diff --git a/BizHawk.Emulation.Cores/BizHawk.Emulation.Cores.csproj b/BizHawk.Emulation.Cores/BizHawk.Emulation.Cores.csproj
index f2fe0b8ea3..9feb51d1c5 100644
--- a/BizHawk.Emulation.Cores/BizHawk.Emulation.Cores.csproj
+++ b/BizHawk.Emulation.Cores/BizHawk.Emulation.Cores.csproj
@@ -638,6 +638,7 @@
+
Code
diff --git a/BizHawk.Emulation.Cores/Consoles/Nintendo/NES/Boards/UNIF/UNIF_BMC-A65AS.cs b/BizHawk.Emulation.Cores/Consoles/Nintendo/NES/Boards/UNIF/UNIF_BMC-A65AS.cs
new file mode 100644
index 0000000000..f6423166f4
--- /dev/null
+++ b/BizHawk.Emulation.Cores/Consoles/Nintendo/NES/Boards/UNIF/UNIF_BMC-A65AS.cs
@@ -0,0 +1,83 @@
+using BizHawk.Common;
+using BizHawk.Common.NumberExtensions;
+
+namespace BizHawk.Emulation.Cores.Nintendo.NES
+{
+ public class UNIF_BMC_A65AS : NES.NESBoardBase
+ {
+ private int _prgReg;
+ private bool _isPrg32kMode;
+
+ private int prgMask16k;
+ private int prgMask32k;
+
+ public override bool Configure(NES.EDetectionOrigin origin)
+ {
+ switch (Cart.board_type)
+ {
+ case "UNIF_BMC-A65AS":
+ break;
+ default:
+ return false;
+ }
+
+ prgMask16k = Cart.prg_size / 16 - 1;
+ prgMask32k = Cart.prg_size / 32 - 1;
+
+ return true;
+ }
+
+ public override void SyncState(Serializer ser)
+ {
+ base.SyncState(ser);
+ ser.Sync("prgReg", ref _prgReg);
+ ser.Sync("isPrg32kMode", ref _isPrg32kMode);
+ }
+
+ public override void WritePRG(int addr, byte value)
+ {
+ _isPrg32kMode = value.Bit(6);
+ _prgReg = value;
+
+ // From FCEUX:
+ // actually, there is two cart in one... First have extra mirroring
+ // mode (one screen) and 32K bankswitching, second one have only
+ // 16 bankswitching mode and normal mirroring... But there is no any
+ // correlations between modes and they can be used in one mapper code.
+ if (value.Bit(7))
+ {
+ SetMirrorType(value.Bit(5) ? EMirrorType.OneScreenB : EMirrorType.OneScreenA);
+ }
+ else
+ {
+ SetMirrorType(value.Bit(3) ? EMirrorType.Horizontal : EMirrorType.Vertical);
+ }
+ }
+
+ public override byte ReadPRG(int addr)
+ {
+ if (_isPrg32kMode)
+ {
+ int bank = (_prgReg >> 1) & 0xF;
+ bank &= prgMask32k;
+ return ROM[(bank * 0x8000) + (addr & 0x7FFF)];
+ }
+ else
+ {
+
+ if (addr < 0x4000)
+ {
+ int bank = (_prgReg & 0x30) >> 1 | _prgReg & 7;
+ bank &= prgMask16k;
+ return ROM[(bank * 0x4000) + (addr & 0x3FFF)];
+ }
+ else
+ {
+ int bank = (_prgReg & 0x30) >> 1 | 7;
+ bank &= prgMask16k;
+ return ROM[(bank * 0x4000) + (addr & 0x3FFF)];
+ }
+ }
+ }
+ }
+}