F16A PDP-1 Instruction List 0

This document is a reference sheet for the Digital Equipment Corporation's PDP-1 computer, dated July 1963. It outlines various aspects of the PDP-1's architecture and instruction set, including:

1. Alphanumeric Codes: A mapping of characters (letters, numbers, punctuation, and control codes like Tab, Backspace) to their FIO-DEC and Concise Codes, noting some are for type-out only.
2. PDP-1 Instruction List: A core set of instructions with mnemonics, octal codes, a description of the operation (e.g., arithmetic, logical, data movement, flow control), and execution times in microseconds. It references other groups for more specialized operations.
3. IN-OUT Transfer Group (Basic List): Defines I/O operations (e.g., tape I/O, typewriter I/O, mode control) and provides "Status Register Definitions" which explain the meaning of I/O bits (0-6) related to hardware status and control flags (e.g., light pen strike, typewriter ready, sequence break mode).
4. Operate Group: A micro-program set of instructions for basic system control, such as clearing registers (AC, IO), halting the machine, complementing the accumulator, and setting/loading flags.
5. Shift Rotate Group: Explains shift (arithmetic, preserves sign) and rotate (logical) operations for the Accumulator (AC) and I/O registers, detailing how the number of steps is specified within the instruction.
6. Skip Group: Provides conditional skip instructions based on register status (e.g., AC zero/plus/minus), flag status, overflow conditions, or sense switch settings, with a note on reversing skip intent.