DEC Opcodes
Not in any tracked top chart right now.
Updated 24 Oct 2026 · rankings refresh through the day
DeveloperJohn Kennedy
CategoryEducation
PriceFree
Released
Rating★ 5.0 (3)
Version1.9
Age rating4+
First seen by us
23 Oct 2026
Rating
5.0 ★
3 ratings
Measured
DEC Opcodes on the App Store
App details
App ID
6760246055
Publisher
John Kennedy
On the store since
Mar 2026
Under a year
Minimum OS
iOS 18.0+
iPhone XS and later
Devices
iPhone · iPad
Universal purchase
Content rating
4+
Languages
1
EN
Size
44 MB
Where it ranks now
Every top chart it appears in across 30 countries.
| Country | Charts | Rank |
|---|---|---|
| Not charting right now. | ||
Ratings
App Store, worldwide.
Rating
5.0 ★
3 ratings
Measured
Ratings
3
Measured
About DEC Opcodes
Dec Opcodes – DEC Architecture Reference
Before the microprocessor, there was DEC. The minicomputers built by Digital Equipment Corporation didn't just advance computing - they defined it. Unix was born on a PDP-7. Spacewar! ran on a PDP-1. The field of Artificial Intelligence was born on the PDP-10. The VAX powered universities and research labs worldwide for a generation.
DecOpcodes puts the complete instruction sets of these legendary machines in your pocket.
Five iconic architectures covered: PDP-1 (1960) · PDP-8 (1965) · PDP-10 (1966) · PDP-11 (1970) · VAX (1977)
For every instruction:
• Full description of what the instruction does
• Octal and hex encoding
• Flags affected
• Addressing modes, word count, and cycle counts
• Assembly code examples and implementation notes
But there is a lot more than just dry opcodes:
• Complete system specifications and register architecture
• Historical context and cultural impact
• Archival photographs - front panels, system cabinets, and more
• Notable installations and the systems they powered
• Architecture variants and successors
• Interactive lessons on assembly language and console operations (ideal if you have an PiDP emulator)
Built for exploration:
• Search across all systems instantly
• A simple assembler for PDP-1, -8 and -11 code
• Filter by instruction category
• Sort alphabetically or by category
• Favorite instructions for quick reference
Beautifully designed:
• System-specific accent colours
• Five themes including Terminal green and Blinkenlights orange
• Full Dark Mode support
From the 18-bit simplicity of the PDP-1 to the 32-bit sophistication of the VAX, DecOpcodes is a fascinating and interactive journey through the machines that made modern computing possible.
All features are free and unlocked. If you like the app you can always leave a nice review or tip the developer!
Before the microprocessor, there was DEC. The minicomputers built by Digital Equipment Corporation didn't just advance computing - they defined it. Unix was born on a PDP-7. Spacewar! ran on a PDP-1. The field of Artificial Intelligence was born on the PDP-10. The VAX powered universities and research labs worldwide for a generation.
DecOpcodes puts the complete instruction sets of these legendary machines in your pocket.
Five iconic architectures covered: PDP-1 (1960) · PDP-8 (1965) · PDP-10 (1966) · PDP-11 (1970) · VAX (1977)
For every instruction:
• Full description of what the instruction does
• Octal and hex encoding
• Flags affected
• Addressing modes, word count, and cycle counts
• Assembly code examples and implementation notes
But there is a lot more than just dry opcodes:
• Complete system specifications and register architecture
• Historical context and cultural impact
• Archival photographs - front panels, system cabinets, and more
• Notable installations and the systems they powered
• Architecture variants and successors
• Interactive lessons on assembly language and console operations (ideal if you have an PiDP emulator)
Built for exploration:
• Search across all systems instantly
• A simple assembler for PDP-1, -8 and -11 code
• Filter by instruction category
• Sort alphabetically or by category
• Favorite instructions for quick reference
Beautifully designed:
• System-specific accent colours
• Five themes including Terminal green and Blinkenlights orange
• Full Dark Mode support
From the 18-bit simplicity of the PDP-1 to the 32-bit sophistication of the VAX, DecOpcodes is a fascinating and interactive journey through the machines that made modern computing possible.
All features are free and unlocked. If you like the app you can always leave a nice review or tip the developer!
Latest updates
1.9
What's New in v1.9
• DEC Glossary - Searchable guide to 45+ terms across buses, memory, storage, I/O, processors, software, and DEC culture
• PDP-11 instructions added - MFPI, MFPD, MTPI, MTPD (previous-space memory access) and SPL (set priority level)
• Memory Maps corrected - Separate PDP-11/45 (256KB) and PDP-11/70 (4MB) layouts; KW11-L and KW11-P clocks added to I/O page; byte units for PDP-11 and VAX
• Official DEC handbooks linked - Architecture Handbook PDFs from bitsavers for all five systems in Programming Resources
• System landing page setting - Choose whether tapping a system opens the instruction list or the system info page
• PiDP-8 Quick Start expanded - OS/8 first commands, paper tape bootstrap sequence, Spacewar! controls, TSS/8 multi-user login, USB storage guide
• PDP-1 toggle programs fixed - Correct memory addresses and proper ADD-based counting loop
• Dynamic Type support - All sidebar and card text now scales with your preferred font size
• Accessibility improved - Better VoiceOver labels and touch targets throughout
• Faster launch - Removed artificial splash screen delay