public byte[] Assemble()
{
ICollection <AddressableInstruction> sourceTree = ParseSource();
AddressableInstruction lastInstruction = sourceTree.Last();
long binarySize = lastInstruction.Address.BinaryAddress + lastInstruction.BinaryLength;
// Create an array of the required size to hold the binary data.
// Size is taken from the final binary address used.
byte[] binary = new byte[binarySize];
// Assemble the binary for each instruction and store it in the array.
foreach (AddressableInstruction instruction in sourceTree)
{
byte[] instructionBinary = instruction.AssembleBinary();
Array.Copy(instructionBinary, 0, binary, instruction.Address.BinaryAddress, instruction.BinaryLength);
}
return(binary);
}
private ICollection <AddressableInstruction> ParseSource()
{
InstructionFactory instructionParser = new InstructionFactory();
// We parse the source and build a list of all source
// instructions (including comments), and a dictionary
// of executable instructions, indexed by their source
// starting address.
List <Instruction> sourceList = new List <Instruction>();
Dictionary <int, AddressableInstruction> instructionDictionary = new Dictionary <int, AddressableInstruction>();
Dictionary <String, AddressableInstruction> labeledInstructionDictionary = new Dictionary <string, AddressableInstruction>();
int instructionSourceAddress = 0;
int instructionSourceLineNumber = 0;
// Loop through each line of source code and create an instruction for it.
foreach (String sourceLine in _sourceCodeLines)
{
Instruction sourceInstruction = instructionParser.GenerateInstruction(sourceLine, instructionSourceLineNumber, instructionSourceAddress);
if (sourceInstruction != null)
{
AddressableInstruction addressableInstruction = sourceInstruction as AddressableInstruction;
if (addressableInstruction != null)
{
instructionDictionary.Add(instructionSourceAddress, addressableInstruction);
// If the instruction has a label, store a mapping so we can resolve labeled branches later.
if (!String.IsNullOrEmpty(addressableInstruction.Address.AddressLabel))
{
labeledInstructionDictionary.Add(addressableInstruction.Address.AddressLabel, addressableInstruction);
}
instructionSourceAddress += addressableInstruction.SourceLength;
}
sourceList.Add(sourceInstruction);
instructionSourceLineNumber++;
}
}
// Loop through each instruction and map each branch address to the destination instruction.
// This is done at the source level at this stage so we have a correctly mapped instruction
// tree before we start generating binary and create the actual addresses.
foreach (var instruction in instructionDictionary)
{
IBranchingInstruction branchingInstruction = instruction.Value as IBranchingInstruction;
if (branchingInstruction != null)
{
branchingInstruction.MapBranchAddress(instructionDictionary, labeledInstructionDictionary);
}
IAddressedOperands addressedOperandsInstruction = instruction.Value as IAddressedOperands;
if (addressedOperandsInstruction != null)
{
addressedOperandsInstruction.MapAddressedOperands(instructionDictionary, labeledInstructionDictionary);
}
AddressableMemoryInstruction memoryValue = instruction.Value as AddressableMemoryInstruction;
if (memoryValue != null)
{
memoryValue.MapMemoryValue(instructionDictionary, labeledInstructionDictionary);
}
}
return(instructionDictionary.Values);
}