Blumoto vs Opcodes
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Blumoto
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A Heathkit ET-3400 Simulator. The app simulates a Heathkit ET-3400. This was an inexpensive computer from 1977 for people to learn about computing and programming. With the app you can enter programs in machine code using the keypad and see the result on the 6 LED digits. It emulates the Motorola 6800 8 bit processor and contains the original ROM and 256 bytes of RAM
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 in-app purchases: Blumoto at none against Opcodes's 1. Blumoto also leads on iOS requirement (15.0 vs 18.0). Opcodes's advantage is update cadence (every 8 days vs every 20 months). On price, ads and device support 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. Opcodes sells 1 one-off in-app purchase. Blumoto asks for nothing beyond the download.
Blumoto ships an update every 20 months, Opcodes every 8 days. The most recent releases landed on September 9, 2026 and September 20, 2026 respectively.
| Parameter | Blumoto | Opcodes |
|---|---|---|
| Price | Free | Free |
| Rating | — | 4.8 (6 ratings) — better |
| Number of ratings | — | 6 — better |
| Update frequency | Every 20 months | Every 8 days — better |
| Ads | No | No |
| In-app purchases | No — better | Yes |
| Monetization | — | Free |
| Devices | iPhone, iPad, iPod — better | iPhone, iPad |
| Requires iOS | 15.0 — better | 18.0 |
| Further details — not scored | ||
| Size | 65 MB | 58 MB |
| Age rating | 4+ | 4+ |
| Developer | Martin Gernss | John Kennedy |
In-app purchases
Blumoto
No in-app purchases
Opcodes
- Buy Me a Coffee$0.99







