1 unstable release
0.1.0-alpha | Sep 24, 2023 |
---|
#134 in #emulation
59KB
1K
SLoC
6502 emulator
Please note that this is just a project for me to learn Rust and how the 6502 works. You can use this software, as-is. Feel free to submit issues and/or contribute, but don't expect too much.
Roadmap
- Come up with better Crate name
Backend
Core
- Implement all addressing modes
- Test all addressing modes
- Implement all instructions
- SBC
- Handle over/underflow in branching instructions
- Test all instructions
- Interrupts
- BRK
- IRQ
- NMI
- Test all opcodes
- Count cycles
IO
- Read plaintext files
- Read ROM files
- Custom, minimal format
- iNES
- NES2.0
NES
- PPU
- APU
- etc.
Frontend
- TUI
- Registers
- Flags
- Memory
- View memory
- Scroll memory
- Edit memory
- View stack
- Port to
ratatui
- Display
- Menus
- Theming
- API
Specific system emulation
- 0xFFFA-0xFFFB: NMI interrupt vector
- 0xFFFC-0xFFFD: reset vector
- 0xFFFE-0xFFFF: IRQ interrupt vector
Nintendo Entertainment System / Famicom
See NESdev Wiki for more.
CPU memory map
- 0x0000-0x07FF: 2KB internal RAM (as used in Bus.rs)
- 0x0800-0x1FFF: mirrors of internal RAM
- 0x2000-0x2007: PPU registers
- 0x2008-0x3FFF: mirrors of PPU registers
- 0x4000-0x4017: APU and I/O registers
- 0x4016 and 0x4017 read controller 1 and 2 (respectively), bit by bit
- 0x4018-0x401F: normally disabled (APU and I/O functionality)
- 0x4020-0xFFFF: cartridge space (PRG ROM/RAM and mapper registers, incl. reset and IRQ vector)
CPU-PPU registers
8 registers from 0x2000 to 0x2007, mirrored beyond that.
- 0x2000: PPUCTRL
- 0x2001: PPUMASK
- 0x2002: PPUSTATUS
- 0x2003: OAMADDR
- 0x2004: OAMDATA
- 0x2005: PPUSCROLL
- 0x2006: PPUADDR
- 0x2007: PPUDATA
- 0x4014: OAMDMA
PPU memory map
- 0x0000-0x1FFF: pattern memory ("CHR ROM")
- 0x2000-0x3EFF: nametable memory ("VRAM")
- 0x3F00-0x3FFF: palette memory
Dependencies
~11–20MB
~268K SLoC