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Refactor: consolidate 'modechanging' optimisations into a single function

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This commit is contained in:
tomcw 2018-11-10 10:30:19 +00:00
parent 42c58f54e7
commit 6fb5b3b0e8
3 changed files with 36 additions and 37 deletions
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18
source/LanguageCard.cpp
View File

@ -85,22 +85,8 @@ BYTE __stdcall LanguageCardUnit::IO(WORD PC, WORD uAddr, BYTE bWrite, BYTE uValu
//
if (IS_APPLE2E)
{
// IF THE EMULATED PROGRAM HAS JUST UPDATED THE MEMORY WRITE MODE AND IS
// ABOUT TO UPDATE THE MEMORY READ MODE, HOLD OFF ON ANY PROCESSING UNTIL
// IT DOES SO.
//
// NB. A 6502 interrupt occurring between these memory write & read updates could lead to incorrect behaviour.
// - although any data-race is probably a bug in the 6502 code too.
if ((PC < 0xC000) &&
(((*(LPDWORD)(mem+PC) & 0x00FFFEFF) == 0x00C0048D) || // Next: STA $C004 or STA $C005
((*(LPDWORD)(mem+PC) & 0x00FFFEFF) == 0x00C0028D))) // Next: STA $C002 or STA $C003
{
SetModeChanging(1);
return bWrite ? 0 : MemReadFloatingBus(nExecutedCycles);
}
}
if (MemOptimizeForModeChanging(PC, uAddr))
return bWrite ? 0 : MemReadFloatingBus(nExecutedCycles);
// IF THE MEMORY PAGING MODE HAS CHANGED, UPDATE OUR MEMORY IMAGES AND
// WRITE TABLES.

53
source/Memory.cpp
View File

@ -972,11 +972,6 @@ static bool IsCardInSlot(const UINT uSlot)
//===========================================================================
void SetModeChanging(BOOL value)
{
modechanging = value;
}
DWORD GetMemMode(void)
{
return memmode;
@ -1953,21 +1948,8 @@ BYTE __stdcall MemSetPaging(WORD programcounter, WORD address, BYTE write, BYTE
}
}
if (IS_APPLE2E)
{
// IF THE EMULATED PROGRAM HAS JUST UPDATED THE MEMORY WRITE MODE AND IS
// ABOUT TO UPDATE THE MEMORY READ MODE, HOLD OFF ON ANY PROCESSING UNTIL
// IT DOES SO.
//
// NB. A 6502 interrupt occurring between these memory write & read updates could lead to incorrect behaviour.
// - although any data-race is probably a bug in the 6502 code too.
if ((address >= 4) && (address <= 5) &&
((*(LPDWORD)(mem+programcounter) & 0x00FFFEFF) == 0x00C0028D)) // Next: STA $C002 or STA $C003
{
modechanging = 1;
return 0; // For $C004 & $C005: entry to this func is always via a write to $C004 or $C005
}
}
if (MemOptimizeForModeChanging(programcounter, address))
return write ? 0 : MemReadFloatingBus(nExecutedCycles);
// IF THE MEMORY PAGING MODE HAS CHANGED, UPDATE OUR MEMORY IMAGES AND
// WRITE TABLES.
@ -2012,6 +1994,37 @@ BYTE __stdcall MemSetPaging(WORD programcounter, WORD address, BYTE write, BYTE
//===========================================================================
bool MemOptimizeForModeChanging(WORD programcounter, WORD address)
{
if (IS_APPLE2E)
{
// IF THE EMULATED PROGRAM HAS JUST UPDATED THE MEMORY WRITE MODE AND IS
// ABOUT TO UPDATE THE MEMORY READ MODE, HOLD OFF ON ANY PROCESSING UNTIL
// IT DOES SO.
//
// NB. A 6502 interrupt occurring between these memory write & read updates could lead to incorrect behaviour.
// - although any data-race is probably a bug in the 6502 code too.
if ((address >= 4) && (address <= 5) && // Now: RAMWRTOFF or RAMWRTON
((*(LPDWORD)(mem+programcounter) & 0x00FFFEFF) == 0x00C0028D)) // Next: STA $C002(RAMRDOFF) or STA $C003(RAMRDON)
{
modechanging = 1;
return true;
}
if ((address >= 0x80) && (address <= 0x8F) && (programcounter < 0xC000) && // Now: LC
(((*(LPDWORD)(mem+programcounter) & 0x00FFFEFF) == 0x00C0048D) || // Next: STA $C004(RAMWRTOFF) or STA $C005(RAMWRTON)
((*(LPDWORD)(mem+programcounter) & 0x00FFFEFF) == 0x00C0028D))) // or STA $C002(RAMRDOFF) or STA $C003(RAMRDON)
{
modechanging = 1;
return true;
}
}
return false;
}
//===========================================================================
LPVOID MemGetSlotParameters(UINT uSlot)
{
_ASSERT(uSlot < NUM_SLOTS);

2
source/Memory.h
View File

@ -66,7 +66,7 @@ LPBYTE MemGetBankPtr(const UINT nBank);
LPBYTE MemGetCxRomPeripheral();
DWORD GetMemMode(void);
void SetMemMode(DWORD memmode);
void SetModeChanging(BOOL value);
bool MemOptimizeForModeChanging(WORD programcounter, WORD address);
bool MemIsAddrCodeMemory(const USHORT addr);
void MemInitialize ();
void MemInitializeROM(void);