DEC Opcodes

Reference for DEC computers

Free · In-App Purchases · Designed for iPad. Not verified for macOS.

Insane in the mainframe! Learn about classic computers from the 1960s and 70s, with interactive lessons, historical information and much more. 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 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.

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Thanks for your support! This update includes: • New lessons on programming the PDP-11 in assembly language • More historical documents and photos • A list of real world locations to see real PDP computers

Version 1.6

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    Information

    Size
    • 44.3 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
    Provider
    John Kennedy
    • John Kennedy has not identified itself as a trader for this app. If you are a consumer in the European Economic Area, consumer rights do not apply to agreements between you and the provider.
    Copyright
    • © 2026 John Kennedy
  • Developer Website
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