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Re: Can't Avoid That Shit Rust - Even On Gentoo

From Rich Alderson <news@alderson.users.panix.com>
Newsgroups comp.os.linux.advocacy, comp.os.linux.misc, alt.folklore.computers
Subject Re: Can't Avoid That Shit Rust - Even On Gentoo
Followup-To alt.folklore.computers
Date 2024-10-06 19:59 -0400
Organization PANIX Public Access Internet and UNIX, NYC
Message-ID <mdd34l84waz.fsf@panix5.panix.com> (permalink)
References (2 earlier) <pan$3ac1d$92afd8da$2552f614$ebf3c267@gnu.rocks> <PL-dncdcxJXTlJ_6nZ2dnZfqnPadnZ2d@earthlink.com> <SMpMO.249150$v8v2.8876@fx18.iad> <lmeosnFmgllU1@mid.individual.net> <vdv6h5$1dc01$6@dont-email.me>

Cross-posted to 3 groups.

Followups directed to: alt.folklore.computers

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Lawrence D'Oliveiro <ldo@nz.invalid> writes:

> On 6 Oct 2024 06:26:32 GMT, rbowman wrote:

>> ... as I recall you could twiddle octal locations in the opcodes.

> Sounds PDP-11-ish. The instruction layout was such that, if an instruction 
> was expressed as an integer, register numbers and addressing modes fitted 
> neatly into particular octal digits.

> Not sure if that was true of the PDP-10. The later VAX went all hex, of 
> course.

The PDP-10 instruction layout is

		    1 1 1  1 1 2         3    3
	0......8 9..2 3 4..7 890123456789012345
	op code   AC  I  IX   address offset

All represented in octal.  The HALT instruction (a variant on the JRST) is a
good example:

	HALT RESUME(17)		;RESUME is a symbolic address, let's say 654321

The assembly representation is

	254 04 0 17 654321

The in-memory representation is 254217654321.  Patching from the front panel of
a 166, KA-10, or KI-10 processor is simple enough, if you know where your program
lives in memory (not a given, since the entire line is intended for multiuser
usage).

-- 
Rich Alderson					  news@alderson.users.panix.com
      Audendum est, et veritas investiganda; quam etiamsi non assequamur,
	  omnino tamen proprius, quam nunc sumus, ad eam perveniemus.
									--Galen

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Thread

Re: Can't Avoid That Shit Rust - Even On Gentoo "186282@ud0s4.net" <186283@ud0s4.net> - 2024-10-05 23:51 -0400
  Re: Can't Avoid That Shit Rust - Even On Gentoo Charlie Gibbs <cgibbs@kltpzyxm.invalid> - 2024-10-06 06:05 +0000
    Re: Can't Avoid That Shit Rust - Even On Gentoo rbowman <bowman@montana.com> - 2024-10-06 06:26 +0000
      Re: Can't Avoid That Shit Rust - Even On Gentoo Charlie Gibbs <cgibbs@kltpzyxm.invalid> - 2024-10-06 18:44 +0000
      Re: Can't Avoid That Shit Rust - Even On Gentoo Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-10-06 23:29 +0000
        Re: Can't Avoid That Shit Rust - Even On Gentoo Rich Alderson <news@alderson.users.panix.com> - 2024-10-06 19:59 -0400
    Re: Can't Avoid That Shit Rust - Even On Gentoo David Lesher <wb8foz@panix.com> - 2024-10-07 14:42 +0000
      Re: Can't Avoid That Shit Rust - Even On Gentoo Chris Ahlstrom <OFeem1987@teleworm.us> - 2024-10-07 16:24 -0400
        Re: Can't Avoid That Shit Rust - Even On Gentoo "186282@ud0s4.net" <186283@ud0s4.net> - 2024-10-11 00:56 -0400
          Re: Can't Avoid That Shit Rust - Even On Gentoo Chris Ahlstrom <OFeem1987@teleworm.us> - 2024-10-11 11:01 -0400
  Re: Can't Avoid That Shit Rust - Even On Gentoo Peter Flass <peter_flass@yahoo.com> - 2024-10-06 15:58 -0700
    Re: Can't Avoid That Shit Rust - Even On Gentoo "186282@ud0s4.net" <186283@ud0s4.net> - 2024-10-11 00:53 -0400

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