Pal III Symbolic Assembler

Summary

This manual provides the programming specifications and operating instructions for the PAL III Symbolic Assembler on the Digital Equipment Corporation PDP-8 computer.

Key components of the manual include:

• Introduction to Assembly: It details the benefits of using an assembler, such as the use of mnemonic operation codes and symbolic naming, which simplify programming and debugging compared to raw machine code.

• The Assembly Process: The system utilizes a three-pass assembly process:

  • Pass 1: Defines all symbols and constructs the symbol table.
  • Pass 2: Generates and punches the binary object tape.
  • Pass 3: Produces an optional assembly listing that displays the source code alongside the corresponding machine code.

• Source Language Rules: It outlines the syntax for the assembly language, including the use of the location counter, character sets, expression formation, and various pseudo-instructions (e.g., DECIMAL, OCTAL, EXPUNGE, FIXTAB) used to direct the assembler's behavior.

• Operating Instructions: Provides step-by-step guidance on loading the assembler, setting up peripheral devices (such as the 33 ASR or high-speed paper tape reader/punch), and executing the various assembly passes using the computer's switch register.
• Symbol Table Management: The manual explains how to customize and expand the assembler's permanent symbol table to include definitions for optional hardware peripherals (e.g., A/D converters, magnetic tape, line printers) to conserve memory for user-defined symbols.
• Appendices: Includes comprehensive lists of basic and extended symbols, as well as the ASCII character set used by the system.