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WL: insert an extra 0-bit (2 methods)

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This commit is contained in:
tomcw 2020-01-21 08:41:48 +00:00
parent af720f7352
commit e9c7d6bb0f
2 changed files with 42 additions and 5 deletions
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30
source/Disk.cpp
View File

@ -1073,7 +1073,7 @@ void __stdcall Disk2InterfaceCard::DataLatchReadWriteWOZ(WORD pc, WORD addr, BYT
// The first 1-bit will produce a latch nibble, and this 1-bit is unlikely to be the nibble's high bit.
// So we need to ensure we run enough bits through the sequencer to re-sync.
// NB. For Planetfall 13 bitcells(NG) / 14 bitcells(OK)
const UINT significantBitCells = 50; // 5x 10-bit sync FF nibbles
const UINT significantBitCells = floppy.m_bitCount;
UINT bitCellDelta = GetBitCellDelta(ImageGetOptimalBitTiming(floppy.m_imagehandle));
UINT bitCellRemainder;
@ -1113,6 +1113,8 @@ void __stdcall Disk2InterfaceCard::DataLatchReadWriteWOZ(WORD pc, WORD addr, BYT
FrameDrawDiskStatus((HDC)0);
}
static int g_zeroFieldFlag = 1;
static int g_zeroFieldCount = 0;
void Disk2InterfaceCard::DataLatchReadWOZ(WORD pc, WORD addr, UINT bitCellRemainder)
{
// m_diskLastReadLatchCycle = g_nCumulativeCycles; // Not used by WOZ (only by NIB)
@ -1136,7 +1138,7 @@ void Disk2InterfaceCard::DataLatchReadWOZ(WORD pc, WORD addr, UINT bitCellRemain
#endif
// Only extraCycles of 2 & 3 can hold the latch for another bitCell period, eg. m_latchDelay: 3->5 or 7->9
UINT extraLatchDelay = ((UINT)floppy.m_extraCycles >= 2) ? 2 : 0; // GH#733 (0,1->0; 2,3->2)
// UINT extraLatchDelay = ((UINT)floppy.m_extraCycles >= 2) ? 2 : 0; // GH#733 (0,1->0; 2,3->2)
for (UINT i = 0; i < bitCellRemainder; i++)
{
@ -1147,6 +1149,23 @@ void Disk2InterfaceCard::DataLatchReadWOZ(WORD pc, WORD addr, UINT bitCellRemain
BYTE outputBit = (drive.m_headWindow & 0xf) ? (drive.m_headWindow >> 1) & 1
: (rand() < ((RAND_MAX * 3) / 10)) ? 1 : 0; // ~30% chance of a 1 bit (Ref: WOZ-2.0)
#if 0 // DEBUG: insert an extra 0-bit into the field of 317 zero bits
bool doInc = true;
if (drive.m_phase == 0 && floppy.m_bitOffset == (0x5811 + 92))
{
g_zeroFieldCount++;
if (regs.pc < 0x8ff)
{
if (g_zeroFieldFlag)
{
g_zeroFieldFlag = 0;
doInc = false;
}
}
}
if (doInc)
#endif
{
floppy.m_bitMask >>= 1;
if (!floppy.m_bitMask)
{
@ -1161,6 +1180,7 @@ void Disk2InterfaceCard::DataLatchReadWOZ(WORD pc, WORD addr, UINT bitCellRemain
floppy.m_bitOffset = 0;
floppy.m_byte = 0;
}
}
if (m_resetSequencer)
{
@ -1175,9 +1195,9 @@ void Disk2InterfaceCard::DataLatchReadWOZ(WORD pc, WORD addr, UINT bitCellRemain
if (m_latchDelay)
{
if (i == bitCellRemainder-1) // On last bitCell
m_latchDelay += extraLatchDelay; // +0 or +2
extraLatchDelay = 0; // and always clear (even when not last bitCell)
// if (i == bitCellRemainder-1) // On last bitCell
// m_latchDelay += extraLatchDelay; // +0 or +2
// extraLatchDelay = 0; // and always clear (even when not last bitCell)
m_latchDelay -= 4;
if (m_latchDelay < 0)

17
source/DiskImageHelper.cpp
View File

@ -1190,6 +1190,23 @@ public:
return ReadEmptyTrack(pTrackImageBuffer, pNibbles, pBitCount); // TODO: Enlarge track buffer, but for now just return an empty track
memcpy(pTrackImageBuffer, &pImageInfo->pImageBuffer[pTRK->startBlock*CWOZHelper::BLOCK_SIZE], *pNibbles);
#if 0 // DEBUG: insert an extra 0-bit into the field of 317 zero bits
if (phase == 0)
{
UINT offset = 0x5870/8; //0x5811 + 92 = 0x586D
BYTE c = 0;
while (offset < (UINT)*pNibbles)
{
BYTE d = pTrackImageBuffer[offset];
BYTE n = (c<<7) | (d>>1);
c = d&1;
pTrackImageBuffer[offset] = n;
offset++;
}
(*pBitCount)++;
*pNibbles = (pTRK->bitCount+7) / 8;
}
#endif
}
virtual void Write(ImageInfo* pImageInfo, const float phase, LPBYTE pTrackImageBuffer, int nNibbles)