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Mapper 227: Fix CHR-RAM protect check

This commit is contained in:
negative 2023-04-17 17:53:42 +08:00
parent 8649a38ef9
commit c4ce3ac3fd
1 changed files with 8 additions and 9 deletions
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17
src/boards/addrlatch.cpp
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@ -27,6 +27,7 @@ static void (*WSync)(void);
static readfunc defread;
static uint8 *WRAM = NULL;
static uint32 WRAMSIZE=0;
static uint8 hasBattery = 0;
static DECLFW(LatchWrite) {
latche = A;
@ -358,20 +359,17 @@ void Mapper217_Init(CartInfo *info) {
}
//------------------ Map 227 ---------------------------
static void M227Sync(void) {
uint32 S = latche & 1;
uint32 p = ((latche >> 2) & 0x1F) + ((latche & 0x100) >> 3);
uint32 L = (latche >> 9) & 1;
// ok, according to nesdev wiki (refrenced to the nesdev dumping thread) there is a CHR write protection bit7.
// however, this bit clearly determined a specific PRG layout for some game but does not meant to have additional
// functionality. as I see from the menu code, it disables the chr writing before run an actual game.
// this fix here makes happy both waixing rpgs and multigame menus at once. can't veryfy it on a hardware
// but if I find some i'll definitly do this.
if ((latche & 0xF000) == 0xF000)
SetupCartCHRMapping(0, CHRptr[0], 0x2000, 0);
// Only Waixing appear to have battery flag enabled, while multicarts don't.
// Multicarts needs CHR-RAM protect in NROM modes, so only apply CHR-RAM protect
// on non battery-enabled carts.
if (!hasBattery && (latche & 0x80) == 0x80)
/* CHR-RAM write protect hack, needed for some multicarts */
SetupCartCHRMapping(0, CHRptr[0], 0x2000, 0);
else
SetupCartCHRMapping(0, CHRptr[0], 0x2000, 1);
@ -409,6 +407,7 @@ static void M227Sync(void) {
void Mapper227_Init(CartInfo *info) {
Latch_Init(info, M227Sync, NULL, 0x0000, 0x8000, 0xFFFF, 1);
hasBattery = info->battery;
}
//------------------ Map 229 ---------------------------