What was the first publication to document what is (now) known as AT&T syntax assembly language?


1 Answer 1


As sampablokuper (OP) has noted, the UNIX Programmer's Manual cites PAL-11R as the source of the syntax, with only minor changes. So I've found a published book from May 1971, the PAL-11R Assembler Programmer's Manual that describes the syntax. Given that the syntax was probably around in 1969, this is still almost definitely not the earliest.

The earliest I can find with a casual web search is the UNIX Programmers Manual of November 1971 (better version). If you scroll to page 195 (page 5), you'll see this:

173700: mov      $177472,r0                   12700;177472
        mov      $3,—(r0)                     12740;3
        mov      $140000,—(r0)                12740;140000
        mov      $54000,—(r0)                 12740;54000
        mov      $—2000,—(r0)                 12740;176000
        mov      $5,—(r0)                     12740;5
        tstb     (r0)                         105710
        bge      .—2                          2376
        jmp      *$5400Q                      137;54000

173740: mov      $177350,r0                   12700;177350
        clr      —(r0)                        5040
        mov      r0,—(r0)                     10040
        mov      $3,—(r0)                     12740;3
        tstb     (r0)                         105710
        bge      .—2                          2376
        tst      *$177350                     5737;177350
        bne      .                            1377
        movb     $5,(r0)                      112710;5
        tstb     (r0)                         105710
        bge      .—2                          2376
        clr      pc                           5007

That, if I'm not mistaken, is AT&T syntax!

The earliest paper on UNIX, according to this source, is this paper. This document is from July 1974, so it's no good as a first, and does not include any AT&T syntax anyway. It does, however, state that the first version of UNIX was made circa. 1969–1970. This isn't necessarily a limit on the earliest that the syntax could've been described in a publication, since it might predate UNIX; I don't know.

  • Thanks! I had not previously seen mov used by itself in AT&T assembly code (always movb, movl, etc.), but that does not mean mov was (is?) not valid AT&T syntax. (I am new to the syntax.) I will upvote this and provisionally mark it as correct. If any other answers come along, with earlier examples, I will move the "correct" mark accordingly.
    – user11467
    Dec 30, 2018 at 23:27
  • 1
    On page 21 of the first PDF in your answer, the man page for as states, "as is based on the DEC-provided assembler PAL-11R, although it was coded locally. Therefore, only the differences will be recorded [in this man page]." The differences seem fairly minor. So, it seems that what we now call "AT&T syntax" is largely due to DEC rather than AT&T. Interesting.
    – user11467
    Dec 31, 2018 at 0:23
  • 4
    DEC used #foo for an immediate operand in -11 assemblers; the Unix guys apparently preferred $foo, which to my eyes lacks any mnemonic significance. Similarly @ became *. Does anyone know the rationale or is this just personal taste?
    – dave
    Dec 31, 2018 at 15:19
  • 2
    @another-dave Ask a new question and more people will see this to be able to answer it.
    – wizzwizz4
    Dec 31, 2018 at 15:47
  • 1
    @another-dave: # and @ were apparently hard to type (Unix Assembler Reference Manual §8.1 - Dennis M. Ritchie, referenced in my answer of stackoverflow.com/questions/4193827/…), fuz says "As the UNIX tty driver used @ and # as control characters, $ was substituted for # and * for @. at stackoverflow.com/questions/42244028/…
    – ninjalj
    Jan 1, 2019 at 13:06

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