17 Sep
2015
17 Sep
'15
4:42 p.m.
On 2015-09-18 01:29, Dave G4UGM wrote:
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: bqt at softjar.se || Reading murder books
pdp is alive! || tryin' to stay hip" - B. Idol
-----Original Message-----
From: cctalk [mailto:cctalk-bounces at classiccmp.org] On Behalf Of Johnny
Billquist
Sent: 18 September 2015 00:12
To: cctalk at classiccmp.org
Subject: Re: Self modifying code, lambda calculus - Re: ENIAC programming
On 2015-09-17 18:30, Dave G4UGM wrote:
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..... > -----Original Message-----
> From: cctalk [mailto:cctalk-bounces at classiccmp.org] On Behalf Of Paul
> Koning
> Sent: 17 September 2015 17:02
> To: General Discussion: On-Topic and Off-Topic Posts
> <cctalk at classiccmp.org>
> Subject: Re: Self modifying code, lambda calculus - Re: ENIAC
> programming
>
>
>> On Sep 16, 2015, at 11:36 PM, ben <bfranchuk at 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.