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Fixed drive select logic (multiple drives now work properly -- fingers crossed) and some minor cleanup and dead-code removal.

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This commit is contained in:
Josh Dersch
2016-03-24 17:31:21 -07:00
parent bfda781576
commit c4565f81a5
10 changed files with 78 additions and 80 deletions
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63
Contralto/IO/DiskController.cs
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@@ -55,13 +55,25 @@ namespace Contralto.IO
// position is reached (before any data is transferred)."
_dataXfer = (_kAdr & 0x2) != 0x2;
//
// Select disk from bit 14 of KDATA.
// The HW reference claims that the drive is selected by bit 14 of KDATA XOR'd with bit 15
// of KADR but I can find no evidence in the schematics that this is actually so.
// Page 18 of the controller schematic ("DISK ADDRESSING") shows that the current DATA(14) (KDATA bit 14)
// value is gated into the DISK select lines (running to the drive) whenever a KADR<- F1 is executed.
// It is possible that the HW ref is telling the truth but the XORing is done by the Sector Task uCode
// and not the hardware, but where this is actually occurring is not obvious.
// At any rate: The below behavior appears to work correctly, so I'm sticking with it.
//
_disk = ((_kDataWrite & 0x2) >> 1);
Log.Write(LogComponent.DiskController, "KADR set to {0} (Header {1}, Label {2}, Data {3}, Xfer {4}, Drive {5})",
Conversion.ToOctal(_kAdr),
Conversion.ToOctal((_kAdr & 0xc0) >> 6),
Conversion.ToOctal((_kAdr & 0x30) >> 4),
Conversion.ToOctal((_kAdr & 0xc) >> 2),
_dataXfer,
_kAdr & 0x1);
_disk);
Log.Write(LogComponent.DiskController, " -Disk Address ({0}) is C/H/S {1}/{2}/{3}, Drive {4} Restore {5}",
Conversion.ToOctal(_kDataWrite),
@@ -77,7 +89,7 @@ namespace Contralto.IO
{
// Restore operation to cyl. 0:
InitSeek(0);
}
}
}
}
@@ -106,19 +118,7 @@ namespace Contralto.IO
if (_sendAdr & (_kDataWrite & 0x2) != 0)
{
// Select disk if _sendAdr is true
_disk = (_kAdr & 0x1);
_seeking = false;
// Clear the NOTREADY flag depending on whether the drive is loaded or not
if (_drives[_disk].IsLoaded)
{
_kStat &= (ushort)~NOTREADY;
}
else
{
_kStat |= NOTREADY;
}
_seeking = false;
}
}
@@ -214,7 +214,8 @@ namespace Contralto.IO
//
return (_kStat & SECLATE) != 0 ||
(_kStat & SEEKFAIL) != 0 ||
(_kStat & NOTREADY) != 0;
(_kStat & NOTREADY) != 0 ||
(!Ready);
}
}
@@ -279,6 +280,16 @@ namespace Contralto.IO
_kStat = (ushort)((_kStat & 0x0fff) | (_sector << 12));
// Clear the NOTREADY flag depending on whether the selected drive is loaded or not
if (_drives[_disk].IsLoaded)
{
_kStat &= (ushort)~NOTREADY;
}
else
{
_kStat |= NOTREADY;
}
// Reset internal state machine for sector data
_sectorWordIndex = 0;
_syncWordWritten = false;
@@ -397,7 +408,7 @@ namespace Contralto.IO
//
// Set "seek fail" bit based on selected cylinder (if out of bounds) and do not
// commence a seek if so.
if (destCylinder > SelectedDrive.Pack.Geometry.Cylinders - 1)
if (!SelectedDrive.IsLoaded || destCylinder > SelectedDrive.Pack.Geometry.Cylinders - 1)
{
_kStat |= SEEKFAIL;
@@ -703,11 +714,19 @@ namespace Contralto.IO
private bool _debugRead;
// KSTAT bitfields
public static readonly ushort SECLATE = 0x10;
public static readonly ushort NOTREADY = 0x20;
public static readonly ushort STROBE = 0x40;
public static readonly ushort SEEKFAIL = 0x80;
//
// KSTAT bitfields.
// Note that in reality the SECLATE status bit (bit 11) is a bit more nuanced; it's actually the OR of two signals:
// 1) SECLATE while the Sector Task is enabled (meaning that the sector task missed the beginning of a sector and that's bad).
// This is emulated.
// 2) CARRY while the Word Task is enabled. CARRY in this case is the carry out from the disk word shift register, signaling
// a completed word. If the Word Task is still running while a word is completed, this indicates that the word task missed that
// word and that's a fault. This is not currently emulated.
//
public static readonly ushort SECLATE = 0x10; // status bit 11
public static readonly ushort NOTREADY = 0x20; // 10
public static readonly ushort STROBE = 0x40; // 9
public static readonly ushort SEEKFAIL = 0x80; // 8
}
}