void S9xMainLoop (void)
{
if(ICPU.SavedAtOp)
{
ICPU.SavedAtOp = FALSE;
Registers.PCw = CPU.PBPCAtOpcodeStart;
if(CPU.PCBase)
CPU.Cycles -= CPU.MemSpeed;
goto doOp;
}
for (;;)
{
if (CPU.Flags)
{
if (CPU.Flags & NMI_FLAG)
{
if (Timings.NMITriggerPos <= CPU.Cycles)
{
CPU.Flags &= ~NMI_FLAG;
Timings.NMITriggerPos = 0xffff;
if (CPU.WaitingForInterrupt)
{
CPU.WaitingForInterrupt = FALSE;
Registers.PCw++;
}
S9xOpcode_NMI();
}
}
#ifdef DEBUGGER
if ((CPU.Flags & BREAK_FLAG) && !(CPU.Flags & SINGLE_STEP_FLAG))
{
for (int Break = 0; Break != 6; Break++)
{
if (S9xBreakpoint[Break].Enabled &&
S9xBreakpoint[Break].Bank == Registers.PB &&
S9xBreakpoint[Break].Address == Registers.PCw)
{
if (S9xBreakpoint[Break].Enabled == 2)
S9xBreakpoint[Break].Enabled = TRUE;
else
CPU.Flags |= DEBUG_MODE_FLAG;
}
}
}
#endif
CHECK_SOUND();
if (CPU.Flags & IRQ_FLAG)
{
if (CPU.IRQPending)
// FIXME: In case of IRQ during WRAM refresh
CPU.IRQPending = 0;
else
{
if (CPU.WaitingForInterrupt)
{
CPU.WaitingForInterrupt = FALSE;
Registers.PCw++;
}
if (CPU.IRQActive && !Settings.DisableIRQ)
{
if (!CheckFlag(IRQ))
// in IRQ handler $4211 is supposed to be read, so IRQ_FLAG should be cleared.
S9xOpcode_IRQ();
}
else
CPU.Flags &= ~IRQ_FLAG;
}
}
if (CPU.Flags & SCAN_KEYS_FLAG)
break;
#ifdef DEBUGGER
if (CPU.Flags & DEBUG_MODE_FLAG)
break;
if (CPU.Flags & TRACE_FLAG)
S9xTrace();
if (CPU.Flags & SINGLE_STEP_FLAG)
{
CPU.Flags &= ~SINGLE_STEP_FLAG;
CPU.Flags |= DEBUG_MODE_FLAG;
}
#endif
}
#ifdef CPU_SHUTDOWN
CPU.PBPCAtOpcodeStart = Registers.PBPC;
#endif
doOp:
register uint8 Op;
register struct SOpcodes *Opcodes;
CPU.PrevCycles = CPU.Cycles;
if (CPU.PCBase)
{
Op = CPU.PCBase[Registers.PCw];
CPU.Cycles += CPU.MemSpeed;
Opcodes = ICPU.S9xOpcodes;
}
else
{
Op = S9xGetByte(Registers.PBPC);
OpenBus = Op;
Opcodes = S9xOpcodesSlow;
}
if ((Registers.PCw&MEMMAP_MASK) + ICPU.S9xOpLengths[Op] >= MEMMAP_BLOCK_SIZE)
{
uint8 *oldPCBase = CPU.PCBase;
CPU.PCBase = GetBasePointer(ICPU.ShiftedPB + ((uint16) (Registers.PCw + 4)));
if (oldPCBase!=CPU.PCBase || (Registers.PCw&~MEMMAP_MASK) == (0xffff & ~MEMMAP_MASK))
Opcodes = S9xOpcodesSlow;
}
Registers.PCw++;
(*Opcodes[Op].S9xOpcode)();
if(ICPU.SavedAtOp)
{
ICPU.SavedAtOp = false;
continue;
}
S9xAPUExecute();
if (SA1.Executing)
S9xSA1MainLoop();
while (CPU.Cycles >= CPU.NextEvent)
S9xDoHEventProcessing();
}
S9xPackStatus();
APURegisters.PC = IAPU.PC - IAPU.RAM;
S9xAPUPackStatus();
if (CPU.Flags & SCAN_KEYS_FLAG)
{
#ifdef DEBUGGER
if (!(CPU.Flags & FRAME_ADVANCE_FLAG))
#endif
S9xSyncSpeed();
CPU.Flags &= ~SCAN_KEYS_FLAG;
}
}
void S9xDoHEventProcessing (void)
{
uint8 tmp;
switch (CPU.WhichEvent)
{
case HC_HBLANK_START_EVENT:
if (PPU.HTimerPosition == Timings.HBlankStart)
S9xCheckMissingHTimerPosition();
S9xReschedule();
break;
case HC_HDMA_START_EVENT:
if (PPU.HTimerPosition == Timings.HDMAStart)
S9xCheckMissingHTimerPosition();
S9xReschedule();
if (PPU.HDMA && CPU.V_Counter <= PPU.ScreenHeight)
PPU.HDMA = S9xDoHDMA(PPU.HDMA);
break;
case HC_HCOUNTER_MAX_EVENT:
if (Settings.SuperFX && !SuperFX.oneLineDone && CHECK_EXEC_SUPERFX())
S9xSuperFXExec();
SuperFX.oneLineDone = FALSE; // do this even without SFX
S9xAPUExecute();
CPU.Cycles -= Timings.H_Max;
S9xAPUSetReferenceTime(CPU.Cycles);
if ((Timings.NMITriggerPos != 0xffff) && (Timings.NMITriggerPos >= Timings.H_Max))
Timings.NMITriggerPos -= Timings.H_Max;
CPU.V_Counter++;
if (CPU.V_Counter >= Timings.V_Max) /* V ranges from 0 to Timings.V_Max - 1 */
{
CPU.V_Counter = 0;
Timings.InterlaceField ^= 1;
/* From byuu:
[NTSC]
interlace mode has 525 scanlines: 263 on
the even frame, and 262 on the odd.
non-interlace mode has 524 scanlines:
262 scanlines on both even and odd frames.
[PAL] <PAL info is unverified on hardware>
interlace mode has 625 scanlines: 313 on
the even frame, and 312 on the odd.
non-interlace mode has 624 scanlines:
312 scanlines on both even and odd frames. */
Timings.V_Max = Timings.V_Max_Master; /* 262 (NTSC), 312?(PAL) */
if (IPPU.Interlace && !Timings.InterlaceField)
Timings.V_Max += 1; /* 263 (NTSC), 313?(PAL) */
Memory.FillRAM[0x213F] ^= 0x80;
PPU.RangeTimeOver = 0;
/* FIXME: reading $4210 will wait 2 cycles,
then perform reading, then wait 4 more cycles. */
Memory.FillRAM[0x4210] = MAX_5A22_VERSION;
CPU.Flags &= ~NMI_FLAG;
Timings.NMITriggerPos = 0xffff;
ICPU.Frame++;
PPU.HVBeamCounterLatched = 0;
CPU.Flags |= SCAN_KEYS_FLAG;
}
/* From byuu:
In non-interlace mode, there are 341 dots
per scanline, and 262 scanlines per frame.
On odd frames, scanline 240 is one dot short.
In interlace mode, there are always 341 dots
per scanline. Even frames have 263 scanlines,
and odd frames have 262 scanlines.
Interlace mode scanline 240 on odd frames is
not missing a dot. */
Timings.H_Max = Timings.H_Max_Master; /* HC=1364 */
if (CPU.V_Counter == 240 && !IPPU.Interlace && Timings.InterlaceField) /* V=240 */
Timings.H_Max -= ONE_DOT_CYCLE; /* HC=1360 */
if (CPU.V_Counter != 240 || IPPU.Interlace || !Timings.InterlaceField) /* V=240 */
{
if (Timings.WRAMRefreshPos == SNES_WRAM_REFRESH_HC_v2_MIN_ONE_DOT_CYCLE) /* HC=534 */
Timings.WRAMRefreshPos = SNES_WRAM_REFRESH_HC_v2; /* HC=538 */
else
Timings.WRAMRefreshPos = SNES_WRAM_REFRESH_HC_v2_MIN_ONE_DOT_CYCLE; /* HC=534 */
}
if (PPU.HTimerPosition == 0)
S9xCheckMissingHTimerPosition();
if (CPU.V_Counter == PPU.ScreenHeight + FIRST_VISIBLE_LINE) /* VBlank starts from V=225(240). */
{
S9xEndScreenRefresh();
PPU.HDMA = 0;
/* Bits 7 and 6 of $4212 are computed when read in S9xGetPPU. */
PPU.ForcedBlanking = (Memory.FillRAM[0x2100] >> 7) & 1;
if (!PPU.ForcedBlanking)
{
PPU.OAMAddr = PPU.SavedOAMAddr;
tmp = 0;
if (PPU.OAMPriorityRotation)
tmp = (PPU.OAMAddr & 0xFE) >> 1;
if ((PPU.OAMFlip & 1) || PPU.FirstSprite != tmp)
{
PPU.FirstSprite = tmp;
IPPU.OBJChanged = TRUE;
}
PPU.OAMFlip = 0;
}
/* FIXME: writing to $4210 will wait 6 cycles. */
Memory.FillRAM[0x4210] = 0x80 | MAX_5A22_VERSION;
if (Memory.FillRAM[0x4200] & 0x80)
{
/* FIXME: triggered at HC=6, checked just
before the final CPU cycle, then, when to
call S9xOpcode_NMI()? */
CPU.Flags |= NMI_FLAG;
Timings.NMITriggerPos = 6 + 6;
}
}