Merge pull request #155 from dshadoff/PCE_fix_HuCard_BRAM_protection

Default behaviour for BRAM should be 'locked' at startup; this is currently correct for CDROM games, but not for HuCard games. This means that memory at physical address $1EE000 should be all $FF values (as seen by the Physical Memory debug screen), but the BRAM memory editor screen should show the BRAM properly.
pce-devel · Apr 13, 2024 · 3a78525 · 3a78525
2 parents 7edc9b2 + 4edf275
commit 3a78525
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Showing 5 changed files with 21 additions and 18 deletions.
diff --git a/mednafen/src/pce/huc.cpp b/mednafen/src/pce/huc.cpp
@@ -134,7 +134,7 @@ static DECLFR(SaveRAMRead)
  if(BRAM_Disabled)
   return(0xFF);
 
- if((!PCE_IsCD || PCECD_IsBRAMEnabled()) && (A & 8191) < 2048)
+ if((PCE_IsBRAMEnabled()) && (A & 8191) < 2048)
   return(SaveRAM[A & 2047]);
  else
   return(0xFF);
@@ -145,7 +145,7 @@ static DECLFW(SaveRAMWrite)
  if(BRAM_Disabled)
   return;
 
- if((!PCE_IsCD || PCECD_IsBRAMEnabled()) && (A & 8191) < 2048)
+ if((PCE_IsBRAMEnabled()) && (A & 8191) < 2048)
   SaveRAM[A & 2047] = V;
 }
 

diff --git a/mednafen/src/pce/pce.cpp b/mednafen/src/pce/pce.cpp
@@ -67,6 +67,7 @@ static bool SetSoundRate(double rate);
 static void Cleanup(void);
 
 bool PCE_ACEnabled;
+bool bBRAMEnabled;
 uint32 PCE_InDebug = 0;
 uint64 PCE_TimestampBase;	// Only used with the debugger for the time being.
 
@@ -174,6 +175,9 @@ static DECLFR(IORead)
   case 0x1800: if(IsTsushin)
 		return(PCE_TsushinRead(A));
 
+               if (((A & 0x1fff) == 0x1803) && (!PCE_InDebug))
+                 bBRAMEnabled = false;
+
 	       if(!PCE_IsCD)
 		break;
 	       if((A & 0x1E00) == 0x1A00)
@@ -240,6 +244,9 @@ static DECLFW(IOWrite)
   case 0x1800: if(IsTsushin)
                 PCE_TsushinWrite(A & 0x1FFF, V);
 
+	       if ((A & 0x1fff) == 0x1807)       // $1807: D7=1 enables backup ram
+                bBRAMEnabled = (V & 0x80) ? true : false;
+
 	       if(!PCE_IsCD)
 	       {
 		if(!PCE_InDebug)
@@ -1004,6 +1011,7 @@ static void StateAction(StateMem *sm, const unsigned load, const bool data_only)
  {
   SFPTR8(BaseRAM, IsSGX? 32768 : 8192),
   SFVAR(PCE_TimestampBase),
+  SFVAR(bBRAMEnabled),
 
   SFEND
  };
@@ -1048,6 +1056,8 @@ void PCE_Power(void)
 
  PCEINPUT_Power(timestamp);
 
+ bBRAMEnabled = false;
+
  if(PCE_IsCD)
  {
   vce->SetCDEvent(PCECD_Power(timestamp));
@@ -1071,6 +1081,11 @@ static void SetMedia(uint32 drive_idx, uint32 state_idx, uint32 media_idx, uint3
  }
 }
 
+bool PCE_IsBRAMEnabled()
+{
+ return bBRAMEnabled;
+}
+
 static void DoSimpleCommand(int cmd)
 {
  switch(cmd)

diff --git a/mednafen/src/pce/pce.h b/mednafen/src/pce/pce.h
@@ -27,6 +27,8 @@ MDFN_HIDE extern uint32 PCE_InDebug;
 MDFN_HIDE extern bool PCE_ACEnabled; // Arcade Card emulation enabled?
 void PCE_Power(void);
 
+bool PCE_IsBRAMEnabled(void);
+
 uint8 PCE_PeekMainRAM(uint32 A);
 void PCE_PokeMainRAM(uint32 A, uint8 V);
 

diff --git a/mednafen/src/pce/pcecd.cpp b/mednafen/src/pce/pcecd.cpp
@@ -106,7 +106,6 @@ static bool ADPCMExtraPrecision;
 //static bool ADPCMFancyLP;	// Commented out, not really a worthwhile feature IMO(sound effects don't sound right without the extra spectrum duplicates).
 
 
-static bool	bBRAMEnabled;
 static uint8	_Port[15];
 static uint8 	ACKStatus;
 
@@ -490,7 +489,6 @@ int32 PCECD_Power(uint32 timestamp)
 	SCSICD_Power(timestamp);
         scsicd_ne = 0x7fffffff;
 
-        bBRAMEnabled = false;
         memset(_Port, 0, sizeof(_Port));
 	ACKStatus = 0;
 	ClearACKDelay = 0;
@@ -530,11 +528,6 @@ int32 PCECD_Power(uint32 timestamp)
 	return(CalcNextEvent(0x7FFFFFFF));
 }
 
-bool PCECD_IsBRAMEnabled()
-{
-	return bBRAMEnabled;
-}
-
 MDFN_FASTCALL uint8 PCECD_Read(uint32 timestamp, uint32 A, int32 &next_event, const bool PeekMode)
 {
  uint8 ret = 0;
@@ -573,9 +566,7 @@ MDFN_FASTCALL uint8 PCECD_Read(uint32 timestamp, uint32 A, int32 &next_event, co
    case 0x2: ret = _Port[2];
 	     break;
 
-   case 0x3: if(!PeekMode)
-               bBRAMEnabled = false;
-
+   case 0x3:
 	     /* switch left/right of digitized cd playback */
 	     ret = _Port[0x3];
 	     if(!PeekMode)
@@ -760,9 +751,7 @@ MDFN_FASTCALL int32 PCECD_Write(uint32 timestamp, uint32 physAddr, uint8 data)
 			 }
 			 break;
 
-		case 0x7:	// $1807: D7=1 enables backup ram 
-
-			bBRAMEnabled = (data & 0x80) ? true : false;
+		case 0x7:
 			break;
 
 		case 0x8:	// Set ADPCM address low
@@ -1374,7 +1363,6 @@ void PCECD_StateAction(StateMem *sm, const unsigned load, const bool data_only)
 {
 	SFORMAT StateRegs[] =
 	{
-	 SFVAR(bBRAMEnabled),
 	 SFVAR(ACKStatus),
 	 SFVAR(ClearACKDelay),
 	 SFVAR(RawPCMVolumeCache),

diff --git a/mednafen/src/pce/pcecd.h b/mednafen/src/pce/pcecd.h
@@ -52,8 +52,6 @@ int32 PCECD_Power(uint32 timestamp);
 MDFN_FASTCALL uint8 PCECD_Read(uint32 timestamp, uint32, int32 &next_event, const bool PeekMode = false);
 MDFN_FASTCALL int32 PCECD_Write(uint32 timestamp, uint32, uint8 data) MDFN_WARN_UNUSED_RESULT;
 
-bool PCECD_IsBRAMEnabled();
-
 void PCECD_StateAction(StateMem *sm, const unsigned load, const bool data_only);
 
 void ADPCM_PeekRAM(uint32 Address, uint32 Length, uint8 *Buffer);