F-16 PDP-1 Instruction List 09

This document is an "INSTRUCTION LIST" published by Digital Equipment Corporation in September 1961, serving as a programming reference for an early computer system. It details the machine's instruction set, specialized operation groups, and alphanumeric character encoding.

The document is organized into several key sections:

1. Instruction List: Presents a core set of over 20 fundamental machine instructions, each with a mnemonic (e.g., add Y, jmp Y), octal code, a description of its operation, and its execution time in microseconds (typically 5 or 10 usec). These include operations for arithmetic (addition, logical AND/OR/XOR, multiply, divide), data movement (load, deposit), and program control (jump, skip, index).

2. Skip Group: A set of conditional jump instructions (e.g., sma for skip on minus AC, szs for skip on ZERO sense switch). It notes that the intent of any skip instruction can be reversed by setting Bit 5.

3. Operate Group: Describes a "micro program set of instructions" (e.g., cla to clear AC, hlt to halt, nop for no operation). These are often combined low-level operations.

4. In-Out Transfer Group (Basic List): Instructions for handling input/output operations. This includes functions like changing data fields, checking status, displaying on a CRT, managing sequence break mode, and interacting with punched tape (reading/punching alphanumeric and binary data) and typewriter input/output. It notes that this group can be greatly expanded for optional I/O equipment.

5. Shift Rotate Group: Explains operations for manipulating bits within the Accumulator (AC) and I/O registers. It distinguishes between "shift" (arithmetic, sign bit unchanged) and "rotate" (logical, bits cycle in a closed ring including the sign), specifying the number of steps is determined by bits 9-17 of the instruction (up to 9 max).

6. Alphanumeric Codes: A table mapping various characters (lowercase and uppercase letters, numbers, punctuation, and control characters like Space, Tab, Carrier Return) to their corresponding FIO-DEC and Concise numerical codes, with some codes specifically marked for "type-out only, not on keyboard."

In summary, the document provides a comprehensive technical reference for programmers, detailing the machine's low-level instruction set, I/O capabilities, bit manipulation functions, and character encoding scheme of the Digital Equipment Corporation computer system from 1961.