From: Clem Cole <clemc@ccc.com>
To: Warner Losh <imp@bsdimp.com>
Cc: The Eunuchs Hysterical Society <tuhs@tuhs.org>
Subject: [TUHS] Re: origin of null-terminated strings
Date: Fri, 16 Dec 2022 16:49:54 -0500 [thread overview]
Message-ID: <CAC20D2OBc71sa+7sUu_SsF3K4opF2wXaYGb_tn_1c4j7GPqUDA@mail.gmail.com> (raw)
In-Reply-To: <CAC20D2O-m40zLg62r=+Gm1t6tFLfuy4O4BG3iJj=1uuRXfKpmg@mail.gmail.com>
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More info WRT to historical DEC usage ...
---------- Forwarded message ---------
From: Bob Supnik
Date: Fri, Dec 16, 2022 at 4:39 PM
Subject: Re: Origin of ASCIZ / null terminated char arrays.
To: Clem Cole
It wasn't in the PDP8. The PDP8 mostly used sixbit, the ASCII subset
between 40 and 137. The character was simply masked by 077, so that 100
(@) became 0 and could be used as the delimiter. PAL8 (in OS8) does not
have a text generation pseudo-op.
The PDP7 had a TEXT pseudo-op that <did> fill an extra word with 0s if
the string was a multiple of 3 characters. It supported FIODEC, BAUDOT,
and ANALEX encodings, but not ASCII.
The PDP9 has both .SXBIT and .ASCII. The latter used two 18-bit words to
hold five 7bit ASCII characters. In both cases, words were zero-filled,
but an extra (word) of 0s was not added if the string was a multiple of
2/multiple of 5 characters.
The PDP11 had .ASCIZ, starting with Macro11 in 1972.
Tim can comment on the PDP10.
> ᐧ
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next prev parent reply other threads:[~2022-12-16 21:51 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-12-16 3:02 [TUHS] " Douglas McIlroy
2022-12-16 3:14 ` [TUHS] " Ken Thompson
2022-12-16 9:13 ` Dr Iain Maoileoin
2022-12-16 13:42 ` Dan Halbert
2022-12-16 16:10 ` Dan Cross
2022-12-16 16:22 ` Tom Lyon
2022-12-16 16:29 ` Jon Steinhart
2022-12-16 20:12 ` Dave Horsfall
2022-12-16 21:02 ` Warner Losh
2022-12-16 21:13 ` Clem Cole
2022-12-16 21:49 ` Clem Cole [this message]
2022-12-17 0:26 ` Phil Budne
2022-12-16 21:18 ` Luther Johnson
2022-12-16 21:20 ` Dan Halbert
2022-12-16 3:17 ` Steve Nickolas
2022-12-16 17:24 ` John P. Linderman
[not found] ` <6009124d-750d-365e-a424-ec7bb25922b9@gmail.com>
2022-12-16 22:30 ` [TUHS] Terms for string, and similar character constructs (was: origin of null-terminated strings) Alejandro Colomar
2022-12-16 22:51 ` [TUHS] " Dave Horsfall
2022-12-16 22:26 [TUHS] Re: origin of null-terminated strings Douglas McIlroy
2022-12-17 2:03 ` James Frew
2022-12-17 3:42 ` steve jenkin
2022-12-17 17:11 ` Clem Cole
2022-12-17 18:15 ` Tom Lyon
2022-12-17 18:43 ` Clem Cole
2022-12-17 18:46 ` Clem Cole
2022-12-17 19:26 ` Tom Perrine
2022-12-19 4:26 ` Adam Thornton
2022-12-16 23:11 Noel Chiappa
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