The Assembler vs Opcodes
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
The Assembler
Learn Assembly programming and binary operations by creating pixel art. Each chapter introduces new operations, using 8-bit registers as your canvas to manipulate values and paint an 8x8 image. This app offers a fun, introductory approach to coding fundamentals.
- Learn Assembly programming
- Understand binary operations
- Create pixel art on registers
- Ten chapters with progressive learning
- Interactive 8x8 canvas
- Introduction to programming fundamentals
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Learn Assembly programming and binary operations by painting little pixel art pieces. The app teaches different operations in each of the ten chapters. For each of the chapters you program an image with a limited set of commands. Eight rows of 8-Bit Registers turn into your canvas. Use Assembly to manipulate the values in every register, thus creating an 8x8 painting. 'The Assembler' was made as a small and fun introduction to Assembly, Programming and the Binary system that powers it all. The first version of this app was made for the Swift Student Challenge 2022 and won! I hope that you enjoy this project as much as I have.
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: The Assembler at none against Opcodes's 1. Opcodes's advantage is update cadence (every 8 days vs every 5 months). On price, rating, ratings volume and ads 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. The Assembler asks for nothing beyond the download.
On the App Store both sit at effectively the same score — 4.8 for The Assembler against 4.8 for Opcodes. Both are backed by a comparable volume of ratings — 10 and 6 respectively.
The Assembler ships an update every 5 months, Opcodes every 8 days. The most recent releases landed on September 27, 2026 and October 7, 2026 respectively.
| Parameter | The Assembler | Opcodes |
|---|---|---|
| Price | Free | Free |
| Rating | 4.8 (10 ratings) | 4.8 (6 ratings) |
| Positive reviews | 77.8% of reviews | — |
| Number of ratings | 10 — better | 6 |
| Update frequency | Every 5 months | Every 8 days — better |
| Ads | No | No |
| In-app purchases | No — better | Yes |
| Monetization | Free | Free |
| Devices | iPhone, iPad, Vision Pro — better | iPhone, iPad |
| Requires iOS | 17.0 — better | 18.0 |
| Further details — not scored | ||
| Size | 7 MB | 58 MB |
| Age rating | 4+ | 4+ |
| Developer | Lena Mattea Stoexen | John Kennedy |
Customer experience
The Assembler
Opcodes
In-app purchases
The Assembler
No in-app purchases
Opcodes
- Buy Me a Coffee$0.99








