示例#1
0
 public ASMDecoderResult DecodeASM(IEnumerable <byte> bytes, uint pc, bool littleEndian = true, bool useRegAliases = false)
 {
     uint[] uintArray = ASMValueHelper.GetUintArrayFromBytes(bytes, littleEndian);
     return(DecodeASM(uintArray, pc, useRegAliases));
 }
        public byte[] UpdateBlockReferences(byte[] bytes, uint pc, bool littleEndian, IEnumerable <BlockMove> blockMoves)
        {
            int byteCount = bytes.Length;

            if (byteCount < 4)
            {
                return(bytes);
            }

            byte[] resultBytes = new byte[byteCount];
            int    startIndex  = 0;

            byte[] asmBytes = bytes;

            if (byteCount > 4)
            {
                uint offsetBytes = pc % 4;
                if (offsetBytes != 0)
                {
                    uint skipBytes = 4 - offsetBytes;
                    pc          = pc + skipBytes;
                    startIndex += (int)skipBytes;
                    int    length   = (int)(bytes.Length - skipBytes);
                    byte[] newBytes = new byte[length];
                    Array.Copy(bytes, skipBytes, newBytes, 0, length);
                    Array.Copy(bytes, 0, resultBytes, 0, startIndex);
                    asmBytes = newBytes;
                }
            }

            uint[] instructions = ASMValueHelper.GetUintArrayFromBytes(asmBytes, littleEndian);

            int numInstructions = instructions.Length;

            uint[] newInstructions = new uint[numInstructions];
            uint[] regLuiValues    = new uint[32];
            int[]  regLuiIndexes   = new int[32];

            for (int regNum = 0; regNum < 32; regNum++)
            {
                regLuiIndexes[regNum] = -1;
            }

            for (int index = 0; index < numInstructions; index++)
            {
                uint uBinaryLine    = instructions[index];
                uint opcode         = (uBinaryLine >> 26);
                uint newInstruction = uBinaryLine;

                // Is unconditional jump literal command J or JAL
                if ((opcode & 0x3E) == 0x02)  // ((opcode & 0b111110) == 0b000010)
                {
                    uint jumpAddress = (((uBinaryLine & 0x03FFFFFFU) << 2) | (pc & 0xF0000000U));

                    foreach (BlockMove blockMove in blockMoves)
                    {
                        if ((jumpAddress >= blockMove.Location) && (jumpAddress < blockMove.EndLocation))
                        {
                            uint newJumpAddress = (uint)(jumpAddress + blockMove.Offset);
                            newInstruction = (opcode << 26) | ((newJumpAddress >> 2) & 0x03FFFFFFU);
                        }
                    }
                }

                // Is Load Upper Immediate (LUI)
                EncodingFormat encFormat = Decoder.FormatHelper.FindFormatByBinary(uBinaryLine);
                if (encFormat.Command == "lui")
                {
                    int  regNum    = (int)(uBinaryLine >> encFormat.RegisterPositions[0] & encFormat.RegisterIncludeMasks[0]);
                    uint immediate = (uint)(uBinaryLine >> encFormat.ImmediatePositions[0] & encFormat.ImmediateIncludeMasks[0]);
                    regLuiValues[regNum]  = immediate;
                    regLuiIndexes[regNum] = index;
                }

                // Is Load or Store command, or ADDI, ADDIU, or ORI
                if (IsLoadCommand(encFormat.Command) || IsStoreCommand(encFormat.Command) || ((encFormat.Command == "addi") || (encFormat.Command == "addiu") || (encFormat.Command == "ori")))
                {
                    int regNum = (int)(uBinaryLine >> encFormat.RegisterPositions[1] & encFormat.RegisterIncludeMasks[1]);

                    if (regLuiIndexes[regNum] >= 0)
                    {
                        short offset        = ASMValueHelper.UnsignedShortToSignedShort((ushort)(uBinaryLine & 0xffff));
                        uint  targetAddress = (uint)((regLuiValues[regNum] << 16) + offset) | (0x80000000U);

                        foreach (BlockMove blockMove in blockMoves)
                        {
                            if ((targetAddress >= blockMove.Location) && (targetAddress < blockMove.EndLocation))
                            {
                                uint   newTargetAddress = (uint)(targetAddress + blockMove.Offset);
                                uint   newLuiValue      = (ushort)(newTargetAddress >> 16);
                                ushort newOffset        = (ushort)(newTargetAddress & 0xffff);

                                if (encFormat.Command != "ori")
                                {
                                    newLuiValue += (uint)((newOffset >= 0x8000) ? 1 : 0);
                                }

                                newInstruction = ((uBinaryLine & 0xFFFF0000U) | newOffset);

                                //  Modify the LUI if necessary
                                if (newLuiValue != regLuiValues[regNum])
                                {
                                    uint newLuiInstruction = (newInstructions[regLuiIndexes[regNum]] & 0xFFFF0000U) | newLuiValue;
                                    newInstructions[regLuiIndexes[regNum]] = newLuiInstruction;
                                    byte[] newLuiInstructionBytes = ASMValueHelper.ConvertUIntToBytes(newLuiInstruction, littleEndian);
                                    Array.Copy(newLuiInstructionBytes, 0, resultBytes, (regLuiIndexes[regNum] * 4) + startIndex, 4);
                                }
                            }
                        }
                    }
                }

                newInstructions[index] = newInstruction;
                byte[] newBytes = ASMValueHelper.ConvertUIntToBytes(newInstruction, littleEndian);
                Array.Copy(newBytes, 0, resultBytes, (index * 4) + startIndex, 4);
            }

            for (int index = (numInstructions * 4) + startIndex; index < byteCount; index++)
            {
                resultBytes[index] = bytes[index];
            }

            return(resultBytes);
        }