NES - start mapper 96 (prg mapping working)

BizHawk.Emulation/BizHawk.Emulation.csproj

@@ -124,6 +124,7 @@
       <SubType>Code</SubType>
     </Compile>
     <Compile Include="Consoles\Nintendo\NES\Boards\BANDAI-FCG-1.cs" />
+    <Compile Include="Consoles\Nintendo\NES\Boards\BANDAI_74_161_02_74.cs" />
     <Compile Include="Consoles\Nintendo\NES\Boards\BANDAI_74_161_161_32.cs" />
     <Compile Include="Consoles\Nintendo\NES\Boards\BxROM.cs" />
     <Compile Include="Consoles\Nintendo\NES\Boards\Camerica.cs" />

BizHawk.Emulation/Consoles/Nintendo/NES/Boards/BANDAI_74_161_02_74.cs

@@ -0,0 +1,157 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace BizHawk.Emulation.Consoles.Nintendo
+{
+	class BANDAI_74_161_02_74 : NES.NESBoardBase
+	{
+		/*
+		Here are Disch's original notes:  
+		========================
+		=  Mapper 096          =
+		========================
+
+
+		Example Games:
+		--------------------------
+		Oeka Kids - Anpanman no Hiragana Daisuki
+		Oeka Kids - Anpanman to Oekaki Shiyou!!
+
+
+		Notes:
+		---------------------------
+		These games use the Oeka Kids tablet -- so you'll need to add support for that if you really want to test
+		these.
+
+		These games use 32k of CHR-RAM, which is swappable in a very unique fashion.  Be sure to read the CHR Setup
+		section in detail.
+
+
+		Registers:
+		---------------------------
+		I'm unsure whether or not this mapper suffers from bus conflicts.  Use caution!
+
+
+		  $8000-FFFF:  [.... .CPP]
+			C = CHR Block select (see CHR Setup)
+			P = PRG Page select (32k @ $8000)
+
+
+
+		CHR Setup:
+		---------------------------
+
+		This mapper is tricky!!!
+
+		Firstly, this mapper divides the 32k CHR-RAM into two 16k blocks (above 'C' bit selects which block is used).
+		The selected pages (including the fixed page) are taken from only the currently selected 16k block.
+
+			  $0000   $0400   $0800   $0C00   $1000   $1400   $1800   $1C00 
+			+-------------------------------+-------------------------------+
+			|         **See below**         |             { 3 }             |
+			+-------------------------------+-------------------------------+
+
+
+		But that's the easy part.  This mapper does a very, very cool trick which watches the PPU address lines to
+		effectively "split" the nametable into 4 smaller sections -- thereby assigning a different CHR-RAM page to
+		each section.  This allows **every single tile in the NT** to have a unique tile graphic!
+
+		Long story short:
+
+		A nametable spans from $2000-$23BF   ($23C0-$23FF are the attribute table).
+		The mapper breaks the NT up like so:
+
+		$2000-20FF = use CHR page 0
+		$2100-21FF = use CHR page 1
+		$2200-22FF = use CHR page 2
+		$2300-23BF = use CHR page 3
+
+		the other nametables at $2400, $2800, $2C00 are broken up in the same fashion.
+
+
+
+
+		Long story long:
+
+		PPU Address lines are modified as the PPU fetches tiles, and also when the game manually changes the PPU
+		address (via the second write to $2006 --- or by the increment after read/writing $2007).  The mapper
+		monitors every change to the PPU Address lines, and when it lies within a certain range, it swaps the
+		appropriate CHR page in.
+
+		It will only swap CHR when the address falls between $2000-2FFF (or mirrored regions like $6000-6FFF,
+		$A000-AFFF, $E000-EFFF).  $3xxx will not trigger a swap.
+
+		When in that range, it checks to make sure the address is not attribute tables ((Addr AND $03FF) < $03C0).
+		Note I'm not 100% sure if the mapper really does this or not.  It's very possible that attribute fetches will
+		also swap CHR... this would not really disrupt anything other than making the game be more careful about its
+		PPU writes.
+
+		When all that checks out, bits 8 and 9 (Addr AND $0300) select the 4k CHR page to swap in to $0000.
+
+
+		Note that the mapper does not distinguish between PPU driven line changes and game driven line changes.
+		This means that games can manually swap the CHR page by doing specific writes to $2006:
+
+
+		LDA #$20
+		STA $2006
+		STA $2006   ; Addr set to $20xx -- CHR page 0 selected
+ 
+		LDA #$21
+		STA $2006
+		STA $2006   ; Addr set to $21xx -- CHR page 1 selected
+ 
+		And in fact, games would HAVE to do that to select CHR, since that's the only way to fill CHR RAM with the
+		desired data.  So make sure your emu supports this.
+		*/
+		int chr_block;
+		int prg_bank_mask_32k;
+		byte prg_bank_32k;
+
+		public override bool Configure(NES.EDetectionOrigin origin)
+		{
+			//analyze board type
+			switch (Cart.board_type)
+			{
+				case "MAPPER096":
+					break;
+				default:
+					return false;
+			}
+
+			chr_block = 0;
+			prg_bank_mask_32k = Cart.prg_size / 32 - 1;
+			return true;
+		}
+
+		public override void SyncState(Serializer ser)
+		{
+			base.SyncState(ser);
+			ser.Sync("chr_block", ref chr_block);
+			ser.Sync("prg_bank_mask_16k", ref prg_bank_mask_32k);
+			ser.Sync("prg_bank_16k", ref prg_bank_32k);
+		}
+
+		public override void WritePRG(int addr, byte value)
+		{
+			prg_bank_mask_32k = (byte)(value & 0x03);
+			chr_block = (value >> 2) & 0x01;
+		}
+
+		public override byte ReadPRG(int addr)
+		{
+			int bank_32k = prg_bank_32k & prg_bank_mask_32k;
+			return ROM[(bank_32k * 0x8000) + addr];
+		}
+
+		public override byte ReadPPU(int addr)
+		{
+			if (addr < 0x2000)
+			{
+			}
+			return base.ReadPPU(addr);
+		}
+	}
+}