private void Given_Omf(RecordType rt, ushort length, params Action [] mutators)
{
writer.WriteByte((byte)rt);
writer.WriteLeUInt16(length);
foreach (var mutator in mutators)
{
mutator();
}
}
/// <summary>
/// Create a segment for the MS-DOS program segment prefix (PSP).
/// </summary>
/// <param name="addrPsp">The address of the PSP</param>
/// <param name="segMemTop">The segment address (paragraph) of the first byte
/// beyond the image.</param>
/// <returns>
/// An <see cref="ImageSegment"/> that can be added to a <see cref="SegmentMap"/>.
/// </returns>
private ImageSegment MakeProgramSegmentPrefix(Address addrPsp, ushort segMemTop)
{
var mem = new ByteMemoryArea(addrPsp, new byte[0x100]);
var w = new LeImageWriter(mem, 0);
w.WriteByte(0xCD);
w.WriteByte(0x20);
w.WriteLeUInt16(segMemTop); // Some unpackers rely on this value.
return(new ImageSegment("PSP", mem, AccessMode.ReadWriteExecute));
}
public void Given_DebugHeader(short nSymbols, short nTypes)
{
writer.WriteLeUInt16(SymbolLoader.MagicNumber); // magic_number
writer.WriteLeUInt16(0); // version_id
// Remember this position so we can backpatch later.
this.offNames = writer.Position;
writer.WriteLeUInt32(0); // names
writer.WriteLeUInt16(0); // names_count
writer.WriteLeInt16(nTypes); // types_count
writer.WriteLeUInt16(0); // members_count
writer.WriteLeInt16(nSymbols); // symbols_count
writer.WriteLeUInt16(0); // globals_count
writer.WriteLeUInt16(0); // modules_count
writer.WriteLeUInt16(0); // locals_count
writer.WriteLeUInt16(0); // scopes_count
writer.WriteLeUInt16(0); // lines_count
writer.WriteLeUInt16(0); // source_count
writer.WriteLeUInt16(0); // segment_count
writer.WriteLeUInt16(0); // correlation_count
writer.WriteUInt32(0); // image_size
writer.WriteUInt32(0); // /*void far * */debugger_hook
writer.WriteByte(0); // program_flags
writer.WriteLeUInt16(0); // stringsegoffset
writer.WriteLeUInt16(0); // data_count
writer.WriteByte(0); // filler
writer.WriteLeUInt16(0x00); // extension_size
}
private void Given_Bundle(byte nEntries, byte iSeg, params BundleEntry[] entries)
{
writer.WriteByte(nEntries);
writer.WriteByte(iSeg);
foreach (var entry in entries)
{
writer.WriteByte(entry.flags);
if (entry.flags == 0)
{
break;
}
if (entry.iSeg != 0)
{
writer.WriteBeUInt16(0xCD3F); // INT 3F [sic]
writer.WriteByte(entry.iSeg);
}
writer.WriteLeUInt16(entry.offset);
}
}
private void Given_IndirectTable_UInt32(Address address, Address addrIndirect, params uint[] entries)
{
ImageSegment seg;
program.SegmentMap.Segments.TryGetValue(address, out seg);
var writer = new LeImageWriter(seg.MemoryArea, address);
foreach (uint entry in entries)
{
writer.WriteLeUInt32(entry);
}
writer = new LeImageWriter(seg.MemoryArea, addrIndirect);
for (int i = 0; i < entries.Length; ++i)
{
writer.WriteByte((byte)i);
}
}
private int Given_ImportDescriptor32(
int rvaIlt,
string dllName,
int rvaIat)
{
var rvaDllName = writer.Position;
writer.WriteString(dllName, Encoding.UTF8);
writer.WriteByte(0);
var rvaId = writer.Position;
writer.WriteLeInt32(rvaIlt);
writer.WriteLeInt32(0); // (ignored) datestamp
writer.WriteLeInt32(0); // forwarder chain
writer.WriteLeInt32((int)rvaDllName);
writer.WriteLeInt32(rvaIat);
return((int)rvaId);
}
private byte[] CreateMsdosHeader()
{
ImageWriter stm = new LeImageWriter(new byte[16]);
stm.WriteByte(0x4D); // MZ
stm.WriteByte(0x5A);
stm.WriteBytes(0xCC, 4);
stm.WriteLeUInt16(0x0090);
stm.WriteBytes(0xCC, 0x12);
stm.WriteByte(0x00);
stm.WriteByte(0x00);
stm.WriteByte(0x05);
stm.WriteByte(0x21);
stm.WriteString("PKLITE", Encoding.ASCII);
stm.WriteBytes(0xCC, 0x0C);
return(stm.Bytes);
}
/// <summary>
/// Unpacks the packed raw image into <paramref name="image" />.
/// </summary>
private void UnpackImage(FileHeader fileHeader, ByteMemoryArea image)
{
var w = new LeImageWriter(image.Bytes);
//
// Still looking for additional information on Pharlap file packing
//
// Packing implemented is currently based on reviewing code and interpretation of data against loading program in debugger.
// Record is 16 bit word.
// If bit 15 is clear ie 0-7FFF, load the next record number of bytes into memory
//
// If bit 15 is set, ie 8000-FFFF use value lower 15 bits for size of repeat area
// Next byte (dataSize) defines size of item to be repeated
// If dataSize size is larger than size of repeat area, corrupt file
// if dataSize is 0, then is either fill with zero or skip, size of repeat area
// Read itemSize number of bytes for the repeatData
// copying repeatData until filled size of repeat area
//
var rdr = new LeImageReader(RawImage, FileHeaderOffset + fileHeader.offset_load_image);
while (w.Position < fileHeader.memory_requirements)
{
if (!rdr.TryReadUInt16(out ushort us))
{
throw new BadImageFormatException("Unexpected EOF while loading program.");
}
if ((us & 0x8000) == 0)
{
rdr.ReadBytes(w.Bytes, w.Position, us);
w.Position += us;
}
else
{
us &= 0x7FFF;
if (!rdr.TryReadByte(out var dataSize))
{
throw new BadImageFormatException("Unexpected EOF while loading program.");
}
if (dataSize > us)
{
throw new BadImageFormatException("Corrupt file"); // Corrupt file, Repeated data shouldn't be bigger than size of repeat block
}
if (dataSize == 0)
{
for (int i = 0; i < us; ++i)
{
w.WriteByte(dataSize);
}
}
else
{
var repeatData = new byte[dataSize];
for (int i = 0; i < dataSize; ++i)
{
if (!rdr.TryReadByte(out var b))
{
throw new BadImageFormatException("Unexpected EOF while loading program.");
}
repeatData[i] = b;
}
for (int i = 0; i < us; i += dataSize)
{
w.WriteBytes(repeatData);
}
}
}
}
}
