public static void GenerateIncomingCalls(IEnumerable <ProgramLine> programLines, MemoryMap memoryMap)
{
foreach (ProgramLine instructionLine in programLines)
{
if (instructionLine.OutgoingCall != null)
{
// Find the memory description of the call target address
int targetAddress = instructionLine.OutgoingCall.Address;
MemoryCellDescription memDescription = memoryMap.MemoryCellDescriptions[targetAddress];
// This description should be a instruction line starting at the same address
if (memDescription == null || memDescription.Type != MemoryDescriptionType.ProgramLine)
{
throw new Exception("Outgoing call at address " + targetAddress + " points to an unknown area in memory");
}
ProgramLine targetLine = (ProgramLine)memDescription.Description;
if (targetLine.Type != ProgramLineType.OpCodeInstruction || targetLine.LineAddress != targetAddress)
{
throw new Exception("Outgoing call from program line " + instructionLine.Text + " at address " + instructionLine.LineAddress + " points in the middle of the instruction " + targetLine.Text + " starting at address " + targetLine.LineAddress + " in memory");
}
else
{
// Connect the source and the target
instructionLine.OutgoingCall.Line = targetLine;
if (targetLine.IncomingCalls == null)
{
targetLine.IncomingCalls = new List <CallSource>();
}
targetLine.IncomingCalls.Add(instructionLine.OutgoingCall.Source);
}
}
}
}
public MemoryMap(int size)
{
MemoryCells = new byte[size];
MemoryCellDescriptions = new MemoryCellDescription[size];
Programs = new List <Program>();
}
private static void CompileInstructionLine(Program program, MemoryMap memoryMap, ref int address, IList<Operand> operands, ProgramLine programLine)
{
if (!String.IsNullOrEmpty(programLine.Label))
{
string label = programLine.Label;
if (!program.Variables.ContainsKey(label))
{
program.Variables.Add(label, new LabelAddress(address));
}
}
// Find instruction code and instruction type
string instructionText = GenerateInstructionText(programLine);
InstructionCode instructionCode = null;
if (!Z80OpCodes.Dictionary.TryGetValue(instructionText, out instructionCode))
{
throw new Exception(String.Format("Line {0} : invalid instruction type {1}", programLine.LineNumber, instructionText));
}
InstructionType instructionType = Z80InstructionTypes.Table[instructionCode.InstructionTypeIndex];
// Register binary representation of program line
programLine.InstructionCode = instructionCode;
programLine.InstructionType = instructionType;
MemoryCellDescription programLineDescription = new MemoryCellDescription(MemoryDescriptionType.ProgramLine, programLine);
// One or two byte opcodes
if (instructionCode.OpCodeByteCount <= 2)
{
// Optional one byte prefix
if (instructionCode.Prefix != null)
{
memoryMap.MemoryCellDescriptions[address] = programLineDescription;
memoryMap.MemoryCells[address++] = instructionCode.Prefix[0];
}
// Opcode
memoryMap.MemoryCellDescriptions[address] = programLineDescription;
memoryMap.MemoryCells[address++] = instructionCode.OpCode;
// Parameters
AddressingMode? paramType1 = instructionType.Param1Type;
if (paramType1.HasValue)
{
InstructionLineParam lineParam1 = programLine.OpCodeParameters[0];
AddOperandForLineParam(ref address, operands, programLine, paramType1, lineParam1);
}
AddressingMode? paramType2 = instructionType.Param2Type;
if (paramType2.HasValue)
{
InstructionLineParam lineParam2 = programLine.OpCodeParameters[1];
AddOperandForLineParam(ref address, operands, programLine, paramType2, lineParam2);
}
}
// Four bytes opcodes
else
{
// Two bytes prefix
memoryMap.MemoryCellDescriptions[address] = programLineDescription;
memoryMap.MemoryCells[address++] = instructionCode.Prefix[0];
memoryMap.MemoryCellDescriptions[address] = programLineDescription;
memoryMap.MemoryCells[address++] = instructionCode.Prefix[1];
// Displacement
AddressingMode? paramType1 = instructionType.Param1Type;
if (paramType1.HasValue)
{
InstructionLineParam lineParam1 = programLine.OpCodeParameters[0];
AddOperandForLineParam(ref address, operands, programLine, paramType1, lineParam1);
}
AddressingMode? paramType2 = instructionType.Param2Type;
if (paramType2.HasValue)
{
InstructionLineParam lineParam2 = programLine.OpCodeParameters[1];
AddOperandForLineParam(ref address, operands, programLine, paramType2, lineParam2);
}
// Opcode
memoryMap.MemoryCellDescriptions[address] = programLineDescription;
memoryMap.MemoryCells[address++] = instructionCode.OpCode;
}
}
private static bool CompileDirectiveLine(Program program, MemoryMap memoryMap, ref int address, IList<Operand> operands, ProgramLine programLine)
{
switch (programLine.DirectiveName)
{
case "EQU":
// label EQU nn : this directive is used to assign a value to a label.
if (String.IsNullOrEmpty(programLine.Label))
{
throw new Exception(String.Format("Line {0} : EQU directive needs a label", programLine.LineNumber));
}
else if (programLine.DirectiveParameters.Count != 1)
{
throw new Exception(String.Format("Line {0} : EQU directive needs exactly one parameter", programLine.LineNumber));
}
else
{
DirectiveLineParam param = programLine.DirectiveParameters[0];
string label = programLine.Label;
if (program.Variables.ContainsKey(label))
{
throw new Exception(String.Format("Line {0} : EQU directive - this label can not be defined twice", programLine.LineNumber));
}
program.Variables.Add(label, param.NumberExpression);
}
break;
case "DEFL":
// label DEFL nn : this directive also assigns a value nn to a label,
// but may be repeated whithin the program with different values for
// the same label, whereas EQU may be used only once.
// ==> Symbol table is much more complicated to handle in incremental parsing scenarios if it does not contain constants only
throw new Exception(String.Format("Line {0} : DEFL directive is not supported", programLine.LineNumber));
case "ORG":
// ORG nn : this directive will set the address counter to the value nn.
// In other words, the first executable instruction encountered after
// this directive will reside at the value nn. It can be used to locate
// different segments of a program at different memory locations.
if (!String.IsNullOrEmpty(programLine.Label))
{
throw new Exception(String.Format("Line {0} : ORG directive does not allow a label", programLine.LineNumber));
}
else if (programLine.DirectiveParameters.Count != 1)
{
throw new Exception(String.Format("Line {0} : ORG directive needs exactly one parameter", programLine.LineNumber));
}
else
{
DirectiveLineParam param = programLine.DirectiveParameters[0];
address = param.NumberExpression.GetValue(program.Variables, programLine);
}
break;
case "DEFS":
// DEFS nn : reserves a bloc of memory size nn bytes, starting at the
// current value of the reference counter.
case "RESERVE":
// label RESERVE nn : using the RESERVE pseudo-operation, you assign a
// name to the memory area and declare the number of locations to be assigned.
if (String.IsNullOrEmpty(programLine.Label))
{
string label = programLine.Label;
program.Variables.Add(label, new LabelAddress(address));
}
if (programLine.DirectiveParameters.Count != 1)
{
throw new Exception(String.Format("Line {0} : DEFS or RESERVE directive needs exactly one parameter", programLine.LineNumber));
}
else
{
string label = programLine.Label;
program.Variables.Add(label, new NumberOperand(address));
DirectiveLineParam param = programLine.DirectiveParameters[0];
int increment = param.NumberExpression.GetValue(program.Variables, programLine);
address += increment;
}
break;
case "DEFB":
// DEFB n,n,... : this directive assigns eight-bit contents to a byte
// residing at the current reference counter.
// DEFB 'S',... : assigns the ASCII value of 'S' to the byte.
if (!String.IsNullOrEmpty(programLine.Label))
{
string label = programLine.Label;
program.Variables.Add(label, new LabelAddress(address));
}
if (programLine.DirectiveParameters == null)
{
throw new Exception(String.Format("Line {0} : DEFB directive needs at least one parameter", programLine.LineNumber));
}
else
{
foreach (DirectiveLineParam param in programLine.DirectiveParameters)
{
Operand operand = new Operand() { Type = OperandType.Unsigned8, Address = address, Expression = param.NumberExpression, Line = programLine };
address += 1;
operands.Add(operand);
}
}
break;
case "DEFW":
// DEFW nn,nn,... : this assigns the value nn to the two-byte word residing at
// the current reference counter and the following location.
if (!String.IsNullOrEmpty(programLine.Label))
{
string label = programLine.Label;
program.Variables.Add(label, new LabelAddress(address));
}
if (programLine.DirectiveParameters == null)
{
throw new Exception(String.Format("Line {0} : DEFW directive at least one parameter", programLine.LineNumber));
}
else
{
foreach (DirectiveLineParam param in programLine.DirectiveParameters)
{
Operand operand = new Operand() { Type = OperandType.Unsigned16, Address = address, Expression = param.NumberExpression, Line = programLine };
address += 2;
operands.Add(operand);
}
}
break;
case "DEFM":
// DEFM "S" : stores into memory the string "S" starting at the current
// reference counter. It must less than 63 in length.
if (!String.IsNullOrEmpty(programLine.Label))
{
string label = programLine.Label;
program.Variables.Add(label, new LabelAddress(address));
}
if (programLine.DirectiveParameters.Count != 1)
{
throw new Exception(String.Format("Line {0} : DEFM directive needs exactly one parameter", programLine.LineNumber));
}
else
{
DirectiveLineParam param = programLine.DirectiveParameters[0];
string stringValue = param.StringValue;
MemoryCellDescription programLineDescription = new MemoryCellDescription(MemoryDescriptionType.ProgramLine, programLine);
foreach (char chr in stringValue.ToCharArray())
{
memoryMap.MemoryCellDescriptions[address] = programLineDescription;
memoryMap.MemoryCells[address] = (byte)chr;
address += 1;
}
}
break;
case "DATA":
// label DATA n,nn,'S' : the DATA pseudo-operation allows the programmer
// to enter fixed data into memory. Most assemblers allow more elaborate
// DATA instructions that handle a large amount of data at one time.
// => Not useful since we already have DEFB / DEFW / DEFM, and one type of value per line is better for readability
throw new Exception(String.Format("Line {0} : DATA directive is not supported", programLine.LineNumber));
case "END":
// END : indicates the end of the program. Any other statements following
// it will be ignored.
if (!String.IsNullOrEmpty(programLine.Label))
{
throw new Exception(String.Format("Line {0} : END directive does not allow a label", programLine.LineNumber));
}
else
{
return true;
}
// ==> Not supported yet, spectrum programs remain short by nature
case "MACRO":
// MACRO P0 P1 .. Pn : is used to define a label as a macro, and to define
// its formal parameter list.
throw new Exception(String.Format("Line {0} : MACRO directive is not supported", programLine.LineNumber));
case "ENDM":
// ENDM : is used to mark the end of macro definition.
throw new Exception(String.Format("Line {0} : ENDM directive is not supported", programLine.LineNumber));
}
return false;
}
public static Program GenerateProgram(string sourcePath, Stream machinecodeStream, int programStartAddress, CallTarget[] entryPoints, MemoryMap memoryMap)
{
// Load machine code in memory
int b = -1;
int currentAddress = programStartAddress;
while((b = machinecodeStream.ReadByte()) >= 0)
{
memoryMap.MemoryCells[currentAddress] = (byte)b;
memoryMap.MemoryCellDescriptions[currentAddress] = null; // Reset previous cell descriptions
currentAddress++;
}
int programEndAddress = currentAddress - 1;
// Check entry points
if (entryPoints == null || entryPoints.Length == 0)
{
throw new Exception("Entry point adresses are mandatory to try to decompile machine code");
}
foreach (CallTarget entryPoint in entryPoints)
{
if (entryPoint.Address < programStartAddress || entryPoint.Address > programEndAddress)
{
throw new Exception("Entry point adrress : " + entryPoint.Address + " is out of the range of the program");
}
}
// Initialize program
Program program = new Program(sourcePath, ProgramSource.ObjectCodeBinary);
program.BaseAddress = programStartAddress;
program.MaxAddress = programEndAddress;
memoryMap.Programs.Add(program);
program.Lines.Add( Assembler.ParseProgramLine("; **************************************************************************") );
program.Lines.Add( Assembler.ParseProgramLine("; * Decompiled assembly program for : " + sourcePath) );
program.Lines.Add( Assembler.ParseProgramLine("; **************************************************************************") );
program.Lines.Add( Assembler.ParseProgramLine("" ) );
program.Lines.Add( Assembler.ParseProgramLine("ORG " + FormatHexAddress(programStartAddress)) );
program.Lines.Add( Assembler.ParseProgramLine("") );
// Initialize code addresses to explore with entry points received as parameters
Queue<CallTarget> callTargetsToExplore = new Queue<CallTarget>();
foreach(CallTarget entryPoint in entryPoints)
{
callTargetsToExplore.Enqueue(entryPoint);
}
// The tracing decompiler will follow all the code paths
// and it will generate the program lines completely out of order.
// We can't add them to the program in the ascending
// order of the addresses during the first pass.
// So we store them in a temporary map for the second pass.
IDictionary<int, ProgramLine> generatedProgramLines = new SortedDictionary<int, ProgramLine>();
// Start from each call target and follow code path
while(callTargetsToExplore.Count > 0)
{
// Dequeue one code address to explore
CallTarget entryPoint = callTargetsToExplore.Dequeue();
currentAddress = entryPoint.Address;
// If this code address was already explored, do nothing
if (memoryMap.MemoryCellDescriptions[currentAddress] != null)
{
continue;
}
// Check if there is a limit in the number of opcodes to disassemble
bool stopDisassemblyAfterMaxNumberOfBytes = entryPoint.Source.CodeRelocationBytesCount > 0;
int maxNumberOfBytes = entryPoint.Source.CodeRelocationBytesCount;
InstructionFlowBehavior instructionFlowBehavior = 0;
do
{
// Check if instruction start address stays in the boundaries of the current program
if (currentAddress < programStartAddress || currentAddress > programEndAddress)
{
throw new Exception("Entry point address : " + currentAddress + " is out of the range of the program");
}
// Check if current address was already explored
if (memoryMap.MemoryCellDescriptions[currentAddress] != null)
{
break;
}
// Check if the maximum number of bytes to disassemble after the current entry point was reached
if (stopDisassemblyAfterMaxNumberOfBytes && (currentAddress - entryPoint.Address) >= maxNumberOfBytes)
{
break;
}
// Read one instruction code
int instructionStartAddress = currentAddress;
byte displacement;
InstructionCode instructionCode = ReadOneInstructionCode(memoryMap, ref currentAddress, out displacement);
// Check that instruction end address stays in the boundaries of the current program
int instructionEndAddress = instructionStartAddress + instructionCode.OpCodeByteCount + instructionCode.OperandsByteCount - 1;
if (instructionEndAddress > programEndAddress)
{
throw new Exception("End of instruction : " + instructionCode.InstructionType.OpCodeName + ", at address : " + instructionStartAddress + " is out of the range of the program");
}
// Read instruction code operands
byte operandByte1 = 0;
byte operandByte2 = 0;
if (instructionCode.OpCodeByteCount == 3)
{
operandByte1 = displacement;
}
else
{
if (instructionCode.OperandsByteCount >= 1)
{
operandByte1 = memoryMap.MemoryCells[currentAddress++];
}
if (instructionCode.OperandsByteCount == 2)
{
operandByte2 = memoryMap.MemoryCells[currentAddress++];
}
}
// Generate assembly text for the current instruction
string instructionLineText = GenerateInstructionLineText(instructionCode, operandByte1, operandByte2);
// Create a new program line from its textual representation
ProgramLine programLine = Assembler.ParseProgramLine(instructionLineText);
// Register the binary representation of the program line
programLine.LineAddress = instructionStartAddress;
programLine.InstructionCode = instructionCode;
programLine.InstructionType= instructionCode.InstructionType;
programLine.OperandByte1 = operandByte1;
programLine.OperandByte2 = operandByte2;
// Store the generated program line in the temporay map
generatedProgramLines.Add(instructionStartAddress, programLine);
// Register the signification of all the bytes of the instruction in the memory map
MemoryCellDescription instructionDescription = new MemoryCellDescription(MemoryDescriptionType.ProgramLine, programLine);
for (int instructionAddress = instructionStartAddress; instructionAddress <= instructionEndAddress; instructionAddress++)
{
memoryMap.MemoryCellDescriptions[instructionAddress] = instructionDescription;
}
// Analyse instruction effect on the program flow
// - check if the program flow continues to the next line
// - check if the current program line can jump elswhere (either always or depending on a condition)
// => register the outgoing call address in the program line
instructionFlowBehavior = ProgramFlowAnalyzer.GenerateOutgoingCall(programLine, null);
if(programLine.OutgoingCall != null)
{
// If target address was not explored before, add a new entry point to the list
if (memoryMap.MemoryCellDescriptions[programLine.OutgoingCall.Address] == null)
{
callTargetsToExplore.Enqueue(programLine.OutgoingCall);
}
}
}
// Continue to next instruction if the current instruction enables it
while ((instructionFlowBehavior & InstructionFlowBehavior.ContinueToNextInstruction) > 0);
}
// Find all the outgoing calls and register them as incoming calls on their target lines
ProgramFlowAnalyzer.GenerateIncomingCalls(generatedProgramLines.Values, memoryMap);
// To enhance the readability of the generated program
// Find all the incoming calls :
// - generate labels for the target lines
// Find all the outgoing calls
// - replace address references with labels in the source lines
Assembler.GenerateLabelsForIncomingAndOutgoingCalls(generatedProgramLines.Values, program.Variables);
// All the memory cells which were not hit during the exploration
// of all the code paths must represent data
MemoryCellDescription dataDescription = new MemoryCellDescription(MemoryDescriptionType.Data, null);
for (int programAddress = programStartAddress; programAddress <= programEndAddress; programAddress++)
{
if (memoryMap.MemoryCellDescriptions[programAddress] == null)
{
// Register in the memory map that this address contains data
memoryMap.MemoryCellDescriptions[programAddress] = dataDescription;
// Generate a program line to insert this byte of data
ProgramLine dataDirectiveLine = Assembler.ParseProgramLine("DEFB " + String.Format("{0:X2}H", memoryMap.MemoryCells[programAddress]));
// Register the binary representation of the program line
dataDirectiveLine.LineAddress = programAddress;
dataDirectiveLine.MemoryBytes = new byte[] { memoryMap.MemoryCells[programAddress] };
// Store the generated program line in the temporay map
generatedProgramLines.Add(programAddress, dataDirectiveLine);
}
}
// Add all generated program lines in the ascending order of their addresses
foreach (ProgramLine programLine in generatedProgramLines.Values)
{
programLine.LineNumber = program.Lines.Count + 1;
program.Lines.Add(programLine);
}
// Try to compile the generated program and check that it produces the right machine code output
// NB : !! remove this step when the decompiler is well tested and mature !!
MemoryMap generatedProgramMachineCode = new MemoryMap(memoryMap.MemoryCells.Length);
Assembler.CompileProgram(program, programStartAddress, generatedProgramMachineCode);
for (int programAddress = programStartAddress; programAddress <= programEndAddress; programAddress++)
{
if (generatedProgramMachineCode.MemoryCells[programAddress] != memoryMap.MemoryCells[programAddress])
{
throw new Exception("Error in decompiled program at address " + programAddress + " : source byte = " + memoryMap.MemoryCells[programAddress] + ", decompiled program line + " + ((ProgramLine)memoryMap.MemoryCellDescriptions[programAddress].Description).Text + " produced byte = " + generatedProgramMachineCode.MemoryCells[programAddress]);
}
}
return program;
}
public static Program GenerateProgram(string sourcePath, Stream machinecodeStream, int programStartAddress, CallTarget[] entryPoints, MemoryMap memoryMap)
{
// Load machine code in memory
int b = -1;
int currentAddress = programStartAddress;
while ((b = machinecodeStream.ReadByte()) >= 0)
{
memoryMap.MemoryCells[currentAddress] = (byte)b;
memoryMap.MemoryCellDescriptions[currentAddress] = null; // Reset previous cell descriptions
currentAddress++;
}
int programEndAddress = currentAddress - 1;
// Check entry points
if (entryPoints == null || entryPoints.Length == 0)
{
throw new Exception("Entry point adresses are mandatory to try to decompile machine code");
}
foreach (CallTarget entryPoint in entryPoints)
{
if (entryPoint.Address < programStartAddress || entryPoint.Address > programEndAddress)
{
throw new Exception("Entry point adrress : " + entryPoint.Address + " is out of the range of the program");
}
}
// Initialize program
Program program = new Program(sourcePath, ProgramSource.ObjectCodeBinary);
program.BaseAddress = programStartAddress;
program.MaxAddress = programEndAddress;
memoryMap.Programs.Add(program);
program.Lines.Add(Assembler.ParseProgramLine("; **************************************************************************"));
program.Lines.Add(Assembler.ParseProgramLine("; * Decompiled assembly program for : " + sourcePath));
program.Lines.Add(Assembler.ParseProgramLine("; **************************************************************************"));
program.Lines.Add(Assembler.ParseProgramLine(""));
program.Lines.Add(Assembler.ParseProgramLine("ORG " + FormatHexAddress(programStartAddress)));
program.Lines.Add(Assembler.ParseProgramLine(""));
// Initialize code addresses to explore with entry points received as parameters
Queue <CallTarget> callTargetsToExplore = new Queue <CallTarget>();
foreach (CallTarget entryPoint in entryPoints)
{
callTargetsToExplore.Enqueue(entryPoint);
}
// The tracing decompiler will follow all the code paths
// and it will generate the program lines completely out of order.
// We can't add them to the program in the ascending
// order of the addresses during the first pass.
// So we store them in a temporary map for the second pass.
IDictionary <int, ProgramLine> generatedProgramLines = new SortedDictionary <int, ProgramLine>();
// Start from each call target and follow code path
while (callTargetsToExplore.Count > 0)
{
// Dequeue one code address to explore
CallTarget entryPoint = callTargetsToExplore.Dequeue();
currentAddress = entryPoint.Address;
// If this code address was already explored, do nothing
if (memoryMap.MemoryCellDescriptions[currentAddress] != null)
{
continue;
}
// Check if there is a limit in the number of opcodes to disassemble
bool stopDisassemblyAfterMaxNumberOfBytes = entryPoint.Source.CodeRelocationBytesCount > 0;
int maxNumberOfBytes = entryPoint.Source.CodeRelocationBytesCount;
InstructionFlowBehavior instructionFlowBehavior = 0;
do
{
// Check if instruction start address stays in the boundaries of the current program
if (currentAddress < programStartAddress || currentAddress > programEndAddress)
{
throw new Exception("Entry point address : " + currentAddress + " is out of the range of the program");
}
// Check if current address was already explored
if (memoryMap.MemoryCellDescriptions[currentAddress] != null)
{
break;
}
// Check if the maximum number of bytes to disassemble after the current entry point was reached
if (stopDisassemblyAfterMaxNumberOfBytes && (currentAddress - entryPoint.Address) >= maxNumberOfBytes)
{
break;
}
// Read one instruction code
int instructionStartAddress = currentAddress;
byte displacement;
InstructionCode instructionCode = ReadOneInstructionCode(memoryMap, ref currentAddress, out displacement);
// Check that instruction end address stays in the boundaries of the current program
int instructionEndAddress = instructionStartAddress + instructionCode.OpCodeByteCount + instructionCode.OperandsByteCount - 1;
if (instructionEndAddress > programEndAddress)
{
throw new Exception("End of instruction : " + instructionCode.InstructionType.OpCodeName + ", at address : " + instructionStartAddress + " is out of the range of the program");
}
// Read instruction code operands
byte operandByte1 = 0;
byte operandByte2 = 0;
if (instructionCode.OpCodeByteCount == 3)
{
operandByte1 = displacement;
}
else
{
if (instructionCode.OperandsByteCount >= 1)
{
operandByte1 = memoryMap.MemoryCells[currentAddress++];
}
if (instructionCode.OperandsByteCount == 2)
{
operandByte2 = memoryMap.MemoryCells[currentAddress++];
}
}
// Generate assembly text for the current instruction
string instructionLineText = GenerateInstructionLineText(instructionCode, operandByte1, operandByte2);
// Create a new program line from its textual representation
ProgramLine programLine = Assembler.ParseProgramLine(instructionLineText);
// Register the binary representation of the program line
programLine.LineAddress = instructionStartAddress;
programLine.InstructionCode = instructionCode;
programLine.InstructionType = instructionCode.InstructionType;
programLine.OperandByte1 = operandByte1;
programLine.OperandByte2 = operandByte2;
// Store the generated program line in the temporay map
generatedProgramLines.Add(instructionStartAddress, programLine);
// Register the signification of all the bytes of the instruction in the memory map
MemoryCellDescription instructionDescription = new MemoryCellDescription(MemoryDescriptionType.ProgramLine, programLine);
for (int instructionAddress = instructionStartAddress; instructionAddress <= instructionEndAddress; instructionAddress++)
{
memoryMap.MemoryCellDescriptions[instructionAddress] = instructionDescription;
}
// Analyse instruction effect on the program flow
// - check if the program flow continues to the next line
// - check if the current program line can jump elswhere (either always or depending on a condition)
// => register the outgoing call address in the program line
instructionFlowBehavior = ProgramFlowAnalyzer.GenerateOutgoingCall(programLine, null);
if (programLine.OutgoingCall != null)
{
// If target address was not explored before, add a new entry point to the list
if (memoryMap.MemoryCellDescriptions[programLine.OutgoingCall.Address] == null)
{
callTargetsToExplore.Enqueue(programLine.OutgoingCall);
}
}
}
// Continue to next instruction if the current instruction enables it
while ((instructionFlowBehavior & InstructionFlowBehavior.ContinueToNextInstruction) > 0);
}
// Find all the outgoing calls and register them as incoming calls on their target lines
ProgramFlowAnalyzer.GenerateIncomingCalls(generatedProgramLines.Values, memoryMap);
// To enhance the readability of the generated program
// Find all the incoming calls :
// - generate labels for the target lines
// Find all the outgoing calls
// - replace address references with labels in the source lines
Assembler.GenerateLabelsForIncomingAndOutgoingCalls(generatedProgramLines.Values, program.Variables);
// All the memory cells which were not hit during the exploration
// of all the code paths must represent data
MemoryCellDescription dataDescription = new MemoryCellDescription(MemoryDescriptionType.Data, null);
for (int programAddress = programStartAddress; programAddress <= programEndAddress; programAddress++)
{
if (memoryMap.MemoryCellDescriptions[programAddress] == null)
{
// Register in the memory map that this address contains data
memoryMap.MemoryCellDescriptions[programAddress] = dataDescription;
// Generate a program line to insert this byte of data
ProgramLine dataDirectiveLine = Assembler.ParseProgramLine("DEFB " + String.Format("{0:X2}H", memoryMap.MemoryCells[programAddress]));
// Register the binary representation of the program line
dataDirectiveLine.LineAddress = programAddress;
dataDirectiveLine.MemoryBytes = new byte[] { memoryMap.MemoryCells[programAddress] };
// Store the generated program line in the temporay map
generatedProgramLines.Add(programAddress, dataDirectiveLine);
}
}
// Add all generated program lines in the ascending order of their addresses
foreach (ProgramLine programLine in generatedProgramLines.Values)
{
programLine.LineNumber = program.Lines.Count + 1;
program.Lines.Add(programLine);
}
// Try to compile the generated program and check that it produces the right machine code output
// NB : !! remove this step when the decompiler is well tested and mature !!
MemoryMap generatedProgramMachineCode = new MemoryMap(memoryMap.MemoryCells.Length);
Assembler.CompileProgram(program, programStartAddress, generatedProgramMachineCode);
for (int programAddress = programStartAddress; programAddress <= programEndAddress; programAddress++)
{
if (generatedProgramMachineCode.MemoryCells[programAddress] != memoryMap.MemoryCells[programAddress])
{
throw new Exception("Error in decompiled program at address " + programAddress + " : source byte = " + memoryMap.MemoryCells[programAddress] + ", decompiled program line + " + ((ProgramLine)memoryMap.MemoryCellDescriptions[programAddress].Description).Text + " produced byte = " + generatedProgramMachineCode.MemoryCells[programAddress]);
}
}
return(program);
}
public MemoryMap(int size)
{
MemoryCells = new byte[size];
MemoryCellDescriptions = new MemoryCellDescription[size];
Programs = new List<Program>();
}
public SpectrumMemoryMap()
: base(65536)
{
// Load ROM assembly source code
string sourcePath = "zxspectrum.asm";
string romProgramText = LoadROMAssemblySource(sourcePath);
// Parse ROM program
using (Stream romProgramStream = new MemoryStream(Encoding.UTF8.GetBytes(romProgramText)))
{
ROM = Assembler.ParseProgram(sourcePath, romProgramStream, Encoding.UTF8, false);
}
// Compile ROM program and store it in memeory
Assembler.CompileProgram(ROM, 0, this);
// Analyze ROM ProgramFlow
Assembler.AnalyzeProgramFlow(ROM, this);
// Register system variables descriptions
foreach (SpectrumSystemVariable variable in SystemVariables.Values)
{
for (int i = variable.Address; i < (variable.Address + variable.Length); i++)
{
MemoryCellDescriptions[i] = new MemoryCellDescription(MemoryDescriptionType.SystemVariable, variable);
}
}
}
