private bool ReadMasterBootBlock()
{
valid = false;
if (diskDevice.BlockSize != 512) // only going to work with 512 sector sizes
{
return(false);
}
BinaryFormat masterboot = new BinaryFormat(diskDevice.ReadBlock(0, 1));
ushort mbrsignature = masterboot.GetUShort(MasterBootRecord.MBRSignature);
diskSignature = masterboot.GetUInt(MasterBootRecord.DiskSignature);
valid = (mbrsignature == MasterBootConstants.MBRSignature);
if (valid)
{
for (uint index = 0; index < MaxMBRPartitions; index++)
{
uint offset = MasterBootRecord.PrimaryPartitions + (index * 16);
GenericPartition partition = new GenericPartition(index);
partition.Bootable = masterboot.GetByte(offset + PartitionRecord.Status) == 0x80;
partition.PartitionType = masterboot.GetByte(offset + PartitionRecord.PartitionType);
partition.StartLBA = masterboot.GetUInt(offset + PartitionRecord.LBA);
partition.TotalBlocks = masterboot.GetUInt(offset + PartitionRecord.Sectors);
partitions[index] = partition;
}
//TODO: Extended Partitions
}
code = new byte[MasterBootConstants.CodeAreaSize];
for (uint index = 0; index < MasterBootConstants.CodeAreaSize; index++)
{
code[index] = masterboot.GetByte(index);
}
return(valid);
}
private bool ReadMasterBootBlock ()
{
valid = false;
if (diskDevice.BlockSize != 512) // only going to work with 512 sector sizes
return false;
BinaryFormat masterboot = new BinaryFormat (diskDevice.ReadBlock (0, 1));
ushort mbrsignature = masterboot.GetUShort (MasterBootRecord.MBRSignature);
diskSignature = masterboot.GetUInt (MasterBootRecord.DiskSignature);
valid = (mbrsignature == MasterBootConstants.MBRSignature);
if (valid) {
for (uint index = 0; index < MaxMBRPartitions; index++) {
uint offset = MasterBootRecord.PrimaryPartitions + (index * 16);
GenericPartition partition = new GenericPartition (index);
partition.Bootable = masterboot.GetByte (offset + PartitionRecord.Status) == 0x80;
partition.PartitionType = masterboot.GetByte (offset + PartitionRecord.PartitionType);
partition.StartLBA = masterboot.GetUInt (offset + PartitionRecord.LBA);
partition.TotalBlocks = masterboot.GetUInt (offset + PartitionRecord.Sectors);
partitions[index] = partition;
}
//TODO: Extended Partitions
}
code = new byte[MasterBootConstants.CodeAreaSize];
for (uint index = 0; index < MasterBootConstants.CodeAreaSize; index++)
code[index] = masterboot.GetByte (index);
return valid;
}
// doesn't work since uint should be uint64
//protected bool ReadLBA48 (SectorOperation operation, uint drive, uint lba, MemoryBlock memory)
//{
// FeaturePort.Write8 (0);
// FeaturePort.Write8 (0);
// SectorCountPort.Write8 (0);
// SectorCountPort.Write8 (1);
// LBALowPort.Write8 ((byte)((lba >> 24) & 0xFF));
// LBALowPort.Write8 ((byte)(lba & 0xFF));
// LBAMidPort.Write8 ((byte)((lba >> 32) & 0xFF));
// LBAMidPort.Write8 ((byte)((lba >> 8) & 0xFF));
// LBAHighPort.Write8 ((byte)((lba >> 40) & 0xFF));
// LBAHighPort.Write8 ((byte)((lba >> 16) & 0xFF));
// DeviceHeadPort.Write8 ((byte)(0x40 | (drive << 4)));
// if (operation == SectorOperation.Write)
// CommandPort.Write8 (0x34);
// else
// CommandPort.Write8 (0x24);
// if (!WaitForReqisterReady ())
// return false;
// //TODO: Don't use PIO
// if (operation == SectorOperation.Read) {
// for (uint index = 0; index < 256; index++)
// memory.SetUShort (index * 2, DataPort.Read16 ());
// }
// else {
// for (uint index = 0; index < 256; index++)
// DataPort.WriteUShort (memory.GetUShort (index * 2));
// }
// return true;
//}
public bool Open (uint driveNbr)
{
if (driveNbr == 0)
DeviceHeadPort.Write8 (0xA0);
else
if (driveNbr == 1)
DeviceHeadPort.Write8 (0xB0);
else
return false;
CommandPort.Write8 (IDECommand.IdentifyDrive);
if (!WaitForReqisterReady ())
return false;
BinaryFormat info = new BinaryFormat (new byte[512]);
for (uint index = 0; index < 256; index++)
info.SetUShort (index * 2, DataPort.Read16 ());
driveInfo[driveNbr].MaxLBA = info.GetUInt (IdentifyDrive.MaxLBA28);
// legacy info
driveInfo[driveNbr].Heads = info.GetUShort (IdentifyDrive.LogicalHeads);
driveInfo[driveNbr].Cylinders = info.GetUShort (IdentifyDrive.LogicalCylinders);
driveInfo[driveNbr].SectorsPerTrack = info.GetUShort (IdentifyDrive.LogicalSectors);
return true;
}
public uint GetFileSize (uint directoryBlock, uint index)
{
BinaryFormat directory = new BinaryFormat (partition.ReadBlock (directoryBlock, 1));
return directory.GetUInt ((index * Entry.EntrySize) + Entry.FileSize);
}
//protected uint ClusterToFirstSector (uint cluster)
//{
// return ((cluster - 2) * sectorspercluster) + firstdatasector;
//}
protected uint GetClusterEntryValue (uint cluster)
{
uint fatoffset = 0;
if (fatType == FATType.FAT12)
fatoffset = (cluster + (cluster / 2));
else if (fatType == FATType.FAT16)
fatoffset = cluster * 2;
else //if (type == FatType.FAT32)
fatoffset = cluster * 4;
uint sector = fatStart + (fatoffset / bytesPerSector);
uint sectorOffset = fatoffset % bytesPerSector;
uint nbrSectors = 1;
if ((fatType == FATType.FAT12) && (sectorOffset == bytesPerSector - 1))
nbrSectors = 2;
BinaryFormat fat = new BinaryFormat (partition.ReadBlock (sector, nbrSectors));
uint clusterValue;
if (fatType == FATType.FAT12) {
clusterValue = fat.GetUShort (sectorOffset);
if (cluster % 2 == 1)
clusterValue = clusterValue >> 4;
else
clusterValue = clusterValue & 0x0fff;
}
else if (fatType == FATType.FAT16)
clusterValue = fat.GetUShort (sectorOffset);
else //if (type == FatType.FAT32)
clusterValue = fat.GetUInt (sectorOffset) & 0x0fffffff;
return clusterValue;
}
protected bool ReadBootSector ()
{
valid = false;
if (blockSize != 512) // only going to work with 512 sector sizes (for now)
return false;
BinaryFormat bootSector = new BinaryFormat (partition.ReadBlock (0, 1));
byte bootSignature = bootSector.GetByte (BootSector.ExtendedBootSignature);
if ((bootSignature != 0x29) && (bootSignature != 0x28))
return false;
//TextMode.Write ("EOM NAME: ");
//for (uint i = 0; i < 8; i++)
// TextMode.WriteChar (bootsector.GetByte (BootSector.EOMName + i));
//TextMode.WriteLine ();
bytesPerSector = bootSector.GetUShort (BootSector.BytesPerSector);
sectorsPerCluster = bootSector.GetByte (BootSector.SectorsPerCluster);
reservedSectors = bootSector.GetByte (BootSector.ReservedSectors);
nbrFats = bootSector.GetByte (BootSector.FatAllocationTables);
rootEntries = bootSector.GetUShort (BootSector.MaxRootDirEntries);
uint sectorsPerFat16 = bootSector.GetUShort (BootSector.SectorsPerFAT);
uint sectorsPerFat32 = bootSector.GetUInt (BootSector.FAT32_SectorPerFAT);
uint totalSectors16 = bootSector.GetUShort (BootSector.TotalSectors);
uint totalSectors32 = bootSector.GetUInt (BootSector.FAT32_TotalSectors);
uint sectorsPerFat = (sectorsPerFat16 != 0) ? sectorsPerFat16 : sectorsPerFat32;
uint fatSectors = nbrFats * sectorsPerFat;
clusterSizeInBytes = sectorsPerCluster * blockSize;
rootDirSectors = (((rootEntries * 32) + (bytesPerSector - 1)) / bytesPerSector);
firstDataSector = reservedSectors + (nbrFats * sectorsPerFat) + rootDirSectors;
if (totalSectors16 != 0)
totalSectors = totalSectors16;
else
totalSectors = totalSectors32;
dataSectors = totalSectors - (reservedSectors + (nbrFats * sectorsPerFat) + rootDirSectors);
totalClusters = dataSectors / sectorsPerCluster;
entriesPerSector = (bytesPerSector / 32);
firstRootDirectorySector = reservedSectors + fatSectors;
dataAreaStart = firstRootDirectorySector + rootDirSectors;
fatStart = reservedSectors;
if (totalClusters < 4085)
fatType = FATType.FAT12;
else if (totalClusters < 65525)
fatType = FATType.FAT16;
else
fatType = FATType.FAT32;
if (fatType == FATType.FAT12) {
reserved = 0xFF0;
last = 0x0FF8;
bad = 0x0FF7;
fatMask = 0xFFFFFFFF;
fatEntries = sectorsPerFat * 3 * blockSize / 2;
}
else if (fatType == FATType.FAT16) {
reserved = 0xFFF0;
last = 0xFFF8;
bad = 0xFFF7;
fatMask = 0xFFFFFFFF;
fatEntries = sectorsPerFat * blockSize / 2;
}
else { // if (type == FatType.FAT32) {
reserved = 0xFFF0;
last = 0x0FFFFFF8;
bad = 0x0FFFFFF7;
fatMask = 0x0FFFFFFF;
fatEntries = sectorsPerFat * blockSize / 4;
}
// some basic checks
if ((nbrFats == 0) || (nbrFats > 2))
valid = false;
else if (totalSectors == 0)
valid = false;
else if (sectorsPerFat == 0)
valid = false;
else if (!((fatType == FATType.FAT12) || (fatType == FATType.FAT16))) // no support for Fat32 yet
valid = false;
else
valid = true;
if (valid) {
base.volumeLabel = bootSector.GetString (fatType != FATType.FAT32 ? BootSector.VolumeLabel : BootSector.FAT32_VolumeLabel, 11);
base.serialNbr = bootSector.GetBytes (fatType != FATType.FAT32 ? BootSector.IDSerialNumber : BootSector.FAT32_IDSerialNumber, 4);
}
return valid;
}