DEC Opcodes

Reference for DEC computers

Free · In‑App Purchases · Designed for iPad

Back when computers came with ash-trays. 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 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 More than just 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 Built for exploration:  • Search across all systems instantly  • 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 journey through the machines that made modern computing possible.

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Updated PDP-1 mnemonics for IOT and PDP-1D. Fixed crashing bug when running app on an Apple Silicon Mac.

Version 1.2

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    Information

    • Seller
      • John Kennedy
    • Size
      • 11.6 MB
    • Category
      • Education
    • Compatibility
      Requires iOS 18.0 or later.
      • iPhone
        Requires iOS 18.0 or later.
      • iPad
        Requires iPadOS 18.0 or later.
      • Mac
        Requires macOS 15.0 or later and a Mac with Apple M1 chip or later.
      • Apple Vision
        Requires visionOS 2.0 or later.
    • Languages
      • English
    • Age Rating
      4+
    • In-App Purchases
      Yes
    • Copyright
      • © 2026 John Kennedy
  • Developer Website
  • Privacy Policy

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