Files
nes-emu/src/mem.rs

782 lines
25 KiB
Rust

use std::{fmt, sync::Arc};
use bitfield::bitfield;
use crate::{
CPUMMRegisters, PPU, apu::APU, controllers::Controllers, cpu::DmaState, ppu::PPUMMRegisters,
};
pub trait Memory {
fn peek(&self, val: usize) -> Option<u8>;
fn len(&self) -> usize;
fn edit_ver(&self) -> usize;
}
#[derive(Debug, Clone)]
pub enum Value<R> {
Value(u8),
Register { reg: R, offset: u16 },
}
impl<R> Value<R> {
pub fn reg_map(self, f: impl FnOnce(R, u16) -> u8) -> u8 {
match self {
Value::Value(v) => v,
Value::Register { reg, offset } => f(reg, offset),
}
}
}
#[derive(Debug, Clone)]
pub enum Data<R> {
RAM(Vec<u8>),
ROM(Arc<[u8]>),
Mirror(u16),
Reg(R),
// Disabled,
}
#[derive(Debug, Clone)]
pub struct Segment<R> {
name: SegmentId,
position: u16,
size: u16,
mem: Data<R>,
}
impl<R> Segment<R> {
fn is(&self, id: SegmentId) -> bool {
self.name == id
}
fn ram(name: SegmentId, position: u16, size: u16) -> Self {
Self {
name,
position,
size,
mem: Data::RAM(vec![0u8; size as usize]),
}
}
fn rom<Raw>(name: SegmentId, position: u16, raw: Raw) -> Self
where
Arc<[u8]>: From<Raw>,
{
let raw = Arc::from(raw);
Self {
name,
position,
size: raw.len() as u16,
mem: Data::ROM(raw),
}
}
fn reg(name: SegmentId, position: u16, size: u16, reg: R) -> Self {
Self {
name,
position,
size,
mem: Data::Reg(reg),
}
}
fn mirror(name: SegmentId, position: u16, size: u16, of: u16) -> Self {
Self {
name,
position,
size,
mem: Data::Mirror(of),
}
}
// fn take_rom(&mut self) -> Vec<u8> {
// match std::mem::replace(&mut self.mem, Data::Disabled) {
// Data::ROM(items) => items,
// _ => panic!("Cannot take rom since memory is not rom"),
// }
// }
// fn set_rom(&mut self, rom: Vec<u8>) {
// assert!(
// matches!(self.mem, Data::Disabled),
// "Cannot set non-disabled memory to rom"
// );
// self.mem = Data::ROM(rom);
// }
fn swap_rom(&mut self, rom: Arc<[u8]>) {
match &mut self.mem {
Data::ROM(items) => *items = rom,
_ => panic!("Cannot swap rom since memory is not rom"),
}
}
pub fn power_cycle(&mut self) {
match &mut self.mem {
Data::RAM(v) => v.fill(0),
_ => (),
}
}
}
#[derive(Debug, Clone)]
pub struct MemoryMap<R> {
edit_ver: usize,
segments: Vec<Segment<R>>,
// map: Remapper,
}
impl<R: Copy> MemoryMap<R> {
pub fn read(&self, addr: u16) -> Value<R> {
// self.edit_ver += 1;
for segment in &self.segments {
if segment.position <= addr && addr - segment.position < segment.size {
return match &segment.mem {
Data::RAM(items) => Value::Value(items[(addr - segment.position) as usize]),
Data::ROM(items) => Value::Value(items[(addr - segment.position) as usize]),
Data::Reg(reg) => Value::Register {
reg: *reg,
offset: addr - segment.position,
},
Data::Mirror(pos) => {
let offset = addr - segment.position;
self.read(pos + offset)
// let s = &self.segments[*index];
// self.read(s.position + offset % s.size)
} // Data::Disabled => todo!(),
};
}
}
// TODO: Open bus
Value::Value(0)
// todo!("Open bus")
}
pub fn write(&mut self, addr: u16, val: u8) -> Option<(R, u16, u8)> {
self.edit_ver += 1;
for segment in &mut self.segments {
if segment.position <= addr && addr - segment.position < segment.size {
return match &mut segment.mem {
Data::RAM(items) => {
items[(addr - segment.position) as usize] = val;
None
}
Data::ROM(_items) => None,
Data::Reg(reg) => Some((*reg, addr - segment.position, val)),
Data::Mirror(pos) => {
let pos = *pos;
let offset = addr - segment.position;
self.write(pos + offset, val)
// let index = *index;
// let s = &self.segments[index];
// self.write(s.position + offset % s.size, val)
} // Data::Disabled => todo!(),
};
}
}
// iirc, open bus just drops writes
None
// todo!("Open bus (${addr:04X})")
}
// pub fn clear(&mut self) {
// for s in &mut self.segments {
// match &mut s.mem {
// Data::RAM(items) => items.fill(0),
// _ => (),
// }
// }
// }
pub fn power_cycle(&mut self) -> Self {
for seg in &mut self.segments {
seg.power_cycle();
}
let segments = std::mem::take(&mut self.segments);
Self {
edit_ver: self.edit_ver + 1,
segments,
// map: self.map.power_cycle(),
}
}
fn find(&mut self, id: SegmentId) -> Option<&mut Segment<R>> {
for s in &mut self.segments {
if s.is(id) {
return Some(s);
}
}
None
}
fn peek_val(&self, addr: u16) -> Result<u8, Option<(R, u16)>> {
for segment in &self.segments {
if segment.position <= addr && addr - segment.position < segment.size {
return match &segment.mem {
Data::RAM(items) => Ok(items[(addr - segment.position) as usize]),
Data::ROM(items) => Ok(items[(addr - segment.position) as usize]),
Data::Reg(r) => Err(Some((*r, addr - segment.position))),
Data::Mirror(pos) => {
let offset = addr - segment.position;
self.peek_val(pos + offset)
} // Data::Disabled => Err(None),
};
}
}
Err(None)
}
}
impl<R: Copy> Memory for MemoryMap<R> {
fn peek(&self, addr: usize) -> Option<u8> {
self.peek_val(addr as u16).ok()
}
fn len(&self) -> usize {
self.segments
.iter()
.map(|s| s.position as usize + s.size as usize)
.max()
.unwrap_or(0)
}
fn edit_ver(&self) -> usize {
self.edit_ver
}
}
bitfield! {
#[derive(Clone, Copy, PartialEq, Eq)]
struct ShiftPair(u8);
impl Debug;
high, set_high: 7, 4;
low, set_low: 3, 0;
}
impl ShiftPair {
fn low_count(&self) -> usize {
if self.low() == 0 { 0 } else { 64 << self.low() }
}
fn high_count(&self) -> usize {
if self.high() == 0 {
0
} else {
64 << self.high()
}
}
}
#[derive(Clone, Copy, PartialEq, Eq)]
struct Mapper {
is_nes_2: bool,
horizontal_name_table: bool,
mapper: u16,
sub_mapper: u8,
prg_rom_size: u8,
chr_rom_size: u8,
prg_nv_ram_size: ShiftPair,
chr_nv_ram_size: ShiftPair,
}
#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
enum SegmentId {
#[allow(unused)]
TestRam,
InternalRam,
InternalRamMirror,
PpuRegisters,
ApuIoRegisters,
PrgRom,
Nametable0,
Nametable1,
Nametable2,
Nametable3,
VramMirror,
PaletteControl,
PaletteMirror,
PpuRom,
PpuRam,
// CpuBank(u32),
PrgBank0,
PrgBank1,
ChrBank0,
ChrBank1,
NVRam,
}
impl fmt::Display for SegmentId {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "{self:?}")
}
}
#[derive(Debug, Clone)]
pub struct Mapped {
cpu: MemoryMap<CPUMMRegisters>,
ppu: MemoryMap<PPUMMRegisters>,
mapper: Remapper,
}
impl Mapped {
pub fn from_rom(rom: &[u8]) -> Self {
let (header, rom) = rom.split_at(0x10);
let nes_20 = header[7] & 0x0C == 0x08;
// assert!(nes_20, "Only supports nes 2.0 format");
// if header[6] & 0b11111110 != 0 {
// todo!("Support other mapper flags, {:08b}", header[6]);
// }
let mapper = if nes_20 {
assert_eq!(header[9], 0, "No support for larger PRG/CHR roms");
// assert_eq!(header[10], 0, "No support for PRG-RAM/EEPROM");
// assert_eq!(header[11], 0, "No support for CHR-RAM");
assert!(header[12] == 0 || header[12] == 2, "Only support NTSC NES");
Mapper {
is_nes_2: true,
horizontal_name_table: header[6] & (1 << 0) == 1,
mapper: ((header[6] as u16 & 0xF0) >> 4)
| ((header[7] as u16 & 0xF0) >> 0)
| ((header[8] as u16 & 0x0F) << 8),
sub_mapper: (header[8] & 0xF0) >> 4,
prg_rom_size: header[4],
chr_rom_size: header[5],
prg_nv_ram_size: ShiftPair(header[10]),
chr_nv_ram_size: ShiftPair(header[11]),
}
} else {
Mapper {
is_nes_2: false,
horizontal_name_table: header[6] & (1 << 0) == 1,
mapper: ((header[6] as u16 & 0xF0) >> 4) | ((header[7] as u16 & 0xF0) >> 0),
sub_mapper: 0,
prg_rom_size: header[4],
chr_rom_size: header[5],
prg_nv_ram_size: ShiftPair(0),
chr_nv_ram_size: ShiftPair(0),
}
};
let (prg_rom, rom) = rom.split_at(mapper.prg_rom_size as usize * 0x4000);
let (chr_rom, _rom) = rom.split_at(mapper.chr_rom_size as usize * 0x2000);
println!("Mapper: {}/{}", mapper.mapper, mapper.sub_mapper);
assert_eq!(
mapper.prg_nv_ram_size.low_count(),
0,
"No support for PRG-RAM"
);
// assert_eq!(
// mapper.chr_nv_ram_size.low_count(),
// 0,
// "No support for CHR-RAM"
// );
assert_eq!(
mapper.chr_nv_ram_size.high_count(),
0,
"No support for CHR-NVRAM"
);
// assert_eq!(rom.len(), 0);
// let prg_rom = &file[self.cpu_offset()..self.ppu_offset()];
let mut cpu_segments = vec![
Segment::ram(SegmentId::InternalRam, 0x0000, 0x0800),
Segment::mirror(SegmentId::InternalRamMirror, 0x0800, 0x1800, 0x0000),
Segment::reg(SegmentId::PpuRegisters, 0x2000, 0x0008, CPUMMRegisters::PPU),
Segment::reg(
SegmentId::ApuIoRegisters,
0x4000,
0x0018,
CPUMMRegisters::APU,
),
];
// CHR-NVRAM
if mapper.prg_nv_ram_size.high_count() > 0 {
cpu_segments.push(Segment::ram(
SegmentId::NVRam,
0x6000,
mapper.prg_nv_ram_size.high_count() as u16,
));
}
let mut ppu_segments = vec![
Segment::mirror(SegmentId::VramMirror, 0x3000, 0x0F00, 0x0000),
Segment::reg(
SegmentId::PaletteControl,
0x3F00,
0x0020,
PPUMMRegisters::Palette,
),
Segment::mirror(SegmentId::PaletteMirror, 0x3F20, 0x00E0, 0x3F00),
];
if mapper.horizontal_name_table {
ppu_segments.push(Segment::ram(SegmentId::Nametable0, 0x2000, 0x400));
ppu_segments.push(Segment::ram(SegmentId::Nametable1, 0x2400, 0x400));
ppu_segments.push(Segment::mirror(
SegmentId::Nametable2,
0x2800,
0x400,
0x2000,
));
ppu_segments.push(Segment::mirror(
SegmentId::Nametable3,
0x2C00,
0x400,
0x2400,
));
} else {
ppu_segments.push(Segment::ram(SegmentId::Nametable0, 0x2000, 0x400));
ppu_segments.push(Segment::mirror(
SegmentId::Nametable1,
0x2400,
0x400,
0x2000,
));
ppu_segments.push(Segment::ram(SegmentId::Nametable2, 0x2800, 0x400));
ppu_segments.push(Segment::mirror(
SegmentId::Nametable3,
0x2C00,
0x400,
0x2800,
));
}
let remap = if mapper.mapper == 0 {
cpu_segments.push(Segment::rom(
SegmentId::PrgRom,
0x8000 + (0x8000 - prg_rom.len() as u16),
prg_rom,
));
if mapper.is_nes_2 {
if mapper.chr_nv_ram_size.low_count() > 0 {
ppu_segments.push(Segment::ram(
SegmentId::PpuRam,
0,
mapper.chr_nv_ram_size.low_count() as u16,
));
} else {
ppu_segments.push(Segment::rom(SegmentId::PpuRom, 0, chr_rom));
}
} else {
if chr_rom.len() == 0 {
ppu_segments.push(Segment::ram(SegmentId::PpuRam, 0, 0x2000));
} else {
ppu_segments.push(Segment::rom(SegmentId::PpuRom, 0, chr_rom));
}
}
Remapper::None
} else if mapper.mapper == 1 && mapper.sub_mapper == 0 {
let prg_banks: Vec<Arc<[u8]>> =
prg_rom.chunks(0x4000).map(|ch| Arc::from(ch)).collect();
for (i, b) in prg_banks.iter().enumerate() {
println!("{i}: {:X?}", &b[0x3FF0..]);
}
cpu_segments.push(Segment::rom(
SegmentId::PrgBank0,
0x8000,
prg_banks.first().unwrap().clone(),
));
cpu_segments.push(Segment::rom(
SegmentId::PrgBank1,
0xC000,
prg_banks.last().unwrap().clone(),
));
println!("CHR_ROM: {}", chr_rom.len());
let chr_banks: Vec<Arc<[u8]>> =
chr_rom.chunks(0x1000).map(|ch| Arc::from(ch)).collect();
if chr_rom.len() == 0 {
ppu_segments.push(Segment::ram(SegmentId::PpuRam, 0, 0x2000));
} else {
ppu_segments.push(Segment::rom(
SegmentId::ChrBank0,
0x0000,
chr_banks[0].clone(),
));
ppu_segments.push(Segment::rom(
SegmentId::ChrBank1,
0x1000,
chr_banks[1].clone(),
));
}
Remapper::MMC1 {
shift_reg: 0,
count: 0,
prg_banks,
chr_banks,
mode: MMC1Mode::LastFixed,
cur_prg_bank: 0,
}
} else {
todo!()
};
Self {
cpu: MemoryMap {
edit_ver: 0,
segments: cpu_segments,
},
ppu: MemoryMap {
edit_ver: 0,
segments: ppu_segments,
},
mapper: remap,
}
}
pub fn power_cylce(&mut self) -> Self {
// TODO: mapper needs to reset cpu and ppu mem maps
let mut cpu = self.cpu.power_cycle();
let mut ppu = self.ppu.power_cycle();
Self {
mapper: self.mapper.power_cycle(&mut cpu, &mut ppu),
cpu,
ppu,
}
}
pub fn peek_ppu(&self, addr: u16) -> Result<u8, Option<(PPUMMRegisters, u16)>> {
self.ppu.peek_val(addr)
}
pub fn ppu_edit_ver(&self) -> usize {
self.ppu.edit_ver
}
pub fn peek_cpu(&self, addr: u16) -> Option<u8> {
self.cpu.peek_val(addr).ok()
}
pub fn cpu_edit_ver(&self) -> usize {
self.cpu.edit_ver
}
#[cfg(test)]
pub fn test_ram() -> Self {
Self {
cpu: MemoryMap {
edit_ver: 0,
segments: vec![Segment::ram(SegmentId::TestRam, 0, 0x8000)],
},
ppu: MemoryMap {
edit_ver: 0,
segments: vec![Segment::ram(SegmentId::TestRam, 0, 0x8000)],
},
mapper: Remapper::None,
}
}
}
pub struct CpuMem<'a> {
mem: &'a mut Mapped,
ppu: &'a mut PPU,
apu: &'a mut APU,
dma: &'a mut DmaState,
controllers: &'a mut Controllers,
}
impl<'a> CpuMem<'a> {
pub fn new(
mem: &'a mut Mapped,
ppu: &'a mut PPU,
apu: &'a mut APU,
dma: &'a mut DmaState,
controllers: &'a mut Controllers,
) -> Self {
Self {
mem,
ppu,
apu,
dma,
controllers,
}
}
pub fn read(&mut self, addr: u16) -> u8 {
match self.mem.mapper {
_ => (),
}
match self.mem.cpu.read(addr) {
Value::Value(v) => v,
Value::Register { reg, offset } => match reg {
CPUMMRegisters::PPU => self.ppu.read_reg(&mut PpuMem::new(self.mem), offset),
CPUMMRegisters::APU => {
if offset == 0x014 {
todo!("OAM DMA")
} else if offset == 0x16 {
self.controllers.read_joy1()
} else if offset == 0x17 {
self.controllers.read_joy2()
} else {
self.apu.read_reg(offset)
}
}
},
}
}
pub fn write(&mut self, addr: u16, val: u8) {
match &mut self.mem.mapper {
Remapper::MMC1 {
shift_reg,
count,
mode,
prg_banks,
chr_banks,
cur_prg_bank,
} if addr & 0x8000 != 0 => {
if val & 0x80 != 0 {
*shift_reg = 0;
*count = 0;
} else if *count == 4 {
let val = (*shift_reg >> 1) | ((val & 0x01) << 4);
if (addr & 0x6000) >> 13 == 0 {
// TODO: fix mem layout if it's changed
if val & 0b01100 == 0b01000 {
*mode = MMC1Mode::FirstFixed;
let bank0 = self.mem.cpu.find(SegmentId::PrgBank0).unwrap();
bank0.swap_rom(prg_banks[0].clone());
let bank1 = self.mem.cpu.find(SegmentId::PrgBank1).unwrap();
bank1.swap_rom(prg_banks[*cur_prg_bank].clone());
} else if val & 0b01100 == 0b01100 {
*mode = MMC1Mode::LastFixed;
let bank0 = self.mem.cpu.find(SegmentId::PrgBank0).unwrap();
bank0.swap_rom(prg_banks[*cur_prg_bank].clone());
let bank1 = self.mem.cpu.find(SegmentId::PrgBank1).unwrap();
bank1.swap_rom(prg_banks.last().unwrap().clone());
} else {
*mode = MMC1Mode::Full;
let bank0 = self.mem.cpu.find(SegmentId::PrgBank0).unwrap();
bank0.swap_rom(prg_banks[*cur_prg_bank & !1].clone());
let bank1 = self.mem.cpu.find(SegmentId::PrgBank1).unwrap();
bank1.swap_rom(prg_banks[(*cur_prg_bank & !1) + 1].clone());
}
if val & 0b10000 == 0b10000 {
// TODO: CHR-ROM mode
}
// TODO: Set name table mirroring
if val & 0b00011 == 0b00000 {
} else if val & 0b00011 == 0b00001 {
} else if val & 0b00011 == 0b00010 {
} else {
}
} else if (addr & 0x6000) >> 13 == 1 {
if chr_banks.len() != 0 {
todo!("Swap CHR bank 0")
}
} else if (addr & 0x6000) >> 13 == 2 {
if chr_banks.len() != 0 {
todo!("Swap CHR bank 1")
}
} else if (addr & 0x6000) >> 13 == 3 {
*cur_prg_bank = (val & 0x0F) as usize;
// println!("Updating ROM: new {:X}", val);
match mode {
MMC1Mode::Full => {
let bank0 = self.mem.cpu.find(SegmentId::PrgBank0).unwrap();
bank0.swap_rom(prg_banks[*cur_prg_bank & !1].clone());
let bank1 = self.mem.cpu.find(SegmentId::PrgBank1).unwrap();
bank1.swap_rom(prg_banks[(*cur_prg_bank & !1) + 1].clone());
}
MMC1Mode::FirstFixed => {
let bank1 = self.mem.cpu.find(SegmentId::PrgBank1).unwrap();
// Highest bit is ignored
bank1.swap_rom(prg_banks[(val & 0x07) as usize].clone());
}
MMC1Mode::LastFixed => {
let bank0 = self.mem.cpu.find(SegmentId::PrgBank0).unwrap();
// Highest bit is ignored
bank0.swap_rom(prg_banks[(val & 0x07) as usize].clone());
}
}
// TODO: handle MSB, changes some stuff...
} else {
todo!("Handle reg write {} => {}", val, (addr & 0x6000) >> 13,)
}
*shift_reg = 0;
*count = 0;
} else {
*shift_reg = (*shift_reg >> 1) | ((val & 0x01) << 4);
*count += 1;
// println!("Mapper SHR {:05b}", *shift_reg);
}
}
_ => (),
}
match self.mem.cpu.write(addr, val) {
Some((CPUMMRegisters::PPU, offset, val)) => {
self.ppu.write_reg(&mut PpuMem::new(self.mem), offset, val)
}
Some((CPUMMRegisters::APU, offset, val)) => {
if offset == 0x014 {
*self.dma = DmaState::Idle((val as u16) << 8);
} else if offset == 0x16 {
self.controllers.write_joy_strobe(val);
} else {
self.apu.write_reg(offset, val);
}
}
_ => (),
}
}
}
pub struct PpuMem<'a>(&'a mut Mapped);
impl<'a> PpuMem<'a> {
pub fn new(mem: &'a mut Mapped) -> Self {
Self(mem)
}
pub fn read(&mut self, addr: u16) -> Value<PPUMMRegisters> {
self.0.ppu.read(addr)
}
pub fn write(&mut self, addr: u16, val: u8, reg_fn: impl FnOnce(&PPUMMRegisters, u16, u8)) {
match self.0.ppu.write(addr, val) {
Some((r, o, v)) => reg_fn(&r, o, v),
None => (),
}
}
}
#[derive(Debug, Clone)]
enum MMC1Mode {
Full,
FirstFixed,
LastFixed,
}
#[derive(Debug, Clone)]
enum Remapper {
None,
MMC1 {
shift_reg: u8,
count: u8,
prg_banks: Vec<Arc<[u8]>>,
chr_banks: Vec<Arc<[u8]>>,
mode: MMC1Mode,
cur_prg_bank: usize,
},
}
impl Remapper {
fn power_cycle(
&mut self,
cpu: &mut MemoryMap<CPUMMRegisters>,
_ppu: &mut MemoryMap<PPUMMRegisters>,
) -> Self {
match self {
Remapper::None => Remapper::None,
Remapper::MMC1 {
prg_banks,
chr_banks,
..
} => {
let prg_banks = std::mem::take(prg_banks);
let chr_banks = std::mem::take(chr_banks);
cpu.find(SegmentId::PrgBank0)
.unwrap()
.swap_rom(prg_banks[0].clone());
cpu.find(SegmentId::PrgBank1)
.unwrap()
.swap_rom(prg_banks.last().unwrap().clone());
Remapper::MMC1 {
shift_reg: 0,
count: 0,
prg_banks,
chr_banks,
mode: MMC1Mode::LastFixed,
cur_prg_bank: 0,
}
}
}
}
}