mmc5 fix

mmc5 fix taken from fceux source code to handle correctly the register
$5130 in fceumm. Now we can play games like Legend of Link nes hack that
need this fix.

src/boards/mmc5.c

@@ -369,7 +369,7 @@ static DECLFW(Mapper5_write) {
 	case 0x5126:
 	case 0x5127:
 		mmc5ABMode = 0;
-		CHRBanksA[A & 7] = V;
+		CHRBanksA[A & 7] = V | ((MMC50x5130 & 0x3) << 8);
 		MMC5CHRA();
 		break;
 	case 0x5128:
@@ -377,9 +377,10 @@ static DECLFW(Mapper5_write) {
 	case 0x512a:
 	case 0x512b:
 		mmc5ABMode = 1;
-		CHRBanksB[A & 3] = V;
+		CHRBanksB[A & 3] = V | ((MMC50x5130 & 0x3) << 8);
 		MMC5CHRB();
 		break;
+	case 0x5130: MMC50x5130 = V; break;		
 	case 0x5200: MMC5HackSPMode = V; break;
 	case 0x5201: MMC5HackSPScroll = (V >> 3) & 0x1F; break;
 	case 0x5202: MMC5HackSPPage = V & 0x3F; break;
@@ -756,6 +757,7 @@ static void GenMMC5_Init(CartInfo *info, int wsize, int battery) {
 	AddExState(&MMC5HackSPMode, 1, 0, "SPLM");
 	AddExState(&MMC5HackSPScroll, 1, 0, "SPLS");
 	AddExState(&MMC5HackSPPage, 1, 0, "SPLP");
+	AddExState(&MMC50x5130, 1, 0, "5130");
 	AddExState(MMC5_StateRegs, ~0, 0, 0);
 
 	MMC5WRAMsize = wsize / 8;

src/fceu.h

@@ -32,6 +32,7 @@ extern int MMC5Hack, PEC586Hack;
 extern uint8 *MMC5HackVROMPTR;
 extern uint8 MMC5HackCHRMode;
 extern uint8 MMC5HackSPMode;
+extern uint8 MMC50x5130;
 extern uint8 MMC5HackSPScroll;
 extern uint8 MMC5HackSPPage;
 

src/ppu.c

@@ -100,6 +100,7 @@ uint8 *MMC5HackExNTARAMPtr = 0;
 uint8 *MMC5HackVROMPTR = 0;
 uint8 MMC5HackCHRMode = 0;
 uint8 MMC5HackSPMode = 0;
+uint8 MMC50x5130 = 0;
 uint8 MMC5HackSPScroll = 0;
 uint8 MMC5HackSPPage = 0;
 

src/pputile.h

@@ -74,6 +74,7 @@ pshift[1] <<= 8;
 	#ifdef PPUT_MMC5CHR1
 		C = MMC5HackVROMPTR;
 		C += (((MMC5HackExNTARAMPtr[RefreshAddr & 0x3ff]) & 0x3f & MMC5HackVROMMask) << 12) + (vadr & 0xfff);
+		C += (MMC50x5130 & 0x3) << 18;
 	#elif defined(PPUT_MMC5)
 		C = MMC5BGVRAMADR(vadr);
 	#else