In the first version (+ 1 2 3) is raw code, whereas in the second version it is data. By assuming the truth of this statement it can be argued that Lisp isn’t even homiconic. The code has the same representation as data in the sense that they are both lists/trees/S-expressions. But the fact that … Read more
Malbolge would be a good place to start. Every instruction is self-modifying, and it’s a lot of fun(*) to play with. (*) Disclaimer: May not actually be fun.
You might want to consider writing a virtual machine in C, where you can build your own self-modifying code. If you wish to write self-modifying executables, much depends on the operating system you are targeting. You might approach your desired solution by modifying the in-memory program image. To do so, you would obtain the in-memory … Read more
I think, you should check the MACHINE_CLEARS.SMC performance counter (part of MACHINE_CLEARS event) of the CPU (it is available in Sandy Bridge 1, which is used in your Air powerbook; and also available on your Xeon, which is Nehalem 2 – search “smc”). You can use oprofile, perf or Intel’s Vtune to find its value: … Read more
Turns out that the Wikipedia entry on “self-modifying code” has a great list: Semi-automatic optimization of a state dependent loop. Runtime code generation, or specialization of an algorithm in runtime or loadtime (which is popular, for example, in the domain of real-time graphics) such as a general sort utility preparing code to perform the key … Read more
wow, this turned out to be a lot more painful than I expected. 100% of the pain was linux protecting the program from being overwritten and/or executing data. Two solutions shown below. And a lot of googling was involved so the somewhat simple put some instruction bytes and execute them was mine, the mprotect and … Read more
There are many valid cases for code modification. Generating code at run time can be useful for: Some virtual machines use JIT compilation to improve performance. Generating specialized functions on the fly has long been common in computer graphics. See e.g. Rob Pike and Bart Locanthi and John Reiser Hardware Software Tradeoffs for Bitmap Graphics … Read more