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put chr-ram back in mmc1

This commit is contained in:
Theron Spiegl 2020-01-19 11:30:51 -06:00
parent 413d9454a4
commit ea70b592ce
2 changed files with 18 additions and 15 deletions
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32
src/cartridge/mmc1.rs
View File

@ -114,21 +114,25 @@ impl Mapper for Mmc1 {
fn read(&mut self, address: usize) -> u8 {
match address {
0x0000..=0x1FFF => {
let offset = address % 0x1000;
if self.chr_bank_mode {
// if 4K bank mode, $0000-$0FFF will be a 4K-indexed section of some CHR-ROM chunk referred to by chr_low_bank
// and $1000-$1FFF will be the one referred to by chr_high_bank
let bank = match address {
0x0000..=0x0FFF => self.chr_low_bank,
0x1000..=0x1FFF => self.chr_high_bank,
_ => panic!("bad address read from MMC1: 0x{:X}", address),
};
let chunk_num = bank / 2;
let chunk_half = if bank % 2 == 0 {0x0} else {0x1000};
self.cart.chr_rom[chunk_num][chunk_half + offset]
if self.cart.chr_rom_size == 0 {
self.chr_ram_bank[address]
} else {
// if we're in 8K bank mode, the whole $0000-$1FFF region will be the 8K range referred to by chr_low_bank
self.cart.chr_rom[self.chr_low_bank][address]
let offset = address % 0x1000;
if self.chr_bank_mode {
// if 4K bank mode, $0000-$0FFF will be a 4K-indexed section of some CHR-ROM chunk referred to by chr_low_bank
// and $1000-$1FFF will be the one referred to by chr_high_bank
let bank = match address {
0x0000..=0x0FFF => self.chr_low_bank,
0x1000..=0x1FFF => self.chr_high_bank,
_ => panic!("bad address read from MMC1: 0x{:X}", address),
};
let chunk_num = bank / 2;
let chunk_half = if bank % 2 == 0 {0x0} else {0x1000};
self.cart.chr_rom[chunk_num][chunk_half + offset]
} else {
// if we're in 8K bank mode, the whole $0000-$1FFF region will be the 8K range referred to by chr_low_bank
self.cart.chr_rom[self.chr_low_bank][address]
}
}
},
0x6000..=0x7FFF => self.prg_ram_bank[address % 0x2000],

1
src/cpu/mod.rs
View File

@ -156,7 +156,6 @@ impl Cpu {
self.apu.trigger_irq = false;
// and mapper MMC3
if self.mapper.borrow_mut().check_irq() && (self.P & INTERRUPT_DISABLE_FLAG == 0) {
// println!("firing IRQ from mapper");
self.irq();
}