Apple-2-Tools
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AppleWin
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LSS simpler impl

This commit is contained in:
tomcw 2023-11-19 21:20:12 +00:00
parent 21dc02dffc
commit 5e9c5fbbab
2 changed files with 132 additions and 27 deletions
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158
source/Disk.cpp
View File

@ -1539,32 +1539,6 @@ void Disk2InterfaceCard::DataLatchReadWOZ(WORD pc, WORD addr, UINT bitCellRemain
#endif
}
void Disk2InterfaceCard::NextFluxData(FloppyDisk& floppy)
{
floppy.m_zeroTickCount = 0;
do
{
BYTE data = floppy.m_trackimage[floppy.m_byte++];
if (floppy.m_byte == floppy.m_nibbles)
floppy.m_byte = 0;
floppy.m_zeroTickCount += data;
if (data != 255)
break;
} while (1);
#if 0
floppy.m_bitCellCount = (floppy.m_zeroTickCount + 0x0f) / 0x20;
#else
UINT zeroTickCount = floppy.m_zeroTickCount;
if ((zeroTickCount & 0x10) == 0) zeroTickCount &= ~0x1f; // round down: if 0x0n, 0x2n, 0x4n etc
else zeroTickCount += 0x1f; // round up: if 0x1n, 0x3n, 0x5n etc
floppy.m_bitCellCount = zeroTickCount / 0x20;
#endif
if (floppy.m_bitCellCount == 0) floppy.m_bitCellCount = 1;
floppy.m_tickCountdown = (floppy.m_bitCellCount > 1) ? 0x20 : floppy.m_zeroTickCount; // last one may be eg. 0x1E,0x20,0x22
_ASSERT(floppy.m_bitCellCount);
}
void Disk2InterfaceCard::NextLSS(BYTE readPulse)
{
// UTAIIe 9-11(Fig 9.8) & 9-14
@ -1588,6 +1562,135 @@ void Disk2InterfaceCard::NextLSS(BYTE readPulse)
m_LSSCode = m_16SectorLSSROM[addr];
}
#if 1
void Disk2InterfaceCard::NextFluxData(FloppyDisk& floppy)
{
floppy.m_zeroTickCount = 0;
do
{
BYTE data = floppy.m_trackimage[floppy.m_byte++];
if (floppy.m_byte == floppy.m_nibbles)
floppy.m_byte = 0;
floppy.m_zeroTickCount += data;
if (data != 255)
break;
} while (1);
SetCountdown(floppy);
}
void Disk2InterfaceCard::SetCountdown(FloppyDisk& floppy)
{
if (floppy.m_zeroTickCount < 0x30)
floppy.m_tickCountdown = floppy.m_zeroTickCount;
else
floppy.m_tickCountdown = 0x20;
}
void Disk2InterfaceCard::DataLatchReadWOZFlux(WORD pc, WORD addr, UINT ticks)
{
FloppyDrive& drive = m_floppyDrive[m_currDrive];
FloppyDisk& floppy = drive.m_disk;
#if _DEBUG
static int dbgWOZ = 0;
if (dbgWOZ)
{
dbgWOZ = 0;
DumpTrackWOZFlux(floppy); // Enable as necessary
}
#endif
for (UINT i = 0; i < ticks; i++)
{
floppy.m_zeroTickCount--;
floppy.m_tickCountdown--;
_ASSERT(floppy.m_zeroTickCount >= 0);
_ASSERT(floppy.m_tickCountdown >= 0);
if (floppy.m_zeroTickCount == 0 || floppy.m_tickCountdown == 0)
{
const BYTE floppyBit = floppy.m_zeroTickCount ? 0 : 1;
if (floppyBit)
{
NextFluxData(floppy);
if (floppy.m_byte == 0)
floppy.m_bitOffset = 0;
}
else
{
SetCountdown(floppy);
}
drive.m_headWindow <<= 1;
drive.m_headWindow |= floppyBit;
m_readPulse = (drive.m_headWindow & 0xf) ? (drive.m_headWindow >> 1) & 1
: (rand() < RAND_THRESHOLD(3, 10)) ? 1 : 0; // ~30% chance of a 1 bit (Ref: WOZ-2.0)
}
m_LSSTicks = (++m_LSSTicks) & 3; // 2MHz clock (= 4x 125ns ticks)
if (m_LSSTicks == 0)
{
NextLSS(m_readPulse);
// NB. Read pulse lasts for one sequencer clock (UTAIIe page 9-29) - ie. 4x 125ns ticks
m_readPulse = 0;
const BYTE code = m_LSSCode & 0x0f;
switch (code)
{
case CLR:
m_shiftReg = 0; break;
case NOP:
break;
case SL0:
m_shiftReg <<= 1; break;
case SL1:
m_shiftReg <<= 1; m_shiftReg |= 1; break;
default:
_ASSERT(0);
}
}
}
m_floppyLatch = m_shiftReg;
}
#else // ----------------------------------------
void Disk2InterfaceCard::NextFluxData(FloppyDisk& floppy)
{
floppy.m_zeroTickCount = 0;
do
{
BYTE data = floppy.m_trackimage[floppy.m_byte++];
if (floppy.m_byte == floppy.m_nibbles)
floppy.m_byte = 0;
floppy.m_zeroTickCount += data;
if (data != 255)
break;
} while (1);
#if 0
if ((floppy.m_zeroTickCount & 3) >= 2)
floppy.m_zeroTickCount += 2;
floppy.m_zeroTickCount &= ~3;
#endif
#if 0
floppy.m_bitCellCount = (floppy.m_zeroTickCount + 0x0f) / 0x20;
#else
UINT zeroTickCount = floppy.m_zeroTickCount;
if ((zeroTickCount & 0x10) == 0) zeroTickCount &= ~0x1f; // round down: if 0x0n, 0x2n, 0x4n etc
else zeroTickCount += 0x1f; // round up: if 0x1n, 0x3n, 0x5n etc
floppy.m_bitCellCount = zeroTickCount / 0x20;
#endif
if (floppy.m_bitCellCount == 0) floppy.m_bitCellCount = 1;
floppy.m_tickCountdown = (floppy.m_bitCellCount > 1) ? 0x20 : floppy.m_zeroTickCount; // last one may be eg. 0x1E,0x20,0x22
_ASSERT(floppy.m_bitCellCount);
}
void Disk2InterfaceCard::DataLatchReadWOZFlux(WORD pc, WORD addr, UINT ticks)
{
#if LOG_DISK_NIBBLES_READ
@ -1641,7 +1744,7 @@ void Disk2InterfaceCard::DataLatchReadWOZFlux(WORD pc, WORD addr, UINT ticks)
oldFlag = true;
}
#if 1
#if 0
m_LSSTicks = (++m_LSSTicks) & 3; // 2MHz clock (= 4x 125ns ticks)
if (m_LSSTicks == 0)
{
@ -1734,6 +1837,7 @@ void Disk2InterfaceCard::DataLatchReadWOZFlux(WORD pc, WORD addr, UINT ticks)
}
}
#endif
void Disk2InterfaceCard::DataLoadWriteWOZ(WORD pc, WORD addr, UINT bitCellRemainder)
{

1
source/Disk.h
View File

@ -222,6 +222,7 @@ private:
__forceinline void IncBitStream(FloppyDisk& floppy);
void NextFluxData(FloppyDisk& floppy);
void NextLSS(BYTE readPulse);
void SetCountdown(FloppyDisk& floppy);
void DataLatchReadWOZ(WORD pc, WORD addr, UINT bitCellRemainder);
void DataLatchReadWOZFlux(WORD pc, WORD addr, UINT ticks);
void DataLoadWriteWOZ(WORD pc, WORD addr, UINT bitCellRemainder);