private void WriteElfFileToMemory(FileStream strm, ELF elfHeader, byte[] data)
{
Trace.WriteLine("Loader: Reading ELF File...");
strm.Seek(elfHeader.e_phoff, SeekOrigin.Begin); // seek to the program header offset
data = new byte[elfHeader.e_phentsize]; // allocate byte array the size of the program header
strm.Read(data, 0, (int)elfHeader.e_phentsize); // <data> contains program header
int p_offset = (int)BitConverter.ToUInt16(data, 4); // read start of segment
int p_filesz = (int)BitConverter.ToUInt16(data, 16); // read file size
uint p_vaddr = BitConverter.ToUInt16(data, 8); // read storage address
Trace.WriteLine("Loader: Reading program header...");
strm.Seek(p_offset, SeekOrigin.Begin); // seek to beginning of program segment
byte[] programData = new byte[p_filesz]; // create holder for program data
Trace.WriteLine("Loader: Program header offset: " + p_offset);
Trace.WriteLine("Loader: Program file size: " + p_filesz);
Trace.WriteLine("Loader: Writing program to RAM...");
strm.Read(programData, 0, p_filesz); // read program into <programData>
for (uint j = 0; j < programData.Length; j++)
{
Computer.GetCPU().progRAM.WriteByte(p_vaddr + j, programData[j]);
}
elfHeader.e_phoff += elfHeader.e_phentsize; // move to next program header
Trace.WriteLine("Loader: Program written to RAM successfully!");
Trace.WriteLine(""); // blank line for file readability
}
//--------------------------------------------------------------
// Purpose: Reads ELF files into simulated ram after validating their ELFness
// Returns: bool value true if loading completed successfully
//--------------------------------------------------------------
public bool ReadELF(string ELFpath)
{
bool success = false;
try
{
Trace.WriteLine("Loader: Opening file " + ELFpath + "...");
using (FileStream strm = new FileStream(ELFpath, FileMode.Open))
{
ELF elfHeader = new ELF();
byte[] data = new byte[Marshal.SizeOf(elfHeader)];
// read ELF header data
strm.Read(data, 0, data.Length);
// convert to struct
elfHeader = ByteArrayToStructure <ELF>(data);
Trace.WriteLine("Loader: Checking if valid ELF file...");
// check to ensure file is an ELF file
if (!(data[0] == '\x7f' &&
data[1] == 'E' &&
data[2] == 'L' &&
data[3] == 'F'))
{
throw new InvalidDataException();
}
Trace.WriteLine("Loader: File check complete!");
Trace.WriteLine("Loader: Number of segments: " + elfHeader.e_phnum);
Trace.WriteLine(""); // blank line for file readability
registers.WriteWord((uint)regs.PC, elfHeader.e_entry);
registers.WriteWord((uint)regs.SP, 0x00007000);
// Read first program header entry
for (int i = 0; i < elfHeader.e_phnum; i++)
{
WriteElfFileToMemory(strm, elfHeader, data);
}
success = true;
}
}
catch (InvalidDataException)
{
Console.WriteLine("Loader: The file provided is not an ELF file. Please try again.");
Trace.WriteLine("Loader: The file provided is not an ELF file. Please try again.");
}
catch (FileNotFoundException)
{
Console.WriteLine("Loader: Could not locate file " + ELFpath + ". Please try again.");
Trace.WriteLine("Loader: Could not locate file " + ELFpath + ". Please try again.");
}
catch (Exception ex)
{
Console.WriteLine("Loader: Unknown error. " + ex.ToString());
Trace.WriteLine("Loader: Unknown error. " + ex.ToString());
}
return(success);
}
