Self modifying code, lambda calculus - Re: ENIAC programming

Chuck Guzis cclist at
Thu Sep 17 16:09:44 CDT 2015

> On Sep 17, 2015, at 2:56 PM, dwight <dkelvey at> wrote:
> What is the definition of self modifying? Is it changing an
> instruction to execute in the thread to be run? How about adding or
> subtracting something to be done in an execution queue?

What he said.  In the narrow viewpoint, "self-modifying" could be 
construed as "altering the order of instruction execution based on 
computational results "

I'm sure that there are those who would consider the "Execute" 
instruction on the S/360 machine (and lots of others) to be 
self-modifying code.

Others would consider only those cases where executed code is actually 
modified actively (e.g. doing I/O to a variable port number on an 8080. 
   The 8080 has only two I/O instructions (IN and OUT); both take an 
immediate (literal) operand).

The difference between the three cases, is, to my mind inconsequential.


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