/// <summary>
/// Reads LDA data blocks
/// </summary>
/// <remarks>
/// The format of LDA blocks is:
/// +------+
/// | 0001 | - word16 - Magic
/// |------|
/// | BC | - word16 - Count
/// |------|
/// | ADDR | - word16 - Absolute load address
/// |------|
/// | Data | - byte[] - Data (`Count` bytes, including the first 6 bytes)
/// ...
/// |------|
/// | Chk | - byte - Checksum
/// +------+
/// </remarks>
/// <param name="rdr"></param>
/// <returns></returns>
public Tuple<ushort, byte[]> ReadDataBlock(LeImageReader rdr)
{
ushort count;
ushort uAddr;
byte b;
// Eat bytes until 1 followed by 0.
do
{
while (rdr.TryReadByte(out b) && b != 1)
;
if (b != 1)
return null; // invalid file
if (!rdr.TryReadByte(out b))
return null;
} while (b != 0);
if (!rdr.TryReadLeUInt16(out count))
return null;
if (!rdr.TryReadLeUInt16(out uAddr))
return null;
if (count == 6)
return new Tuple<ushort, byte[]>(uAddr, null);
var data = rdr.ReadBytes(count - 6);
if (data == null || data.Length < count - 6)
return null;
if (!rdr.TryReadByte(out b)) // read (and ignore) checksum
return null;
Debug.Print("Data block: {0:X4} {1:X4}", uAddr, count);
return Tuple.Create(uAddr, data);
}
/// <summary>
/// Reads LDA data blocks
/// </summary>
/// <remarks>
/// The format of LDA blocks is:
/// +------+
/// | 0001 | - word16 - Magic
/// |------|
/// | BC | - word16 - Count
/// |------|
/// | ADDR | - word16 - Absolute load address
/// |------|
/// | Data | - byte[] - Data (`Count` bytes, including the first 6 bytes)
/// ...
/// |------|
/// | Chk | - byte - Checksum
/// +------+
/// </remarks>
/// <param name="rdr"></param>
/// <returns></returns>
public (ushort, byte[]?) ReadDataBlock(LeImageReader rdr)
{
ushort count;
ushort uAddr;
byte b;
// Eat bytes until 1 followed by 0.
do
{
while (rdr.TryReadByte(out b) && b != 1)
{
;
}
if (b != 1)
{
return(0, null); // invalid file
}
if (!rdr.TryReadByte(out b))
{
return(0, null);
}
} while (b != 0);
if (!rdr.TryReadLeUInt16(out count))
{
return(0, null);
}
if (!rdr.TryReadLeUInt16(out uAddr))
{
return(0, null);
}
if (count == 6)
{
return(uAddr, null);
}
var data = rdr.ReadBytes(count - 6);
if (data == null || data.Length < count - 6)
{
return(0, null);
}
if (!rdr.TryReadByte(out b)) // read (and ignore) checksum
{
return(0, null);
}
Debug.Print("Data block: {0:X4} {1:X4}", uAddr, count);
return(uAddr, data);
}
/// <summary>
/// Reads LDA data blocks
/// </summary>
/// <remarks>
/// The format of LDA blocks is:
/// +------+
/// | 0001 | - word16 - Magic
/// |------|
/// | BC | - word16 - Count
/// |------|
/// | ADDR | - word16 - Absolute load address
/// |------|
/// | Data | - byte[] - Data (`Count` bytes)
/// ...
/// |------|
/// | Chk | - byte - Checksum
/// +------+
/// </remarks>
/// <param name="rdr"></param>
/// <returns></returns>
public ImageSegment ReadDataBlock(LeImageReader rdr)
{
ushort w;
ushort count;
ushort uAddr;
byte b;
if (!rdr.TryReadLeUInt16(out w) || w != 0x0001)
{
return(null);
}
if (!rdr.TryReadLeUInt16(out count))
{
return(null);
}
if (!rdr.TryReadLeUInt16(out uAddr))
{
return(null);
}
var data = rdr.ReadBytes(count);
if (data == null || data.Length < count)
{
return(null);
}
if (!rdr.TryReadByte(out b))
{
return(null);
}
Debug.Print("Data block: {0:X4} {1:X4}", uAddr, count);
return(new ImageSegment(
string.Format("seg{0:X4}", uAddr),
new MemoryArea(Address.Ptr16(uAddr), data),
AccessMode.ReadWriteExecute));
}
public override TypeLibrary Load(IPlatform platform, TypeLibrary dstLib)
{
var loader = new TypeLibraryDeserializer(platform, true, dstLib);
var rdr = new LeImageReader(rawImage);
var(type, _) = ReadRecord(rdr);
if (type != RecordType.LibraryHeader)
{
return(dstLib);
}
(type, _) = ReadRecord(rdr);
if (type != RecordType.THEADR)
{
return(dstLib);
}
for (; ;)
{
byte[] data;
(type, data) = ReadRecord(rdr);
if (data == null)
{
break;
}
switch (type)
{
default: throw new NotImplementedException($"OMF record type {type} ({(int) type:X} has not been implemented yet.");
case RecordType.THEADR:
// Can't seem to do anything useful with THEADRs
break;
case RecordType.COMENT:
var rdrComent = new LeImageReader(data);
if (!rdrComent.TryReadByte(out byte _)) // Ignore the comment type
{
break;
}
if (!rdrComent.TryReadByte(out byte cmtClass))
{
break;
}
if ((CommentClass)cmtClass != CommentClass.Extensions)
{
break;
}
if (!rdrComent.TryReadByte(out byte cmtExt))
{
break;
}
if ((CommentExtension)cmtExt == CommentExtension.IMPDEF)
{
ReadImpdef(rdrComent, loader);
}
else
{
throw new NotImplementedException($"OMF COMENT extension {(CommentExtension) cmtExt} (0x{cmtExt:X}) is not implemented yet.");
}
break;
case RecordType.MODEND:
// Modend's seem to be followed by padding to a 16-byte boundary.
while ((rdr.Offset & 0xF) != 0 && rdr.TryReadByte(out _))
{
;
}
break;
case RecordType.LibraryEnd:
return(dstLib);
}
}
return(dstLib);
}
