/// <summary>
/// Hardware reset of the card
/// </summary>
public void Reset()
{
// reset card
m_reg_page = 0;
m_reg_param = 0;
m_fdc_reset_state = true;
m_current_drive_index = 0;
// reset FDC1793
m_fdc_status = 0;
m_fdc_status_mode = 1;
m_fdc_command = 0;
m_fdc_track = 0;
m_fdc_sector = 0;
m_fdc_data = 0;
m_fdc_last_step_direction = 0;
m_head_loaded = false;
m_data_count = 0;
m_data_length = 0;
m_operation_state = OperationState.None;
}
/** Write1793() **********************************************/
/** Write value V into WD1793 register A. Returns DRQ/IRQ **/
/** values. **/
/*************************************************************/
public void PortWrite(ushort in_address, byte in_value)
{
if ((in_address & 0x0f) != 8)
{
if ((in_address & 0x0f) == 3)
{
//Debug.Write(in_value.ToString("X2") + " ");
}
else
{
Debug.Write((in_address & 0x0f).ToString("X2") + ":" + in_value.ToString("X2") + " = ");
}
}
switch (in_address & 0x0f)
{
// command address
case PORT_COMMAND:
m_fdc_command = in_value;
// Reset interrupt request
m_reg_hw_status &= ~(HardwareFlags.INT);
// If it is FORCE-IRQ command...
if ((in_value & 0xF0) == 0xD0)
{
m_force_interrupt = (ForceInterruptFlags)(in_value & 0x0f);
Debug.WriteLine("Force interrupt: {0}", m_force_interrupt);
// Reset any executing command
m_data_length = 0;
m_data_count = 0;
m_operation_state = OperationState.None;
// Either reset BUSY flag or reset all flags if BUSY=0
if ((m_fdc_status & StatusFlags.BUSY) != 0)
{
m_fdc_status &= ~StatusFlags.BUSY;
}
else
{
m_fdc_status = m_disk_drives[m_current_drive_index].Track == 0 ? StatusFlags.TRACK0 : 0;
m_fdc_status_mode = 1;
}
// Cause immediate interrupt if requested
if ((in_value & (byte)CommandFlags.IRQ) != 0)
{
m_reg_hw_status = HardwareFlags.INT;
}
// Done
return;
}
// If busy, drop out
if ((m_fdc_status & StatusFlags.BUSY) != 0)
{
break;
}
// Reset status register
m_fdc_status = 0x00;
m_reg_hw_status = 0x00;
// Depending on the command...
switch (in_value & 0xF0)
{
// RESTORE (seek track 0)
case 0x00:
Debug.WriteLine("Restore");
// command group I
m_fdc_status_mode = 1;
// set head load
m_head_loaded = ((in_value & (byte)CommandFlags.LOADHEAD) != 0);
m_fdc_last_step_direction = 0;
// if already at track zero
if (m_disk_drives[m_current_drive_index].Track == 0)
{
m_fdc_status |= StatusFlags.TRACK0;
m_reg_hw_status |= HardwareFlags.INT;
m_fdc_track = 0;
m_operation_state = OperationState.None;
}
else
{
// not on the first track -> start operation
StartOperation((m_disk_drives[m_current_drive_index].Geometry.NumberOfTracks / 2) * SteppingDelays[in_value & (byte)CommandFlags.STEPRATE], StatusFlags.TRACK0 | (StatusFlags)(((in_value & (byte)CommandFlags.LOADHEAD) != 0) ? StatusFlags.HEADLOAD : 0), HardwareFlags.INT, 0);
}
break;
// SEEK command
case 0x10:
Debug.WriteLine("Seek: {0:x2}", m_fdc_data);
// command group I
m_fdc_status_mode = 1;
// set head load
m_head_loaded = ((in_value & (byte)CommandFlags.LOADHEAD) != 0);
if (m_fdc_data > m_fdc_track)
{
m_fdc_last_step_direction = 0;
}
else
{
m_fdc_last_step_direction = 0x20;
}
// Reset any executing command
m_data_count = 0;
m_data_length = 0;
StartOperation(Math.Abs((int)m_fdc_data - (int)m_fdc_track) * SteppingDelays[in_value & (byte)CommandFlags.STEPRATE], (StatusFlags)(((in_value & (byte)CommandFlags.LOADHEAD) != 0) ? StatusFlags.HEADLOAD : 0), HardwareFlags.INT, m_fdc_data);
break;
case 0x20: // STEP
case 0x30: // STEP-AND-UPDATE
case 0x40: // STEP-IN
case 0x50: // STEP-IN-AND-UPDATE
case 0x60: // STEP-OUT
case 0x70: // STEP-OUT-AND-UPDATE
{
Debug.Write(string.Format("Step: {0:x2}", (in_value & 0xF0)));
// command group I
m_fdc_status_mode = 1;
// set head load
m_head_loaded = ((in_value & (byte)CommandFlags.LOADHEAD) != 0);
// Either store or fetch step direction
if ((in_value & 0x40) != 0)
{
m_fdc_last_step_direction = (byte)(in_value & 0x20);
}
else
{
in_value = (byte)((in_value & ~0x20) | m_fdc_last_step_direction);
}
// Step the head, update track register if requested
byte target_track = m_disk_drives[m_current_drive_index].Track;
if ((in_value & 0x20) != 0)
{
if (m_disk_drives[m_current_drive_index].Track > 0)
{
target_track--;
}
}
else
{
if (target_track < m_disk_drives[m_current_drive_index].Geometry.NumberOfTracks - 1)
{
target_track++;
}
}
Debug.WriteLine(" Track: {0}", target_track);
//m_disk_drives[m_current_drive_index].Track = target_track;
// Update track register if requested
StatusFlags new_status = 0;
if ((in_value & (byte)CommandFlags.SETTRACK) != 0)
{
if (target_track >= m_disk_drives[m_current_drive_index].Geometry.NumberOfTracks)
{
new_status = StatusFlags.SEEKERR;
}
m_fdc_track = m_disk_drives[m_current_drive_index].Track;
}
StartOperation(SteppingDelays[in_value & (byte)CommandFlags.STEPRATE], new_status, HardwareFlags.INT, target_track);
}
break;
// Track write
case 0xF0:
Debug.Write("TrackWrite ");
// command group III
m_fdc_status_mode = 3;
m_operation_start_tick = m_tvcomputer.GetCPUTicks();
m_operation_state = OperationState.TrackWriteWaitForIndex;
m_prev_index_pulse_state = IsIndexPulse();
m_fdc_status = StatusFlags.BUSY;
m_reg_hw_status = HardwareFlags.DRQ;
break;
// Sector read
case 0x80: // single sector read
case 0x90: // multiple sector read
Debug.WriteLine("Sector read, T:{0:d}, S:{1:d}, H:{2:d}", m_fdc_track, m_fdc_sector, GetCurrentDriveSide());
// check drive
if (m_current_drive_index == InvalidDriveIndex || !m_disk_drives[m_current_drive_index].IsDiskPresent())
{
m_fdc_status = StatusFlags.NOTREADY;
}
else
{
// check sector and track address
if (m_fdc_track != m_disk_drives[m_current_drive_index].Track || m_fdc_sector <1 || m_fdc_sector> m_disk_drives[m_current_drive_index].Geometry.SectorPerTrack)
{
m_fdc_status = StatusFlags.NOTFOUND;
m_reg_hw_status = HardwareFlags.INT;
m_operation_state = OperationState.None;
m_fdc_status_mode = 2;
m_data_length = 0;
}
else
{
m_disk_drives[m_current_drive_index].Track = m_fdc_track;
m_data_count = 0;
m_data_length = m_disk_drives[m_current_drive_index].Geometry.SectorLength * (((in_value & 0x10) != 0) ? m_disk_drives[m_current_drive_index].Geometry.SectorPerTrack - m_fdc_sector + 1 : 1);
m_operation_start_tick = m_tvcomputer.GetCPUTicks();
m_operation_state = OperationState.SectorRead;
m_fdc_status = StatusFlags.BUSY;
m_fdc_status_mode = 2;
m_head_loaded = true;
m_disk_drives[m_current_drive_index].SeekSector(m_fdc_sector, GetCurrentDriveSide());
}
}
break;
#if false
case 0xA0:
case 0xB0: /* WRITE-SECTORS */
if (D->Verbose)
{
printf("WD1793: WRITE-SECTOR%s %c:%d:%d:%d (%02Xh)\n", V & 0x10 ? "S" : "", 'A' + D->Drive, D->Side, D->R[1], D->R[2], V);
}
/* Seek to the requested sector */
D->Ptr = SeekFDI(
D->Disk[D->Drive], D->Side, D->Track[D->Drive],
V & C_SIDECOMP ? !!(V & C_SIDE) : D->Side, D->R[1], D->R[2]
);
/* If seek successful, set up writing operation */
if (!D->Ptr)
{
if (D->Verbose)
{
printf("WD1793: WRITE ERROR\n");
}
D->R[0] = (D->R[0] & ~F_ERRCODE) | F_NOTFOUND;
m_irq_pending = true;;
}
else
{
m_wr_length = D->Disk[D->Drive]->SecSize
* (V & 0x10 ? (D->Disk[D->Drive]->Sectors - D->R[2] + 1) : 1);
D->R[0] |= F_BUSY | F_DRQ;
D->IRQ = WD1793_DRQ;
D->Wait = 255;
}
break;
#endif
// Read address
case 0xC0:
Debug.WriteLine("Read address", in_value);
m_crc_generator.Reset();
m_address_buffer[0] = GetCurrentDriveTrack();
m_address_buffer[1] = GetCurrentDriveSide();
m_address_buffer[2] = 1;
m_address_buffer[3] = GetCurrentSectorLength();
m_crc_generator.Add(m_address_buffer, 4);
m_address_buffer[4] = m_crc_generator.CRCLow;
m_address_buffer[5] = m_crc_generator.CRCHigh;
m_data_count = 0;
m_data_length = 6;
m_fdc_sector = GetCurrentDriveTrack();
m_prev_index_pulse_state = IsIndexPulse();
m_operation_state = OperationState.IDReadWaitForIndex;
m_fdc_status_mode = 3;
m_head_loaded = true;
break;
#if false
/* Read first sector address from the track */
if (!D->Disk[D->Drive])
{
D->Ptr = 0;
}
else
{
for (J = 0; J < 256; ++J)
{
D->Ptr = SeekFDI(
D->Disk[D->Drive],
D->Side, D->Track[D->Drive],
D->Side, D->Track[D->Drive], J
);
if (D->Ptr)
{
break;
}
}
}
/* If address found, initiate data transfer */
if (!D->Ptr)
{
if (D->Verbose)
{
printf("WD1793: READ-ADDRESS ERROR\n");
}
D->R[0] |= F_NOTFOUND;
m_irq_pending = true;;
}
else
{
D->Ptr = D->Disk[D->Drive]->Header;
m_rd_length = 6;
D->R[0] |= F_BUSY | F_DRQ;
D->IRQ = WD1793_DRQ;
D->Wait = 255;
}
break;
#endif
#if false
case 0xE0: /* READ-TRACK */
if (D->Verbose)
{
printf("WD1793: READ-TRACK %d (%02Xh) UNSUPPORTED!\n", D->R[1], V);
}
break;
case 0xF0: /* WRITE-TRACK */
if (D->Verbose)
{
printf("WD1793: WRITE-TRACK %d (%02Xh) UNSUPPORTED!\n", D->R[1], V);
}
break;
default: /* UNKNOWN */
if (D->Verbose)
{
printf("WD1793: UNSUPPORTED OPERATION %02Xh!\n", V);
}
break;
#endif
}
break;
// track register
case PORT_TRACK:
Debug.WriteLine("Track register set: {0:x2}", in_value);
if ((m_fdc_status & StatusFlags.BUSY) == 0 && !m_fdc_reset_state)
{
m_fdc_track = in_value;
}
break;
// sector register
case PORT_SECTOR:
Debug.WriteLine("Sector register set: {0:x2}", in_value);
if ((m_fdc_status & StatusFlags.BUSY) == 0 && !m_fdc_reset_state)
{
m_fdc_sector = in_value;
}
break;
case PORT_DATA:
m_fdc_data = in_value;
switch (m_operation_state)
{
case OperationState.TrackWriteGap:
m_track_write_id_buffer = (m_track_write_id_buffer << 8) | in_value;
break;
}
m_reg_hw_status &= ~HardwareFlags.DRQ;
/*
* if ((m_reg_hw_status & HardwareFlags.DRQ) == 0)
* {
* m_track_write_id_buffer = (m_track_write_id_buffer << 8) | in_value;
* }
* else
* {
* // data overrun occured
* m_reg_hw_status = HardwareFlags.INT;
* m_fdc_status |= StatusFlags.LOSTDATA;
* m_operation_state = OperationState.None;
* }
*/
break;
#if false
// check track write mode
if (m_read_write_mode != ReadWriteMode.TrackWrite)
{
TrackWriteData(in_value);
}
else
{
/* When writing data, store value to disk */
if (m_wr_length > 0)
{
Debug.WriteLine(string.Format("WD1793: EXTRA DATA WRITE (%02Xh)\n", in_value));
}
else
{
/* Write data */
*D->Ptr++ = V;
/* Decrement length */
if (--m_wr_length > 0)
{
/* Reset timeout watchdog */
D->Wait = 255;
/* Advance to the next sector as needed */
if (!(m_wr_length & (D->Disk[D->Drive]->SecSize - 1)))
{
++D->R[2];
}
}
else
{
/* Write completed */
if (D->Verbose)
{
printf("WD1793: WRITE COMPLETED\n");
}
D->R[0] &= ~(F_DRQ | F_BUSY);
m_irq_pending = true;;
}
}
}
// Save last written value
m_fdc_data = in_value;
#endif
// parameter register
case PORT_PARAM:
Debug.WriteLine("Param register set: {0}", (ParametersFlags)in_value);
m_reg_param = (ParametersFlags)in_value;
switch (m_reg_param & ParametersFlags.DriveSelectMask)
{
case ParametersFlags.DriveSelect0:
m_current_drive_index = 0;
break;
case ParametersFlags.DriveSelect1:
m_current_drive_index = 1;
break;
case ParametersFlags.DriveSelect2:
m_current_drive_index = 2;
break;
case ParametersFlags.DriveSelect3:
m_current_drive_index = 3;
break;
default:
m_current_drive_index = InvalidDriveIndex;
break;
}
break;
// page register
case PORT_PAGE:
m_reg_page = in_value;
m_fdc_reset_state = false;
break;
}
}
