Introduce new APU timing hack

Timings.APUAllowTimeOverflow allows the SPC to cross the time limit
set by CPU.Cycles. Currently fixes Earthworm Jim 2, Ms. Pacman and
NBA Hang Time.

source/snes9x/apu/SNES_SPC.cpp

@@ -511,7 +511,7 @@ int SNES_SPC::cpu_read( int addr, rel_time_t time )
 BOOST::uint8_t* SNES_SPC::run_until_( time_t end_time )\
 {\
 	rel_time_t rel_time = m.spc_time - end_time;\
-	assert( rel_time <= 0 );\
+	/*assert( rel_time <= 0 );*/\
 	m.spc_time = end_time;\
 	m.dsp_time += rel_time;\
 	m.timers [0].next_time += rel_time;\
@@ -524,7 +524,7 @@ BOOST::uint8_t* SNES_SPC::run_until_( time_t end_time )\
 	m.timers [0].next_time -= rel_time;\
 	m.timers [1].next_time -= rel_time;\
 	m.timers [2].next_time -= rel_time;\
-	assert( m.spc_time <= end_time );\
+	/*assert( m.spc_time >= end_time );*/\
 	return &REGS [r_cpuio0];\
 }
 
@@ -543,7 +543,7 @@ void SNES_SPC::end_frame( time_t end_time )
 	// Greatest number of clocks early that emulation can stop early due to
 	// not being able to execute current instruction without going over
 	// allowed time.
-	assert( -cpu_lag_max <= m.spc_time && m.spc_time <= 0 );
+	assert( -cpu_lag_max <= m.spc_time && m.spc_time <= cpu_lag_max );
 	
 	// Catch timers up to CPU
 	for ( int i = 0; i < timer_count; i++ )

source/snes9x/apu/SNES_SPC.h

@@ -106,6 +106,8 @@ public:
 
 //// Snes9x Accessor
 
+	void	spc_allow_time_overflow( bool );
+
 	void    dsp_set_spc_snapshot_callback( void (*callback) (void) );
 	void    dsp_dump_spc_snapshot( void );
 	void    dsp_set_stereo_switch( int );
@@ -258,6 +260,9 @@ private:
 	static char const signature [signature_size + 1];
 	
 	void save_regs( uint8_t out [reg_count] );
+
+// Snes9x timing hack
+	bool allow_time_overflow;
 };
 
 #include <assert.h>
@@ -285,4 +290,6 @@ inline void SNES_SPC::disable_surround( bool disable ) { dsp.disable_surround( d
 inline bool SNES_SPC::check_kon() { return dsp.check_kon(); }
 #endif
 
+inline void SNES_SPC::spc_allow_time_overflow( bool allow ) { allow_time_overflow = allow; }
+
 #endif

source/snes9x/apu/SNES_SPC_misc.cpp

@@ -69,6 +69,8 @@ blargg_err_t SNES_SPC::init()
 		m.cycle_table [i * 2 + 1] = n & 0x0F;
 	}
 
+	allow_time_overflow = false;
+	
 	#if SPC_LESS_ACCURATE
 		memcpy( reg_times, reg_times_, sizeof reg_times );
 	#endif

source/snes9x/apu/SPC_CPU.h

@@ -196,7 +196,9 @@ loop:
 	check( (unsigned) y < 0x100 );
 	
 	opcode = *pc;
-	if ( (rel_time += m.cycle_table [opcode]) > 0 )
+	if (allow_time_overflow && rel_time >= 0 )
+		goto stop;
+	if ( (rel_time += m.cycle_table [opcode]) > 0 && !allow_time_overflow)
 		goto out_of_time;
 	
 	#ifdef SPC_CPU_OPCODE_HOOK

source/snes9x/apu/apu.cpp

@@ -598,6 +598,11 @@ void S9xAPUTimingSetSpeedup (int ticks)
 	UpdatePlaybackRate();
 }
 
+void S9xAPUAllowTimeOverflow (bool allow)
+{
+	spc_core->spc_allow_time_overflow(allow);
+}
+
 void S9xResetAPU (void)
 {
 	spc::reference_time = 0;

source/snes9x/apu/apu.h

@@ -195,6 +195,7 @@ void S9xAPUExecute (void);
 void S9xAPUEndScanline (void);
 void S9xAPUSetReferenceTime (int32);
 void S9xAPUTimingSetSpeedup (int);
+void S9xAPUAllowTimeOverflow (bool);
 void S9xAPULoadState (uint8 *);
 void S9xAPUSaveState (uint8 *);
 void S9xDumpSPCSnapshot (void);

source/snes9x/memmap.cpp

@@ -3530,6 +3530,7 @@ void CMemory::ApplyROMFixes (void)
 	//// APU timing hacks :(
 
 	Timings.APUSpeedup = 0;
+	Timings.APUAllowTimeOverflow = FALSE;
 
 	if (!Settings.DisableGameSpecificHacks)
 	{
@@ -3571,9 +3572,15 @@ void CMemory::ApplyROMFixes (void)
 			match_na("HEIWA Parlor!Mini8")                      || // Parlor mini 8
 			match_nn("SANKYO Fever! \xCC\xA8\xB0\xCA\xDE\xB0!"))   // SANKYO Fever! Fever!
 			Timings.APUSpeedup = 1;
+
+		if (match_na ("EARTHWORM JIM 2")						|| // Earthworm Jim 2
+			match_na ("NBA Hangtime")							|| // NBA Hang Time
+			match_na ("MSPACMAN"))								   // Ms Pacman
+			Timings.APUAllowTimeOverflow = TRUE;
 	}
 
 	S9xAPUTimingSetSpeedup(Timings.APUSpeedup);
+	S9xAPUAllowTimeOverflow(Timings.APUAllowTimeOverflow);
 
 	//// Other timing hacks :(
 

source/snes9x/snes9x.h

@@ -334,6 +334,7 @@ struct STimings
 	int32	NMIDMADelay;	// The delay of NMI trigger after DMA transfers. Snes9x cannot emulate correctly.
 	int32	IRQPendCount;	// This value is just a hack, because Snes9x cannot emulate any events in an opcode.
 	int32	APUSpeedup;
+	bool8	APUAllowTimeOverflow;
 };
 
 struct SSettings