Convert

This document describes the CONVERT program, designed to translate LAP6 or LAP6-3L source code stored on a LINC tape into a suitable source format for use with the DIAL system on the PDP-12 computer.

The program requires a minimum PDP-12A configuration, a DIAL system tape containing CONVERT on Unit 0, and the LAP6 source tape on Unit 1. The operating procedure involves loading the necessary tapes, calling DIAL, clearing the work area, and then executing CONVERT. Users are prompted to enter the starting block number for the program translation via a scope questionnaire. Upon completion, CONVERT rewinds the LAP6 tape and prompts the user, offering two choices: either file the converted source program or replace the LAP tape with a DIAL system tape to assemble, obtain a listing, or edit the program. A critical warning advises removing the LAP tape before issuing assembly or listing commands to prevent accidental overwriting of filed programs.

CONVERT performs several key transformations:

• Converts LAP6 packed LINC code into packed ASCII source code.
• Reverses and formats LAP tag indicators to be compatible with DIAL.
• Initiates most lines with a TAB character.
• Inserts spaces after three-letter combinations.
• Changes specific characters (e.g., 'i' to 'I', 'u' to 'U', 'p' to '.').
• Reverses number-letter combinations for tag references.
• Inserts warning messages and equalities for old mnemonics.
• Translates ALT MODE/A and ALT MODE/B to TEXT >.
• Changes the LAP terminator code (77) to the DIAL source terminator ($).
• Ignores the first two words of a LAP6 source.
• Replaces square left brackets with slashes for comments and vertical bars with backslashes for specific operators.

The document also outlines several limitations, emphasizing that CONVERT handles only the major translation tasks. Users are responsible for adapting to differences between the LINC-8 and PDP-12/DIAL environments, which may cause issues with:

• Keyboard I/O (KBD errors).
• Operation code handling (OPR.n errors).
• Tape Read/Write operations due to differing file formats.
• Processor mode changes (EXC mnemonic).
• A-D sampling instructions (SAM n).
• Rearranged instruction elements in LAP6.
• QANDA subroutine calls and text mode data handling.
• Teletype input (LINC code vs. ASCII).
• Retrieval of block numbers (Z register vs. MQ register).