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Slightly improve MBC3 accuracy

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This commit is contained in:
Lior Halphon 2021-02-26 00:52:18 +02:00
parent 71c6fa45e0
commit 72cb391612
1 changed files with 21 additions and 10 deletions
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31
Core/memory.c
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@ -190,13 +190,16 @@ static uint8_t read_mbc_ram(GB_gameboy_t *gb, uint16_t addr)
} }
if (gb->cartridge_type->has_rtc && gb->cartridge_type->mbc_type != GB_HUC3 && if (gb->cartridge_type->has_rtc && gb->cartridge_type->mbc_type != GB_HUC3 &&
gb->mbc3_rtc_mapped && gb->mbc_ram_bank <= 4) { gb->mbc3_rtc_mapped) {
/* RTC read */ /* RTC read */
gb->rtc_latched.seconds &= 0x3F; if (gb->mbc_ram_bank <= 4) {
gb->rtc_latched.minutes &= 0x3F; gb->rtc_latched.seconds &= 0x3F;
gb->rtc_latched.hours &= 0x1F; gb->rtc_latched.minutes &= 0x3F;
gb->rtc_latched.high &= 0xC1; gb->rtc_latched.hours &= 0x1F;
return gb->rtc_latched.data[gb->mbc_ram_bank]; gb->rtc_latched.high &= 0xC1;
return gb->rtc_latched.data[gb->mbc_ram_bank];
}
return 0xFF;
} }
if (gb->camera_registers_mapped) { if (gb->camera_registers_mapped) {
@ -213,6 +216,9 @@ static uint8_t read_mbc_ram(GB_gameboy_t *gb, uint16_t addr)
uint8_t effective_bank = gb->mbc_ram_bank; uint8_t effective_bank = gb->mbc_ram_bank;
if (gb->cartridge_type->mbc_type == GB_MBC3 && !gb->is_mbc30) { if (gb->cartridge_type->mbc_type == GB_MBC3 && !gb->is_mbc30) {
if (gb->cartridge_type->has_rtc) {
if (effective_bank > 3) return 0xFF;
}
effective_bank &= 0x3; effective_bank &= 0x3;
} }
uint8_t ret = gb->mbc_ram[((addr & 0x1FFF) + effective_bank * 0x2000) & (gb->mbc_ram_size - 1)]; uint8_t ret = gb->mbc_ram[((addr & 0x1FFF) + effective_bank * 0x2000) & (gb->mbc_ram_size - 1)];
@ -695,11 +701,13 @@ static void write_mbc_ram(GB_gameboy_t *gb, uint16_t addr, uint8_t value)
return; return;
} }
if (gb->cartridge_type->has_rtc && gb->mbc3_rtc_mapped && gb->mbc_ram_bank <= 4) { if (gb->cartridge_type->has_rtc && gb->mbc3_rtc_mapped) {
if (gb->mbc_ram_bank == 0) { if (gb->mbc_ram_bank <= 4) {
gb->rtc_cycles = 0; if (gb->mbc_ram_bank == 0) {
gb->rtc_cycles = 0;
}
gb->rtc_latched.data[gb->mbc_ram_bank] = gb->rtc_real.data[gb->mbc_ram_bank] = value;
} }
gb->rtc_latched.data[gb->mbc_ram_bank] = gb->rtc_real.data[gb->mbc_ram_bank] = value;
return; return;
} }
@ -709,6 +717,9 @@ static void write_mbc_ram(GB_gameboy_t *gb, uint16_t addr, uint8_t value)
uint8_t effective_bank = gb->mbc_ram_bank; uint8_t effective_bank = gb->mbc_ram_bank;
if (gb->cartridge_type->mbc_type == GB_MBC3 && !gb->is_mbc30) { if (gb->cartridge_type->mbc_type == GB_MBC3 && !gb->is_mbc30) {
if (gb->cartridge_type->has_rtc) {
if (effective_bank > 3) return;
}
effective_bank &= 0x3; effective_bank &= 0x3;
} }