Add differences for TI SN76489 in SG-1000. Fix #100

drhelius · Apr 6, 2024 · 3390eb0 · 3390eb0
1 parent 3639641
commit 3390eb0
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Showing 9 changed files with 45 additions and 19 deletions.
diff --git a/src/Audio.cpp b/src/Audio.cpp
@@ -72,7 +72,7 @@ void Audio::Reset(bool bPAL)
     m_bYM2413Enabled = false;
     m_pYM2413->Enable(false);
     m_bPSGEnabled = true;
-    m_pApu->reset();
+    m_pApu->reset(m_pCartridge->IsSG1000());
     m_pApu->volume(1.0);
     m_pBuffer->clear();
     m_pBuffer->clock_rate(m_bPAL ? GS_MASTER_CLOCK_PAL : GS_MASTER_CLOCK_NTSC);
@@ -144,7 +144,7 @@ void Audio::LoadState(std::istream& stream)
     stream.read(reinterpret_cast<char*> (m_pYM2413Buffer), sizeof(s16) * GS_AUDIO_BUFFER_SIZE);
     m_pYM2413->LoadState(stream);
 
-    m_pApu->reset();
+    m_pApu->reset(m_pCartridge->IsSG1000());
     m_pApu->volume(1.0);
     m_pBuffer->clear();
 }
diff --git a/src/GearsystemCore.cpp b/src/GearsystemCore.cpp
@@ -91,7 +91,7 @@ void GearsystemCore::Init(GS_Color_Format pixelFormat)
     m_pVideo = new Video(m_pMemory, m_pProcessor, m_pCartridge);
     m_pInput = new Input(m_pProcessor);
     m_pAudio = new Audio(m_pCartridge);
-    m_pSmsIOPorts = new SmsIOPorts(m_pAudio, m_pVideo, m_pInput, m_pCartridge, m_pMemory);
+    m_pSmsIOPorts = new SmsIOPorts(m_pAudio, m_pVideo, m_pInput, m_pCartridge, m_pMemory, m_pProcessor);
     m_pGameGearIOPorts = new GameGearIOPorts(m_pAudio, m_pVideo, m_pInput, m_pCartridge, m_pMemory);
 
     m_pMemory->Init();

diff --git a/src/Processor.cpp b/src/Processor.cpp
@@ -35,6 +35,7 @@ Processor::Processor(Memory* pMemory)
     m_bHalt = false;
     m_bBranchTaken = false;
     m_iTStates = 0;
+    m_iInjectedTStates = 0;
     m_bAfterEI = false;
     m_iInterruptMode = 0;
     m_bINTRequested = false;
@@ -84,6 +85,7 @@ void Processor::Reset()
     m_bHalt = false;
     m_bBranchTaken = false;
     m_iTStates = 0;
+    m_iInjectedTStates = 0;
     m_bAfterEI = false;
     m_iInterruptMode = 1;
     PC.SetValue(0x0000);
@@ -121,7 +123,7 @@ IOPorts* Processor::GetIOPOrts()
     return m_pIOPorts;
 }
 
-unsigned int Processor::RunFor(u8 tstates)
+unsigned int Processor::RunFor(unsigned int tstates)
 {
     u8 executed = 0;
 
@@ -168,11 +170,22 @@ unsigned int Processor::RunFor(u8 tstates)
         DisassembleNextOpcode();
 
         executed += m_iTStates;
+
+        if (m_iInjectedTStates > 0)
+        {
+            executed += m_iInjectedTStates;
+            m_iInjectedTStates = 0;
+        }
     }
 
     return executed;
 }
 
+void Processor::InjectTStates(unsigned int tstates)
+{
+    m_iInjectedTStates += tstates;
+}
+
 void Processor::RequestINT(bool assert)
 {
     m_bINTRequested = assert;

diff --git a/src/Processor.h b/src/Processor.h
@@ -59,7 +59,8 @@ class Processor
     ~Processor();
     void Init();
     void Reset();
-    unsigned int RunFor(u8 tstates);
+    unsigned int RunFor(unsigned int tstates);
+    void InjectTStates(unsigned int tstates);
     void RequestINT(bool assert);
     void RequestNMI();
     void SetIOPOrts(IOPorts* pIOPorts);
@@ -101,6 +102,7 @@ class Processor
     bool m_bHalt;
     bool m_bBranchTaken;
     unsigned int m_iTStates;
+    unsigned int m_iInjectedTStates;
     bool m_bAfterEI;
     int m_iInterruptMode;
     IOPorts* m_pIOPorts;

diff --git a/src/SmsIOPorts.cpp b/src/SmsIOPorts.cpp
@@ -19,13 +19,14 @@
 
 #include "SmsIOPorts.h"
 
-SmsIOPorts::SmsIOPorts(Audio* pAudio, Video* pVideo, Input* pInput, Cartridge* pCartridge, Memory* pMemory)
+SmsIOPorts::SmsIOPorts(Audio* pAudio, Video* pVideo, Input* pInput, Cartridge* pCartridge, Memory* pMemory, Processor* pProcessor)
 {
     m_pAudio = pAudio;
     m_pVideo = pVideo;
     m_pInput = pInput;
     m_pCartridge = pCartridge;
     m_pMemory = pMemory;
+    m_pProcessor = pProcessor;
     m_Port3F = 0;
     m_Port3F_HC = 0;
 }

diff --git a/src/SmsIOPorts.h b/src/SmsIOPorts.h
@@ -27,11 +27,12 @@ class Video;
 class Input;
 class Cartridge;
 class Memory;
+class Processor;
 
 class SmsIOPorts : public IOPorts
 {
 public:
-    SmsIOPorts(Audio* pAudio, Video* pVideo, Input* pInput, Cartridge* pCartridge, Memory* pMemory);
+    SmsIOPorts(Audio* pAudio, Video* pVideo, Input* pInput, Cartridge* pCartridge, Memory* pMemory, Processor* pProcessor);
     ~SmsIOPorts();
     void Reset();
     u8 DoInput(u8 port);
@@ -44,6 +45,7 @@ class SmsIOPorts : public IOPorts
     Input* m_pInput;
     Cartridge* m_pCartridge;
     Memory* m_pMemory;
+    Processor* m_pProcessor;
 
     u8 m_Port3F;
     u8 m_Port3F_HC;
@@ -54,6 +56,7 @@ class SmsIOPorts : public IOPorts
 #include "Input.h"
 #include "Cartridge.h"
 #include "Memory.h"
+#include "Processor.h"
 #include "YM2413.h"
 
 inline u8 SmsIOPorts::DoInput(u8 port)
@@ -126,6 +129,8 @@ inline void SmsIOPorts::DoOutput(u8 port, u8 value)
     {
         // Writes to any address go to the SN76489 PSG
         m_pAudio->WriteAudioRegister(value);
+        if (m_pCartridge->IsSG1000())
+            m_pProcessor->InjectTStates(32);
     }
     else if ((port >= 0x80) && (port < 0xC0))
     {

diff --git a/src/audio/Sms_Apu.cpp b/src/audio/Sms_Apu.cpp
@@ -96,8 +96,9 @@ void Sms_Square::run( blip_time_t time, blip_time_t end_time )
 
 static int const noise_periods [3] = { 0x100, 0x200, 0x400 };
 
-inline void Sms_Noise::reset()
+inline void Sms_Noise::reset(bool ti_chip)
 {
+	ti = ti_chip;
 	period = &noise_periods [0];
 	shifter = 0x8000;
 	feedback = 0x9000;
@@ -106,7 +107,12 @@ inline void Sms_Noise::reset()
 
 void Sms_Noise::run( blip_time_t time, blip_time_t end_time )
 {
-	int amp = (shifter & 1) ? 0 : volume * 2;
+	int amp = (shifter & 1) ? 0 : volume;
+
+	if (!ti)
+	{
+		amp *= 2;
+	}
 
 	{
 		int delta = amp - last_amp;
@@ -163,7 +169,7 @@ Sms_Apu::Sms_Apu()
 	oscs [3] = &noise;
 
 	volume( 1.0 );
-	reset();
+	reset(false);
 }
 
 Sms_Apu::~Sms_Apu()
@@ -200,17 +206,15 @@ void Sms_Apu::output( Blip_Buffer* center, Blip_Buffer* left, Blip_Buffer* right
 		osc_output( i, center, left, right );
 }
 
-void Sms_Apu::reset( unsigned feedback, int noise_width )
+void Sms_Apu::reset(bool ti_chip )
 {
 	last_time = 0;
 	latch = 0;
 	ggstereo_save = 0xFF;
 
-	if ( !feedback || !noise_width )
-	{
-		feedback = 0x0009;
-		noise_width = 16;
-	}
+	unsigned feedback = ti_chip ? 0x0003 : 0x0009;
+	int noise_width = ti_chip ? 15 : 16;
+
 	// convert to "Galios configuration"
 	looped_feedback = 1 << (noise_width - 1);
 	noise_feedback  = 0;
@@ -223,7 +227,7 @@ void Sms_Apu::reset( unsigned feedback, int noise_width )
 	squares [0].reset();
 	squares [1].reset();
 	squares [2].reset();
-	noise.reset();
+	noise.reset(ti_chip);
 }
 
 void Sms_Apu::run_until( blip_time_t end_time )

diff --git a/src/audio/Sms_Apu.h b/src/audio/Sms_Apu.h
@@ -30,7 +30,7 @@ class Sms_Apu {
 	void osc_output( int index, Blip_Buffer* center, Blip_Buffer* left, Blip_Buffer* right );
 
 	// Reset oscillators and internal state
-	void reset( unsigned noise_feedback = 0, int noise_width = 0 );
+	void reset( bool ti_chip );
 
 	// Write GameGear left/right assignment byte
 	void write_ggstereo( blip_time_t, int );

diff --git a/src/audio/Sms_Oscs.h b/src/audio/Sms_Oscs.h
@@ -37,11 +37,12 @@ struct Sms_Noise : Sms_Osc
 	const int* period;
 	unsigned shifter;
 	unsigned feedback;
+	bool ti;
 
 	typedef Blip_Synth<blip_med_quality,1> Synth;
 	Synth synth;
 
-	void reset();
+	void reset(bool ti_chip);
 	void run( blip_time_t, blip_time_t );
 };