Data;
  CurCmd->Op2.Addr=&CurCmd->Op2.Data;

#ifdef VM_OPTIMIZE
  if (CodeSize!=0)
    Optimize(Prg);
#endif
}


void RarVM::DecodeArg(VM_PreparedOperand &Op,bool ByteMode)
{
  uint Data=fgetbits();
  if (Data & 0x8000)
  {
    Op.Type=VM_OPREG;
    Op.Data=(Data>>12)&7;
    Op.Addr=&R[Op.Data];
    faddbits(4);
  }
  else
    if ((Data & 0xc000)==0)
    {
      Op.Type=VM_OPINT;
      if (ByteMode)
      {
        Op.Data=(Data>>6) & 0xff;
        faddbits(10);
      }
      else
      {
        faddbits(2);
        Op.Data=ReadData(*this);
      }
      Op.Addr=&Op.Data;
    }
    else
    {
      Op.Type=VM_OPREGMEM;
      if ((Data & 0x2000)==0)
      {
        Op.Data=(Data>>10)&7;
        Op.Addr=&R[Op.Data];
        Op.Base=0;
        faddbits(6);
      }
      else
      {
        if ((Data & 0x1000)==0)
        {
          Op.Data=(Data>>9)&7;
          Op.Addr=&R[Op.Data];
          faddbits(7);
        }
        else
        {
          Op.Data=0;
          Op.Addr=&Op.Data;
          faddbits(4);
        }
        Op.Base=ReadData(*this);
      }
    }
}


uint RarVM::ReadData(BitInput &Inp)
{
  uint Data=Inp.fgetbits();
  switch(Data&0xc000)
  {
    case 0:
      Inp.faddbits(6);
      return((Data>>10)&0xf);
    case 0x4000:
      if ((Data&0x3c00)==0)
      {
        Data=0xffffff00|((Data>>2)&0xff);
        Inp.faddbits(14);
      }
      else
      {
        Data=(Data>>6)&0xff;
        Inp.faddbits(10);
      }
      return(Data);
    case 0x8000:
      Inp.faddbits(2);
      Data=Inp.fgetbits();
      Inp.faddbits(16);
      return(Data);
    default:
      Inp.faddbits(2);
      Data=(Inp.fgetbits()<<16);
      Inp.faddbits(16);
      Data|=Inp.fgetbits();
      Inp.faddbits(16);
      return(Data);
  }
}


void RarVM::SetMemory(unsigned int Pos,byte *Data,unsigned int DataSize)
{
  if (Pos<VM_MEMSIZE && Data!=Mem+Pos)
    memmove(Mem+Pos,Data,Min(DataSize,VM_MEMSIZE-Pos));
}


#ifdef VM_OPTIMIZE
void RarVM::Optimize(VM_PreparedProgram *Prg)
{
  VM_PreparedCommand *Code=&Prg->Cmd[0];
  int CodeSize=Prg->CmdCount;

  for (int I=0;I<CodeSize;I++)
  {
    VM_PreparedCommand *Cmd=Code+I;
    switch(Cmd->OpCode)
    {
      case VM_MOV:
        Cmd->OpCode=Cmd->ByteMode ? VM_MOVB:VM_MOVD;
        continue;
      case VM_CMP:
        Cmd->OpCode=Cmd->ByteMode ? VM_CMPB:VM_CMPD;
        continue;
    }
    if ((VM_CmdFlags[Cmd->OpCode] & VMCF_CHFLAGS)==0)
      continue;
    bool FlagsRequired=false;
    for (int J=I+1;J<CodeSize;J++)
    {
      int Flags=VM_CmdFlags[Code[J].OpCode];
      if (Flags & (VMCF_JUMP|VMCF_PROC|VMCF_USEFLAGS))
      {
        FlagsRequired=true;
        break;
      }
      if (Flags & VMCF_CHFLAGS)
        break;
    }
    if (FlagsRequired)
      continue;
    switch(Cmd->OpCode)
    {
      case VM_ADD:
        Cmd->OpCode=Cmd->ByteMode ? VM_ADDB:VM_ADDD;
        continue;
      case VM_SUB:
        Cmd->OpCode=Cmd->ByteMode ? VM_SUBB:VM_SUBD;
        continue;
      case VM_INC:
        Cmd->OpCode=Cmd->ByteMode ? VM_INCB:VM_INCD;
        continue;
      case VM_DEC:
        Cmd->OpCode=Cmd->ByteMode ? VM_DECB:VM_DECD;
        continue;
      case VM_NEG:
        Cmd->OpCode=Cmd->ByteMode ? VM_NEGB:VM_NEGD;
        continue;
    }
  }
}
#endif


#ifdef VM_STANDARDFILTERS
VM_StandardFilters RarVM::IsStandardFilter(byte *Code,int CodeSize)
{
  struct StandardFilterSignature
  {
    int Length;
    uint CRC;
    VM_StandardFilters Type;
  } StdList[]={
    53, 0xad576887, VMSF_E8,
    57, 0x3cd7e57e, VMSF_E8E9,
   120, 0x3769893f, VMSF_ITANIUM,
    29, 0x0e06077d, VMSF_DELTA,
   149, 0x1c2c5dc8, VMSF_RGB,
   216, 0xbc85e701, VMSF_AUDIO,
    40, 0x46b9c560, VMSF_UPCASE
  };
  uint CodeCRC=CRC(0xffffffff,Code,CodeSize)^0xffffffff;
  for (int I=0;I<sizeof(StdList)/sizeof(StdList[0]);I++)
    if (StdList[I].CRC==CodeCRC && StdList[I].Length==CodeSize)
      return(StdList[I].Type);
  return(VMSF_NONE);
}


void RarVM::ExecuteStandardFilter(VM_StandardFilters FilterType)
{
  switch(FilterType)
  {
    case VMSF_E8:
    case VMSF_E8E9:
      {
        byte *Data=Mem;
        int DataSize=R[4];
        uint FileOffset=R[6];

        if (DataSize>=VM_GLOBALMEMADDR)
          break;

        const int FileSize=0x1000000;
        byte CmpByte2=FilterType==VMSF_E8E9 ? 0xe9:0xe8;
        for (uint CurPos=0;CurPos<DataSize-4;)
        {
          byte CurByte=*(Data++);
          CurPos++;
          if (CurByte==0xe8 || CurByte==CmpByte2)
          {
            long Offset=CurPos+FileOffset;
            long Addr=GET_VALUE(false,Data);
            if (Addr<0)
            {
              if (Addr+Offset>=0)
                SET_VALUE(false,Data,Addr+FileSize);
            }
            else 
              if (Addr<FileSize)
                SET_VALUE(false,Data,Addr-Offset);
            Data+=4;
            CurPos+=4;
          }
        }
      }
      break;
    case VMSF_ITANIUM:
      {
        byte *Data=Mem;
        int DataSize=R[4];
        uint FileOffset=R[6];

        if (DataSize>=VM_GLOBALMEMADDR)
          break;

        uint CurPos=0;

        FileOffset>>=4;

        while (CurPos<DataSize-21)
        {
          int Byte=(Data[0]&0x1f)-0x10;
          if (Byte>=0)
          {
            static byte Masks[16]={4,4,6,6,0,0,7,7,4,4,0,0,4,4,0,0};
            byte CmdMask=Masks[Byte];
            if (CmdMask!=0)
              for (int I=0;I<=2;I++)
                if (CmdMask & (1<<I))
                {
                  int StartPos=I*41+5;
                  int OpType=FilterItanium_GetBits(Data,StartPos+37,4);
                  if (OpType==5)
                  {
                    int Offset=FilterItanium_GetBits(Data,StartPos+13,20);
                    FilterItanium_SetBits(Data,(Offset-FileOffset)&0xfffff,StartPos+13,20);
                  }
                }
          }
          Data+=16;
          CurPos+=16;
          FileOffset++;
        }
      }
      break;
    case VMSF_DELTA:
      {
        int DataSize=R[4],Channels=R[0],SrcPos=0,Border=DataSize*2;
        SET_VALUE(false,&Mem[VM_GLOBALMEMADDR+0x20],DataSize);
        if (DataSize>=VM_GLOBALMEMADDR/2)
          break;
        for (int CurChannel=0;CurChannel<Channels;CurChannel++)
        {
          byte PrevByte=0;
          for (int DestPos=DataSize+CurChannel;DestPos<Border;DestPos+=Channels)
            Mem[DestPos]=(PrevByte-=Mem[SrcPos++]);
        }
      }
      break;
    case VMSF_RGB:
      {
        int DataSize=R[4],Width=R[0]-3,PosR=R[1];
        byte *SrcData=Mem,*DestData=SrcData+DataSize;
        const int Channels=3;
        SET_VALUE(false,&Mem[VM_GLOBALMEMADDR+0x20],DataSize);
        if (DataSize>=VM_GLOBALMEMADDR/2)
          break;
        for (int CurChannel=0;CurChannel<Channels;CurChannel++)
        {
          unsigned int PrevByte=0;

          for (int I=CurChannel;I<DataSize;I+=Channels)
          {
            unsigned int Predicted;
            int UpperPos=I-Width;
            if (UpperPos>=3)
            {
              byte *UpperData=DestData+UpperPos;
              unsigned int UpperByte=*UpperData;
              unsigned int UpperLeftByte=*(UpperData-3);
              Predicted=PrevByte+UpperByte-UpperLeftByte;
              int pa=abs((int)(Predicted-PrevByte));
              int pb=abs((int)(Predicted-UpperByte));
              int pc=abs((int)(Predicted-UpperLeftByte));
              if (pa<=pb && pa<=pc)
                Predicted=PrevByte;
              else
                if (pb<=pc)
                  Predicted=UpperByte;
                else
                  Predicted=UpperLeftByte;
            }
            else
              Predicted=PrevByte;
            DestData[I]=PrevByte=(byte)(Predicted-*(SrcData++));
          }
        }
        for (int I=PosR,Border=DataSize-2;I<Border;I+=3)
        {
          byte G=DestData[I+1];
          DestData[I]+=G;
          DestData[I+2]+=G;
        }
      }
      break;
    case VMSF_AUDIO:
      {
        int DataSize=R[4],Channels=R[0];
        byte *SrcData=Mem,*DestData=SrcData+DataSize;
        SET_VALUE(false,&Mem[VM_GLOBALMEMADDR+0x20],DataSize);
        if (DataSize>=VM_GLOBALMEMADDR/2)
          break;
        for (int CurChannel=0;CurChannel<Channels;CurChannel++)
        {
          unsigned int PrevByte=0,PrevDelta=0,Dif[7];
          int D1=0,D2=0,D3;
          int K1=0,K2=0,K3=0;
          memset(Dif,0,sizeof(Dif));

          for (int I=CurChannel,ByteCount=0;I<DataSize;I+=Channels,ByteCount++)
          {
            D3=D2;
            D2=PrevDelta-D1;
            D1=PrevDelta;

            unsigned int Predicted=8*PrevByte+K1*D1+K2*D2+K3*D3;
            Predicted=(Predicted>>3) & 0xff;

            unsigned int CurByte=*(SrcData++);

            Predicted-=CurByte;
            DestData[I]=Predicted;
            PrevDelta=(signed char)(Predicted-PrevByte);
            PrevByte=Predicted;

            int D=((signed char)CurByte)<<3;

            Dif[0]+=abs(D);
            Dif[1]+=abs(D-D1);
            Dif[2]+=abs(D+D1);
            Dif[3]+=abs(D-D2);
            Dif[4]+=abs(D+D2);
            Dif[5]+=abs(D-D3);
            Dif[6]+=abs(D+D3);

            if ((ByteCount & 0x1f)==0)
            {
              unsigned int MinDif=Dif[0],NumMinDif=0;
              Dif[0]=0;
              for (int J=1;J<sizeof(Dif)/sizeof(Dif[0]);J++)
              {
                if (Dif[J]<MinDif)
                {
                  MinDif=Dif[J];
                  NumMinDif=J;
                }
                Dif[J]=0;
              }
              switch(NumMinDif)
              {
                case 1: if (K1>=-16) K1--; break;
                case 2: if (K1 < 16) K1++; break;
                case 3: if (K2>=-16) K2--; break;
                case 4: if (K2 < 16) K2++; break;
                case 5: if (K3>=-16) K3--; break;
                case 6: if (K3 < 16) K3++; break;
              }
            }
          }
        }
      }
      break;
    case VMSF_UPCASE:
      {
        int DataSize=R[4],SrcPos=0,DestPos=DataSize;
        if (DataSize>=VM_GLOBALMEMADDR/2)
          break;
        while (SrcPos<DataSize)
        {
          byte CurByte=Mem[SrcPos++];
          if (CurByte==2 && (CurByte=Mem[SrcPos++])!=2)
            CurByte-=32;
          Mem[DestPos++]=CurByte;
        }
        SET_VALUE(false,&Mem[VM_GLOBALMEMADDR+0x1c],DestPos-DataSize);
        SET_VALUE(false,&Mem[VM_GLOBALMEMADDR+0x20],DataSize);
      }
      break;
  }
}


unsigned int RarVM::FilterItanium_GetBits(byte *Data,int BitPos,int BitCount)
{
  int InAddr=BitPos/8;
  int InBit=BitPos&7;
  unsigned int BitField=(uint)Data[InAddr++];
  BitField|=(uint)Data[InAddr++] << 8;
  BitField|=(uint)Data[InAddr++] << 16;
  BitField|=(uint)Data[InAddr] << 24;
  BitField >>= InBit;
  return(BitField & (0xffffffff>>(32-BitCount)));
}


void RarVM::FilterItanium_SetBits(byte *Data,unsigned int BitField,int BitPos,
                                  int BitCount)
{
  int InAddr=BitPos/8;
  int InBit=BitPos&7;
  unsigned int AndMask=0xffffffff>>(32-BitCount);
  AndMask=~(AndMask<<InBit);

  BitField<<=InBit;

  for (int I=0;I<4;I++)
  {
    Data[InAddr+I]&=AndMask;
    Data[InAddr+I]|=BitField;
    AndMask=(AndMask>>8)|0xff000000;
    BitField>>=8;
  }
}
#endif
