PDP-6 Instruction List

This document serves as a quick reference guide to the PDP-6 computer's instruction set and word formats. It outlines the structure of various data and instruction words, including those for general instructions, IOT (Input/Output Transfer), status, block transfer control, push-down pointers, two's complement data, byte pointers, and floating-point numbers. The instruction set is categorized into several functional groups:

• Boolean Operations: Includes SET, EQuiValence eXclusive OR, and AND inclusive OR, with options for manipulating zeros, ones, accumulator, memory, and their complements, supporting immediate or memory-based operations.
• Arithmetic Operations: Covers basic integer operations like ADD, SUBtract, MULtiply, and DIVide, along with their floating-point counterparts (Floating ADD, SUBtract, MultiPly, DIVide, SCale). It also details Arithmetic SHift, Logical SHift, and ROTate instructions. Operands can be immediate, memory, or both, with options for rounding or long formats for floating-point.
• Jumps, Pushdown, and I/O: Provides a variety of conditional SKIP and JUMP instructions based on comparisons (less, equal, greater), status flags (AR OV, AR CRY0, AR CRY1, PC Change), and accumulator tests. It also lists instructions for executing from memory, calling subroutines, saving/restoring program counter and accumulator, PUSH/POP operations, and conditional I/O operations.
• Test and Modify: Describes instructions for testing and modifying the accumulator using direct memory, swapped memory, or immediate values, allowing operations like setting to nothing, zeros, ones, or complement, and conditional skips.
• Data Transmission: Includes instructions for MOVing (negating, setting magnitude, swapping) data, exchanging accumulator and memory content, block transfers, and incrementing byte pointers for loading or depositing bytes.

The document essentially acts as an architectural overview and programming aid, illustrating the diverse capabilities of the PDP-6 instruction set.