Greg's LAP6-DIAL
PDP-12 assembly program
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LAP6-DIAL was the assembler development environment for the PDP-12. I used it at the University of Exeter between 1970 and 1972. This page collects some of my own experience and also information available elsewhere on the web.

The acronym was redundant. It expanded to “Language Assembly Program 6 Display Interactive Assembly Language”, narrowly missing the opportunity to become a palindrome. For the day the important thing was that it took advantage of the PDP-12's built-in CRT display and was thus an early example of a display editor. Most other small computers used a Teletype as an input device.

Unfortunately, the editor was closely coupled to the assembly language syntax. By default input on a new line started at column 9, the beginning of the op code field in LAP-III (the assembler proper). A label started in column 1 and was delimited by a trailing comma, so entering a comma slid everything left to the beginning of the the line. Similarly, a slash initiated a comment, so entering a slash moved the slash itself and the cursor to column 25. This was convenient for writing assembler programs, and a pain in the arse for anything else.

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