#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];
}

/*********************************************************************
 IS_VM_MEM macro checks if address belongs to VM memory pool (Mem).
 Only Mem data are always low endian regardless of machine architecture,
 so we need to convert them to native format when reading or writing.
 VM registers have endianness of host machine.
**********************************************************************/
#define IS_VM_MEM(a) (((byte*)a)>=Mem && ((byte*)a)<Mem+VM_MEMSIZE)

inline uint RarVM::GetValue(bool ByteMode,uint *Addr)
{
  if (ByteMode)
  {
#ifdef BIG_ENDIAN
    if (IS_VM_MEM(Addr))
      return(*(byte *)Addr);
    else
      return(*Addr & 0xff);
#else
    return(*(byte *)Addr);
#endif
  }
  else
  {
#if defined(BIG_ENDIAN) || !defined(ALLOW_NOT_ALIGNED_INT)
    if (IS_VM_MEM(Addr))
    {
      byte *B=(byte *)Addr;
      return UINT32((uint)B[0]|((uint)B[1]<<8)|((uint)B[2]<<16)|((uint)B[3]<<24));
    }
    else
      return UINT32(*Addr);
#else
    return UINT32(*Addr);
#endif
  }
}

#if defined(BIG_ENDIAN) || !defined(ALLOW_NOT_ALIGNED_INT)
  #define GET_VALUE(ByteMode,Addr) GetValue(ByteMode,(uint *)Addr)
#else
  #define GET_VALUE(ByteMode,Addr) ((ByteMode) ? (*(byte *)(Addr)):UINT32(*(uint *)(Addr)))
#endif


inline void RarVM::SetValue(bool ByteMode,uint *Addr,uint Value)
{
  if (ByteMode)
  {
#ifdef BIG_ENDIAN
    if (IS_VM_MEM(Addr))
      *(byte *)Addr=Value;
    else
      *Addr=(*Addr & ~0xff)|(Value & 0xff);
#else
    *(byte *)Addr=Value;
#endif
  }
  else
  {
#if defined(BIG_ENDIAN) || !defined(ALLOW_NOT_ALIGNED_INT) || !defined(PRESENT_INT32)
    if (IS_VM_MEM(Addr))
    {
      ((byte *)Addr)[0]=(byte)Value;
      ((byte *)Addr)[1]=(byte)(Value>>8);
      ((byte *)Addr)[2]=(byte)(Value>>16);
      ((byte *)Addr)[3]=(byte)(Value>>24);
    }
    else
      *(uint *)Addr=Value;
#else
    *(uint32 *)Addr=Value;
#endif
  }
}

#if defined(BIG_ENDIAN) || !defined(ALLOW_NOT_ALIGNED_INT) || !defined(PRESENT_INT32)
  #define SET_VALUE(ByteMode,Addr,Value) SetValue(ByteMode,(uint *)Addr,Value)
#else
  #define SET_VALUE(ByteMode,Addr,Value) ((ByteMode) ? (*(byte *)(Addr)=(Value)):(*(uint32 *)(Addr)=((uint32)(Value))))
#endif


void RarVM::SetLowEndianValue(uint *Addr,uint Value)
{
#if defined(BIG_ENDIAN) || !defined(ALLOW_NOT_ALIGNED_INT) || !defined(PRESENT_INT32)
  ((byte *)Addr)[0]=(byte)Value;
  ((byte *)Addr)[1]=(byte)(Value>>8);
  ((byte *)Addr)[2]=(byte)(Value>>16);
  ((byte *)Addr)[3]=(byte)(Value>>24);
#else
  *(uint32 *)Addr=Value;
#endif
}


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-VM_FIXEDGLOBALSIZE);
  if (DataSize!=0)
  {
    Prg->GlobalData.Add(DataSize+VM_FIXEDGLOBALSIZE);
    memcpy(&Prg->GlobalData[0],&Mem[VM_GLOBALMEMADDR],DataSize+VM_FIXEDGLOBALSIZE);
  }
}


/*
Note:
  Due to performance considerations RAR VM may set VM_FS, VM_FC, VM_FZ
  incorrectly for byte operands. These flags are always valid only
  for 32-bit operands. Check implementation of concrete VM command
  to see if it sets flags right.
*/

#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)
  {
#ifndef NORARVM
    uint *Op1=GetOperand(&Cmd->Op1);
    uint *Op2=GetOperand(&Cmd->Op2);
#endif
    switch(Cmd->OpCode)
    {
#ifndef NORARVM
      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=UINT32(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=UINT32(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=UINT32(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=UINT32(Value1+GET_VALUE(Cmd->ByteMode,Op2));
          if (Cmd->ByteMode)
          {
            Result&=0xff;
            Flags=(Result<Value1)|(Result==0 ? VM_FZ:((Result&0x80) ? VM_FS:0));
          }
          else
            Flags=(Result<Value1)|(Result==0 ? VM_FZ:(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=UINT32(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=UINT32(GET_VALUE(Cmd->ByteMode,Op1)+1);
          if (Cmd->ByteMode)
            Result&=0xff;
          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=UINT32(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=UINT32(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=UINT32(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=UINT32(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=UINT32(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_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=UINT32(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=UINT32(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=UINT32(((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=UINT32(-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=UINT32(Value1+GET_VALUE(Cmd->ByteMode,Op2)+FC);
          if (Cmd->ByteMode)
            Result&=0xff;
          Flags=(Result<Value1 || Result==Value1 && FC)|(Result==0 ? VM_FZ:(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=UINT32(Value1-GET_VALUE(Cmd->ByteMode,Op2)-FC);
          if (Cmd->ByteMode)
            Result&=0xff;
          Flags=(Result>Value1 || Result==Value1 && FC)|(Result==0 ? VM_FZ:(Result&VM_FS));
          SET_VALUE(Cmd->ByteMode,Op1,Result);
        }
        break;
#endif  // for #ifndef NORARVM
      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;
#ifdef VM_STANDARDFILTERS
      case VM_STANDARD:
        ExecuteStandardFilter((VM_StandardFilters)Cmd->Op1.Data);
        break;
#endif
      case VM_PRINT:
        break;
    }
    Cmd++;
    --MaxOpCount;
  }
}




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;
      CurCmd->Op1.Type=CurCmd->Op2.Type=VM_OPNONE;
      CodeSize=0;
    }
#endif  
    uint DataFlag=fgetbits();
    faddbits(1);

/* Read static data contained in DB operators. This data cannot be changed,
   it is a part of VM code, not a filter parameter.
*/
    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->Op2.Addr=NULL;
      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;
  CurCmd->Op1.Type=CurCmd->Op2.Type=VM_OPNONE;

  for (int I=0;I<Prg->CmdCount;I++)
  {
    VM_PreparedCommand *Cmd=&Prg->Cmd[I];
    if (Cmd->Op1.Addr==NULL)
      Cmd->Op1.Addr=&Cmd->Op1.Data;
    if (Cmd->Op2.Addr==NULL)
      Cmd->Op2.Addr=&Cmd->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);
      }
    }
    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;
          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 || DataSize<4)
          break;

        const int FileSize=0x1000000;
        byte CmpByte2=FilterType==VMSF_E8E9 ? 0xe9:0xe8;
        for (int CurPos=0;CurPos<DataSize-4;)
        {
          byte CurByte=*(Data++);
          CurPos++;
          if (CurByte==0xe8 || CurByte==CmpByte2)
          {
#ifdef PRESENT_INT32
            sint32 Offset=CurPos+FileOffset;
            sint32 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);
#else
            long Offset=CurPos+FileOffset;
            long Addr=GET_VALUE(false,Data);
            if ((Addr & 0x80000000)!=0)
            {
              if (((Addr+Offset) & 0x80000000)==0)
                SET_VALUE(false,Data,Addr+FileSize);
            }
            else 
              if (((Addr-FileSize) & 0x80000000)!=0)
                SET_VALUE(false,Data,Addr-Offset);
#endif
            Data+=4;
            CurPos+=4;
          }
        }
      }
      break;
    case VMSF_ITANIUM:
      {
        byte *Data=Mem;
        int DataSize=R[4];
        uint FileOffset=R[6];

        if (DataSize>=VM_GLOBALMEMADDR || DataSize<21)
          break;

        int 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;

// bytes from same channels are grouped to continual data blocks,
// so we need to place them back to their interleaving positions

        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 || PosR<0)
          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
