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Mapper 242: Use submapper 1 to denote multicart variant that allows write-protecting CHR-RAM in NROM mode. Mappers 227/242: Prevent crashes when accessing PRG-RAM with PRG-RAM being present.

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NewRisingSun
2026-02-04 15:10:35 +01:00
parent ae870894cf
commit febdbaca08
1 changed files with 5 additions and 5 deletions
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10
src/boards/addrlatch.c
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@@ -410,7 +410,7 @@ static void M227Sync(void) {
setmirror(((latche >> 1) & 1) ^ 1);
setchr8(0);
setprg8r(0x10, 0x6000, 0);
if (PRGsize[0x10]) setprg8r(0x10, 0x6000, 0);
}
static DECLFR(M227Read) {
@@ -514,16 +514,15 @@ static void M242Sync(void) {
}
}
}
if (!hasBattery && (latche & 0x80) == 0x80 && (ROM_size * 16) > 256)
/* CHR-RAM write protect hack, needed for some multicarts */
if (latche &0x80 && submapper >0) /* CHR-RAM write protection not used on single-game cartridges (submapper 0) */
SetupCartCHRMapping(0, CHRptr[0], 0x2000, 0);
else
SetupCartCHRMapping(0, CHRptr[0], 0x2000, 1);
setmirror(((latche >> 1) & 1) ^ 1);
setchr8(0);
setprg8r(0x10, 0x6000, 0);
if (PRGsize[0x10]) setprg8r(0x10, 0x6000, 0);
}
static DECLFR(M242Read) {
@@ -542,6 +541,7 @@ static void Mapper242_Reset(void) {
void Mapper242_Init(CartInfo *info) {
dipswitch = 0;
submapper = info->submapper;
M242TwoChips = info->PRGRomSize &0x20000 && info->PRGRomSize >0x20000;
Latch_Init(info, M242Sync, M242Read, 0x0000, 0x8000, 0xFFFF, info->iNES2 && (info->PRGRamSize || info->PRGRamSaveSize) || info->battery);
info->Reset = Mapper242_Reset;