PAL-11 Assembler Specification

This document is a March 1969 interoffice memorandum from D. Barlow detailing the specifications for the PAL-11 Assembler, designed for the PDP-11 computer.

The document covers the following key areas:

• Overall Description: PAL-11 is a multi-pass, absolute symbolic assembler implemented using the PDP-11 assembly language, capable of processing variable-length instructions on a 16-bit word length machine.
• Input Format: Describes the syntax for source images, including the four fields (LABEL, OPERATOR, OPERAND, and COMMENTS), addressing modes, and the use of labels and direct assignments.
• Assembly Directives: Details various commands for data generation (BYTE, WORD), text generation (ASCII), and program control (END, EOT, REG, MORG).
• Output: Explains the format of assembly listings, including error codes and the symbol table.
• Operating Procedure: Outlines the loading procedure, command string interpretation, and error recovery methods.
• Appendices: Provides tables for USA Standard ASCII character codes and PDP-11 machine codes (Binary, Operate, Subroutine Call, Unary, Rotate/Shift, Conditional Branches, and Execute groups).