On 2015-09-18 01:29, Dave G4UGM wrote:
-----Original Message-----
From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Johnny
Billquist
Sent: 18 September 2015 00:12
To: cctalk@classiccmp.org
Subject: Re: Self modifying code, lambda calculus - Re: ENIAC programming
On 2015-09-17 18:30, Dave G4UGM wrote:
-----Original Message-----
From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Paul
Koning
Sent: 17 September 2015 17:02
To: General Discussion: On-Topic and Off-Topic Posts
<cctalk@classiccmp.org>
Subject: Re: Self modifying code, lambda calculus - Re: ENIAC
programming
On Sep 16, 2015, at 11:36 PM, ben <bfranc...@jetnet.ab.ca> wrote:
On 9/16/2015 9:25 PM, Toby Thain wrote:
On 2015-09-16 6:18 PM, Dave G4UGM wrote:
...
It is notable that in order to solve all problems, a computer must
permit self modifying code.
Is that true? AFAIK Lambda calculus can describe any computable
function (as can a Turing machine), and it has no concept of "self
modifying code".
I never studied any of that, but you do have to LOAD and RUN the
program ToSolveAnythingBut42 some how so I guess that would count
AS
Self Modifying Code.
"load" is an operation in a RAM stored program computer, sure. But
self- modifying code means a program that modifies its own code
during execution. That is a scheme that has on rare occasions been
used in
history.
I actually think its pretty common, at least on certain machines,
especially for character manipulation.
There are machines, I think the Honeywell L66 is one, which make
character sting moves interruptible by updating the addresses and
lengths as the instruction is executed.
Say what? So if you run through the code/function twice, it won't work?
That would be pretty ugly.
I never said self-modifying code was petty.....
True. But while I have worked a lot on machines where you did it, and I
have written more than my fair share of self-modifying code, I have not
before seen a machine where the code would get modified behind your back.
Oh well. I guess I should be happen I never had to deal with that
architecture. :-)
Johnny
--
Johnny Billquist || "I'm on a bus
|| on a psychedelic trip
email: b...@softjar.se || Reading murder books
pdp is alive! || tryin' to stay hip" - B. Idol
