Pal12a Assembler

This document serves as the program library write-up for the PAL12A assembler, a 4K assembler optimized for the PDP-12 computer running under the DIAL-V2 monitor. It is based on MACRO-8 and provides several features previously unavailable in a Linctape-oriented assembler for small configurations, such as literals, off-page links, a core usage map, and specific new operators.

Key details of the document include:

• Compatibility: While PAL12A is largely compatible with DIAL, there are specific differences, including the addition of EXPUNGE and FIXTAB pseudo-ops, and specific requirements for defining opcodes at the beginning of a source program.
• Capacity: PAL12A holds approximately 320 (decimal) symbols in core, expandable with the EXPUNGE pseudo-op, making it significantly more efficient for symbol handling than the original DIAL assembler in non-disk systems.
• Operating Procedures: The document outlines the switch register options for controlling the assembler (e.g., binary output, core map, listing, etc.) and provides details on keyboard input commands for filenames and units.
• Output and Storage: It describes how the assembler generates error messages, binary files, core usage maps, and listings, noting that it manages tape usage differently than DIAL by not outputting "garbage" code.
• Assembly Instructions: The text provides a recommended procedure for assembling the PAL12A binary from its source files, including instructions for using the "ADD BINARY" command.