Opcodes vs Turing Lab

Opcodes – The Retro CPU Reference The definitive opcode reference for the legendary processors that launched the personal computer revolution. Whether you're a retrocomputing enthusiast, a student of computer history, writing code for classic hardware, or just a big old nerd - the Opcodes app gives you everything you need. Eighteen iconic processors covered: Intel 4004 · Intel 8008 · Intel 8080 · Intel 8085 · Intel 8088 · Zilog Z80 · Motorola 6800 · Intel 8085 · Motorola 6809 · MOS 6502 · Signetics 2650 · RCA 1802 - SC/MP · Motorola 68000 · Intel 8086 · WDC 65816 · Texas Instruments TMS9900 · INMOS Transputer · ARM2 For every opcode:  • Full description of what the instruction does. • Hex, octal, and decimal values. • Flags affected. • Addressing modes and cycle counts. • Assembly code examples - including loops, conditionals, and common patterns. More than just opcodes:  • CPU history and historical context. • IC pinout diagrams. • Notable systems that used each CPU, with memory maps and other background information. • Chip variants and successors. • A silly card game(!) • Simple assembler / disassembler for many CPUs. Built for exploration:  • Search for opcodes by name or category. • Sort by mnemonic, opcode byte, or category. • Filter by category, Quick Find with a colorful map. • Undocumented instructions clearly marked and optionally displayed. More than microprocessors:  • Information on key support chips: video, sound, memory and more. Cool design:  • Clean, readable layout optimised for quick reference. • Multiple colour themes. • Full "dark mode" support. Everything is included with absolutely no in-app purchase required. Recent additions: • Quiz game - test your CPU knowledge! • Share CPU cards - beautiful shareable images showing specs and history for any processor • External references - curated links to community resources for all 18 CPUs • "Opcodes display first" setting - choose whether selecting a CPU shows opcodes or info first • Chip-maker colour themes - Zilog, MOS Tech, and Motorola replace the old themes • Enhanced 6502 docs - JMP page boundary bug, BRK behaviour, and Read-Modify-Write quirks • Fixed Scratchpad hang when switching tabs

Turing Lab is a touch-friendly environment for studying automata and formal languages on iPhone, iPad, and Mac. Create finite automata and pushdown automata, run bounded simulations, inspect step traces, minimize DFAs, and explore conversions between automata, regular expressions, and grammars. Build single-tape and multi-tape Turing machines, organize reusable machine building blocks, inspect tape execution, and analyze bounded or cyclic runs. Edit context-free and unrestricted grammars. Explore CYK, LL, LR, bounded brute-force parsing, normal forms, FIRST/FOLLOW sets, guided derivations, and supported grammar/automata conversions. Design Mealy and Moore transducers, simulate generated output, and work with L-systems through bounded rewriting, examples, and turtle rendering. Practice the Pumping Lemma for regular and context-free languages. Validate, compare, simplify, generate, and convert regular expressions. Supported workspaces provide JFLAP XML, versioned JSON, SVG, or PNG operations according to each model. Compatibility diagnostics disclose unsupported or lossy fields instead of silently discarding them. Turing Lab runs its learning workflows locally and includes offline examples. It is designed for students, educators, researchers, classroom demonstrations, lab exercises, and self-study. Turing Lab is inspired by JFLAP and supports selected compatible workflows. It is not affiliated with, endorsed by, or an official release of JFLAP, Duke University, or Susan H. Rodger.