Kim6502 vs Opcodes
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Kim6502
This app simulates the KIM-1 single-board computer from 1976, featuring a 6502 microprocessor. Users can enter and run machine code, with programs starting at 0x0200 and a virtual tape for saving work. It includes built-in instructions for guidance.
- KIM-1 computer emulation
- 6502 microprocessor simulation
- Machine code entry and execution
- Program storage up to 0x0200 bytes
- Virtual tape for saving work
- Included instructions
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Kim6502 emulates the KIM-1 single board computer released in 1976 by MOS Technology. This computer has a 6502 microprocessor. With Kim6502 you can enter and run machine code just like you did on the Kim-1. Like on the Kim-1, your programs start at 0x0200 and can be up to 0x0200 bytes long. Instructions are included in the app, along with a virtual tape to save your work. https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
Opcodes
This app provides a comprehensive reference for retro CPU opcodes, including detailed descriptions, assembly examples, and historical context. It covers eighteen iconic processors and offers features like search, sorting, and filtering for easy exploration of historical computing information.
- Opcode reference for 18 iconic processors
- Detailed instruction descriptions
- Hex, octal, decimal values
- Flags affected, addressing modes, cycle counts
- Assembly code examples
- CPU history and pinout diagrams
- Simple assembler/disassembler
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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
Screenshots
Verdict
The clearest difference is monetization model: Opcodes at free against Kim6502's free with in-app purchases. Opcodes also leads on ratings volume (6 vs 1). On price, rating, ads and in-app purchases there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. Kim6502 sells 1 in-app purchase, starting at $5.99 per year and Opcodes sells 1 one-off in-app purchase. Whichever you choose, the download price is not the number that matters.
Kim6502 holds the better App Store score, 5.0 against 4.8. That said, the two scores are not equally well evidenced: Opcodes has 6 ratings behind it against 1, so its average is the more settled of the two.
| Parameter | Kim6502 | Opcodes |
|---|---|---|
| Price | Free | Free |
| Rating | 5.0 (1 ratings) — better | 4.8 (6 ratings) |
| Number of ratings | 1 | 6 — better |
| Update frequency | — | Every 8 days |
| Ads | No | No |
| In-app purchases | Yes | Yes |
| Monetization | Free with in-app purchases | Free — better |
| Devices | iPhone, iPad | iPhone, iPad |
| Requires iOS | 18.0 | 18.0 |
| Further details — not scored | ||
| Size | 1 MB | 58 MB |
| Age rating | 4+ | 4+ |
| Developer | Michael Herman | John Kennedy |
In-app purchases
Kim6502
- Kim6502 annual subscription$5.991 Year
Opcodes
- Buy Me a Coffee$0.99









