Opcodes

1.6 for
Free
0

0 Ratings

Update Date

2026-04-25

Size

48.5 MB

Opcodes Description
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 chip, with memory maps.
• 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.

Beautifully designed: 

• Clean, readable layout optimised for quick reference.
• Multiple colour themes.
• Full "dark mode" support.

Everything is included with absolutely no in-app purchase required.
Opcodes 1.6 Update
2026-04-25
Added information for ARM
Improved text sizing
Fixed some factual errors
More Information
Price:
Free
Version:
1.6
Size:
48.5 MB
Genre:
Education
Update Date:
2026-04-25
Developer:
John Kennedy
Language:
English

Safe to Download

AppPure.com and the download link of this app are 100% safe. The download link of this app will be redirected to the official App Store site, thus the app is original and has not been modified in any way.

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1.6 2026-04-25
Added information for ARM
Improved text sizing
Fixed some factual errors
1.5 2026-04-22
Added a timeline of CPUs and key computers.
Added a biography section of CPU pioneers.
Added the Transputer to the collection.
1.3 2026-04-06
Corrected issue with missing 68000 mnemonic.
Improved view on iPad.
Disassemble code by pasting in multiple hex values for many CPUs.
1.2 2026-03-26
This version corrects a few issues with some opcodes, but more importantly adds a top-trumps style card game for you to really nerd out about. Thanks for the idea Mr 8BitForce!
1.1 2026-03-19
Improved some themes to improve visibility.
Minor tweaks and fixes.
1.0 2026-03-18