CODEWITHSUNDEEP
optimizationcompiler-constructionembeddedself-modifying8-bit
hippietrail
hippietrail

Reputation: 16974

Are there modern compilers for high level languages on simple processors which produce self-modifying code?

Back in the days before caches and branch prediction, it was relatively common if not encouraged to make self-modifying code for certain kinds of optimizations. It was probably most common in games and demos written in assembler in the eras between 8-bit up to early 32-bit such as the Amiga.

I'm not sure if any compilers from those days emitted self-modifying assembler or machine code.

What I'm wondering is whether there are any current/modern compilers that do. Obviously it would be useless or too difficult on powerful processors with caches.

But What about the very many simple processors such as used in embedded systems? Is self modifying code considered a viable optimization strategy by any modern compilers for any simple / 8-bit / embedded processor?

There is a question with a similar title, "Is there any self-improving compiler around? ", but note that it's not about the same subject:

Please note that I am talking about a compiler that improves itself - not a compiler that improves the code it compiles.

Upvotes: 2

Views: 190

Answers (1)

Lundin
Lundin

Reputation: 213809

All embedded systems today use flash ROM. I believe Amiga and similar were RAM-based systems. The only way "self-modification" exists in embedded systems, is where you have boot loaders, that re-program certain parts of the flash depending on what program and/or functionality that should be used.

Apart from that, it doesn't make sense for the program to modify itself in runtime. Running code from RAM is generally discouraged, for safety reasons (potential of accidental modifications caused by bugs) and for electric reasons (RAM is volatile and far more sensitive to EMC than flash).

Upvotes: 4

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