Randomize PI and SI DMA timing

This should help with randomization while FAT is on.

Source/Project64-core/3rdParty/Random.cpp

@@ -0,0 +1,48 @@
+/****************************************************************************
+*                                                                           *
+* Project64 - A Nintendo 64 emulator.                                      *
+* http://www.pj64-emu.com/                                                  *
+* Copyright (C) 2017 Project64. All rights reserved.                        *
+*                                                                           *
+* License:                                                                  *
+* GNU/GPLv2 http://www.gnu.org/licenses/gpl-2.0.html                        *
+*                                                                           *
+****************************************************************************/
+/*
+ * Implements the CRandom class.
+ *
+ * This class implements the Lehmer Random Number Generator.
+ * 
+ */
+
+#include "Random.h"
+#include <time.h>
+
+CRandom::CRandom()
+{
+    state = (uint32_t)time(NULL);
+}
+
+CRandom::CRandom(uint32_t seed_value)
+{
+    state = seed_value;
+}
+
+uint32_t randomizer(uint32_t val)
+{
+    return ((uint64_t)val * 279470273UL) % 4294967291UL;
+}
+
+uint32_t CRandom::next()
+{
+    state = randomizer(state);
+    return state;
+}
+
+void CRandom::seed(uint32_t seed_value)
+{
+    if (seed_value == 0)
+        state == 1;
+    else
+        state = seed_value;
+}

Source/Project64-core/3rdParty/Random.h

@@ -0,0 +1,31 @@
+/****************************************************************************
+*                                                                           *
+* Project64 - A Nintendo 64 emulator.                                      *
+* http://www.pj64-emu.com/                                                  *
+* Copyright (C) 2017 Project64. All rights reserved.                        *
+*                                                                           *
+* License:                                                                  *
+* GNU/GPLv2 http://www.gnu.org/licenses/gpl-2.0.html                        *
+*                                                                           *
+****************************************************************************/
+/*
+ * Defines the CRandom class.
+ *
+ * This class implements the Lehmer Random Number Generator.
+ *
+ */
+
+#include <Common/stdtypes.h>
+
+class CRandom
+{
+public:
+    CRandom();
+    CRandom(uint32_t seed_value);
+    uint32_t next();
+    void seed(uint32_t seed_value);
+
+protected:
+    uint32_t randomizer(uint32_t val);
+    uint32_t state;
+};

Source/Project64-core/N64System/Mips/Dma.cpp

@@ -458,9 +458,11 @@ void CDMA::PI_DMA_WRITE()
         {
             g_Recompiler->ClearRecompCode_Phys(g_Reg->PI_DRAM_ADDR_REG, g_Reg->PI_WR_LEN_REG, CRecompiler::Remove_DMA);
         }
-        g_Reg->PI_STATUS_REG &= ~PI_STATUS_DMA_BUSY;
+        g_SystemTimer->SetTimer(g_SystemTimer->PiTimer, PI_WR_LEN_REG/8 + (g_Random->next() % 0x40), false);
-        g_Reg->MI_INTR_REG |= MI_INTR_PI;
+
-        g_Reg->CheckInterrupts();
+        //g_Reg->PI_STATUS_REG &= ~PI_STATUS_DMA_BUSY;
+        //g_Reg->MI_INTR_REG |= MI_INTR_PI;
+        //g_Reg->CheckInterrupts();
         //ChangeTimer(PiTimer,(int32_t)(PI_WR_LEN_REG * 8.9) + 50);
         //ChangeTimer(PiTimer,(int32_t)(PI_WR_LEN_REG * 8.9));
         return;

Source/Project64-core/N64System/Mips/PifRam.cpp

@@ -358,13 +358,14 @@ void CPifRam::SI_DMA_READ()
 
     if (g_System->bDelaySI())
     {
-        g_SystemTimer->SetTimer(CSystemTimer::SiTimer, 0x900, false);
+        g_SystemTimer->SetTimer(CSystemTimer::SiTimer, 0x900 + (g_Random->next() % 0x40), false);
     }
     else
     {
-        g_Reg->MI_INTR_REG |= MI_INTR_SI;
+        g_SystemTimer->SetTimer(CSystemTimer::SiTimer, g_Random->next() % 0x40, false);
-        g_Reg->SI_STATUS_REG |= SI_STATUS_INTERRUPT;
+        //g_Reg->MI_INTR_REG |= MI_INTR_SI;
-        g_Reg->CheckInterrupts();
+        //g_Reg->SI_STATUS_REG |= SI_STATUS_INTERRUPT;
+        //g_Reg->CheckInterrupts();
     }
 }
 

Source/Project64-core/N64System/N64Class.cpp

@@ -716,6 +716,7 @@ void CN64System::Reset(bool bInitReg, bool ClearMenory)
         m_SyncCPU->Reset(bInitReg, ClearMenory);
     }
     g_Settings->SaveBool(GameRunning_InReset, true);
+
     WriteTrace(TraceN64System, TraceDebug, "Done");
 }
 
@@ -763,6 +764,7 @@ bool CN64System::SetActiveSystem(bool bActive)
         R4300iOp::m_TestTimer = m_TestTimer;
         R4300iOp::m_NextInstruction = m_NextInstruction;
         R4300iOp::m_JumpToLocation = m_JumpToLocation;
+        g_Random = &m_Random;
     }
     else
     {
@@ -782,6 +784,7 @@ bool CN64System::SetActiveSystem(bool bActive)
             g_Plugins = m_Plugins;
             g_TLBLoadAddress = NULL;
             g_TLBStoreAddress = NULL;
+            g_Random = NULL;
         }
     }
 

Source/Project64-core/N64System/N64Class.h

@@ -23,6 +23,7 @@
 #include <Project64-core/Settings/DebugSettings.h>
 #include <Project64-core/Plugin.h>
 #include <Project64-core/Logging.h>
+#include <Project64-core/3rdParty/Random.h>
 
 #include "Mips/TLBClass.h"
 #include "CheatClass.h"
@@ -164,6 +165,7 @@ private:
     uint32_t        m_SyncCount;
     bool            m_SyncCpu;
     bool            m_CheatsSlectionChanged;
+    CRandom         m_Random;
 
     //When Syncing cores this is the PC where it last Sync'ed correctly
     uint32_t m_LastSuccessSyncPC[10];

Source/Project64-core/N64System/SystemGlobals.h

@@ -62,4 +62,7 @@ extern CDebugger     * g_Debugger;
 extern uint8_t      ** g_RecompPos;
 
 class CMempak;
-extern CMempak       * g_Mempak;
+extern CMempak       * g_Mempak;
+
+class CRandom;
+extern CRandom       * g_Random;

Source/Project64-core/Project64-core.vcxproj

@@ -35,6 +35,7 @@
     <ClCompile Include="3rdParty\7zip.cpp">
       <PrecompiledHeader>NotUsing</PrecompiledHeader>
     </ClCompile>
+    <ClCompile Include="3rdParty\Random.cpp" />
     <ClCompile Include="AppInit.cpp" />
     <ClCompile Include="Logging.cpp" />
     <ClCompile Include="MemoryExceptionFilter.cpp" />
@@ -126,6 +127,7 @@
     <ClInclude Include="..\3rdParty\zlib\zconf.h" />
     <ClInclude Include="..\3rdParty\zlib\zlib.h" />
     <ClInclude Include="3rdParty\7zip.h" />
+    <ClInclude Include="3rdParty\Random.h" />
     <ClInclude Include="3rdParty\zip.h" />
     <ClInclude Include="AppInit.h" />
     <ClInclude Include="Debugger.h" />

Source/Project64-core/Project64-core.vcxproj.filters

@@ -339,6 +339,9 @@
     <ClCompile Include="N64System\Recompiler\Arm\ArmRegInfo.cpp">
       <Filter>Source Files\N64 System\Recompiler\Arm</Filter>
     </ClCompile>
+    <ClCompile Include="3rdParty\Random.cpp">
+      <Filter>Source Files\3rd Party</Filter>
+    </ClCompile>
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="stdafx.h">
@@ -659,6 +662,9 @@
     <ClInclude Include="Debugger.h">
       <Filter>Header Files</Filter>
     </ClInclude>
+    <ClInclude Include="3rdParty\Random.h">
+      <Filter>Header Files\3rd Party</Filter>
+    </ClInclude>
   </ItemGroup>
   <ItemGroup>
     <None Include="ClassDiagram.cd" />