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Fix FindSeamWOZ()

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This commit is contained in:
tomcw 2022-09-16 21:44:22 +01:00
parent 85c31d2a8b
commit 666827c776
1 changed files with 34 additions and 35 deletions
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69
source/Disk.cpp
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@ -1550,7 +1550,6 @@ void Disk2InterfaceCard::DataShiftWriteWOZ(WORD pc, WORD addr, ULONG uExecutedCy
void Disk2InterfaceCard::FindSeamWOZ(FloppyDisk floppy, float track) // pass a copy of m_floppy void Disk2InterfaceCard::FindSeamWOZ(FloppyDisk floppy, float track) // pass a copy of m_floppy
{ {
BYTE shiftReg = 0; BYTE shiftReg = 0;
BYTE prevShiftReg = 0;
UINT zeroCount = 0; UINT zeroCount = 0;
int startBitOffset = -1; // NB. change this to start of first FF/10 int startBitOffset = -1; // NB. change this to start of first FF/10
@ -1560,7 +1559,6 @@ void Disk2InterfaceCard::FindSeamWOZ(FloppyDisk floppy, float track) // pass a c
const UINT remainder = 7 - (floppy.m_bitOffset & 7); const UINT remainder = 7 - (floppy.m_bitOffset & 7);
floppy.m_bitMask = 1 << remainder; floppy.m_bitMask = 1 << remainder;
int prevNibbleStartBitOffset = -1;
int nibbleStartBitOffset = -1; int nibbleStartBitOffset = -1;
int syncFFStartBitOffset = -1; int syncFFStartBitOffset = -1;
int syncFFRunLength = 0; int syncFFRunLength = 0;
@ -1577,47 +1575,48 @@ void Disk2InterfaceCard::FindSeamWOZ(FloppyDisk floppy, float track) // pass a c
if ((startBitOffset < 0 && floppy.m_bitOffset == 0) || (startBitOffset == floppy.m_bitOffset)) // done complete track? if ((startBitOffset < 0 && floppy.m_bitOffset == 0) || (startBitOffset == floppy.m_bitOffset)) // done complete track?
break; break;
if (shiftReg == 0 && outputBit == 0) if (shiftReg & 0x80)
{ {
zeroCount++; if (outputBit == 0) // zero, so LSS holds nibble in latch
continue; {
} zeroCount++;
continue;
}
if (nibbleStartBitOffset < 0) // else: start of next nibble
prevNibbleStartBitOffset = nibbleStartBitOffset = floppy.m_bitOffset;
if (shiftReg == 0xff && zeroCount == 2)
{
if (startBitOffset < 0)
startBitOffset = nibbleStartBitOffset;
if (syncFFStartBitOffset < 0)
syncFFStartBitOffset = nibbleStartBitOffset;
syncFFRunLength++;
}
if ((shiftReg != 0xff || zeroCount != 2) && syncFFStartBitOffset >= 0)
{
if (longestSyncFFRunLength < syncFFRunLength)
{
longestSyncFFStartBitOffset = syncFFStartBitOffset;
longestSyncFFRunLength = syncFFRunLength;
syncFFStartBitOffset = -1;
syncFFRunLength = 0;
}
}
shiftReg = 0;
zeroCount = 0;
}
shiftReg <<= 1; shiftReg <<= 1;
shiftReg |= outputBit; shiftReg |= outputBit;
if ((shiftReg & 0x80) == 0) if (shiftReg == 0x01)
continue;
if (prevShiftReg == 0xff && zeroCount == 2)
{ {
if (startBitOffset < 0) nibbleStartBitOffset = floppy.m_bitOffset - 1;
startBitOffset = prevNibbleStartBitOffset; if (nibbleStartBitOffset < 0) nibbleStartBitOffset += floppy.m_bitCount;
if (syncFFStartBitOffset < 0)
syncFFStartBitOffset = prevNibbleStartBitOffset;
syncFFRunLength++;
} }
if ((prevShiftReg != 0xff || zeroCount != 2) && syncFFStartBitOffset >= 0)
{
if (longestSyncFFRunLength < syncFFRunLength)
{
longestSyncFFStartBitOffset = syncFFStartBitOffset;
longestSyncFFRunLength = syncFFRunLength;
syncFFStartBitOffset = -1;
syncFFRunLength = 0;
}
}
prevNibbleStartBitOffset = nibbleStartBitOffset;
nibbleStartBitOffset = -1;
prevShiftReg = shiftReg;
shiftReg = 0;
zeroCount = 0;
} }
if (longestSyncFFRunLength) if (longestSyncFFRunLength)