Merge pull request #1 from libretro/HLE_BIOS

HLE BIOS, activated in case of an invalid BIOS rom file. Tested with commercial games.
libretro · Sep 11, 2013 · 2e814dc · 2e814dc
2 parents cf6338c + 952603f
commit 2e814dc
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Showing 6 changed files with 70 additions and 8 deletions.
diff --git a/libretro/libretro.cpp b/libretro/libretro.cpp
@@ -338,10 +338,7 @@ void lynx_initialize_system(const char* gamepath)
 
     char romfilename[1024];
 
-    if(!lynx_romfilename(romfilename))
-    {
-        return;
-    }
+    lynx_romfilename(romfilename);
 
     lynx = new CSystem(gamepath, romfilename);
 

diff --git a/lynx/Rom.cpp b/lynx/Rom.cpp
@@ -57,7 +57,8 @@ extern CErrorInterface *gError;
 
 CRom::CRom(const char *romfile)
 {
-	mWriteEnable=FALSE;
+	mWriteEnable = FALSE;
+	mValid = FALSE;
 	strncpy(mFileName,romfile,1024);
 	Reset();
 
@@ -71,13 +72,16 @@ CRom::CRom(const char *romfile)
 	if((fp=fopen(mFileName,"rb"))==NULL)
 	{
 		fprintf(stderr, "Invalid ROM.\n");
+		return;
 	}
 
 	// Read in the 512 bytes
 
 	if(fread(mRomData,sizeof(char),ROM_SIZE,fp)!=ROM_SIZE)
 	{
 		fprintf(stderr, "Invalid ROM.\n");
+		fclose(fp);
+		return;
 	}
 
 	fclose(fp);
@@ -100,10 +104,12 @@ CRom::CRom(const char *romfile)
 				gError->Warning("FAKE LYNXBOOT.IMG - CARTRIDGES WILL NOT WORK\n\n"
 								"PLEASE READ THE ACCOMPANYING README.TXT FILE\n\n"
 								"(Do not email the author asking for this image)\n");
-				break;
+				return;
 			}
 		}
 	}
+
+	mValid = TRUE;
 }
 
 void CRom::Reset(void)

diff --git a/lynx/System.cpp b/lynx/System.cpp
@@ -322,6 +322,57 @@ bool CSystem::IsZip(char *filename)
 	return FALSE;
 }
 
+void CSystem::HLE_BIOS_init()
+{
+	fprintf(stderr, "[handy] HLE_BIOS_Init\r\n");
+
+	unsigned char buffer[8];
+
+	int blocksize = (1 + mCart->mMaskBank0) / 256;
+
+	int blockcount = 0x100 - mCart->Peek(0);
+	int start = 1 + blockcount * 51;
+
+	int loadaddr;
+
+	if(blockcount == 1) // cc65
+	{
+		for (int i = 0; i < 0x97; ++i) //2nd loader to 0xFB68
+		{
+			Poke_CPU(0xFB68 + i,  mCart->Peek(start + i));
+		}
+
+		loadaddr = 0xFB68;
+	}
+	else // epyx
+	{
+		blockcount = 0x100 - mCart->Peek(start);
+		start += 1 + blockcount * 51;
+
+		int dir_idx = 1;
+
+		for (int i = 0; i < 8; ++i) //exec directory
+		{
+			buffer[i] = mCart->Peek(start + (dir_idx * 8) + i);
+		}
+
+		int offset = ((int)buffer[0]) * blocksize + (((int)buffer[2]) << 8) + buffer[1];
+
+		loadaddr = (((int)buffer[5]) << 8) + buffer[4];
+		int filesize = (((int)buffer[7]) << 8) + buffer[6];
+
+		for (int i = 0; i < filesize; ++i) 
+		{
+			Poke_CPU(i + loadaddr,  mCart->Peek(offset + i));
+		}	
+	}	
+
+	C6502_REGS regs;
+	mCpu->GetRegs(regs);
+	regs.PC=(UWORD)loadaddr;
+	mCpu->SetRegs(regs);
+}
+
 void CSystem::Reset(void)
 {
 	gSystemCycleCount=0;
@@ -356,6 +407,11 @@ void CSystem::Reset(void)
 	mSusie->Reset();
 	mCpu->Reset();
 
+	if(!mRom->mValid)
+	{
+		HLE_BIOS_init();
+	}
+
 	// Homebrew hashup
 
 	if(mFileType==HANDY_FILETYPE_HOMEBREW)

diff --git a/lynx/cart.h b/lynx/cart.h
@@ -138,11 +138,12 @@ class CCart : public CLynxBase
 		ULONG	mWriteEnableBank0;
 		ULONG	mWriteEnableBank1;
 		ULONG	mCartRAM;
+		ULONG	mMaskBank0;
+		ULONG	mMaskBank1;
 
 	private:
 		EMMODE	mBank;
-		ULONG	mMaskBank0;
-		ULONG	mMaskBank1;
+
 		UBYTE	*mCartBank0;
 		UBYTE	*mCartBank1;
 		char	mName[33];

diff --git a/lynx/rom.h b/lynx/rom.h
@@ -77,6 +77,7 @@ class CRom : public CLynxBase
 
 	public:
 		bool	mWriteEnable;
+		bool	mValid;
 	private:
 		UBYTE	mRomData[ROM_SIZE];
 		char	mFileName[1024];

diff --git a/lynx/system.h b/lynx/system.h
@@ -188,6 +188,7 @@ class CSystem : public CSystemBase
 		~CSystem();
 
 	public:
+		void 	HLE_BIOS_init();
 		void	Reset(void);
 		size_t	MemoryContextSave(const char* tmpfilename, char *context);
 		bool	MemoryContextLoad(const char *context, size_t size);