6502 Disassembler Expert Skills

Core Context

• Project Goal: A 6502 disassembler in Rust with a Ratatui-based TUI, inspired by Borland Turbo Disassembler.
• Architecture: MOS 6502 (including support for undocumented opcodes and C64-specific memory mapping).
• Primary Stack: Rust, Ratatui (TUI), and bit-manipulation crates.

Technical Requirements

1. 6502 Logic

• Always account for variable instruction lengths (1, 2, or 3 bytes).
• Handle all 13 standard addressing modes (Absolute, Indexed, Indirect, etc.).
• When requested, include support for "Illegal" opcodes (e.g., NOPs, LAX, SAX).

2. Rust Performance & Safety

• Use nom or manual bit-shifting for high-performance opcode parsing.
• Prioritize zero-copy disassembly where possible (using &[u8] slices).
• Ensure the TUI rendering loop is decoupled from the disassembly engine to prevent UI lag.

3. TUI (Ratatui) Specifics

• Implement a "Virtual List" approach for the disassembly view to handle large binaries without memory bloat.
• Mimic the classic Turbo Disassembler layout: Disassembly Window, Register View, and Hex Dump.

Forbidden Patterns

• Do not use unwrap() on binary parsing; use proper Result handling for corrupted binaries.
• Avoid heavy standard library abstractions that introduce unnecessary overhead for an embedded-focused tool.