git @ Cat's Eye Technologies SixtyPical / 0.12

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Version 0.12. Work-in-progress, everything is subject to change.

SixtyPical is a very low-level programming language, similar to 6502 assembly, with static analysis through abstract interpretation.

In practice, this means it catches things like

and suchlike. It also provides some convenient operations and abstractions based on common machine-language programming idioms, such as

The reference implementation can analyze and compile SixtyPical programs to 6502 machine code.



Save registers on stack

This preserves them, so that, semantically, they can be used later even though they are trashed inside the block.

Range checking in the abstract interpretation

If you copy the address of a buffer (say it is size N) to a pointer, it is valid. If you add a value from 0 to N-1 to the pointer, it is still valid. But if you add a value ≥ N to it, it becomes invalid. This should be tracked in the abstract interpretation. (If only because abstract interpretation is the major point of this project!)

Range-checking buffers might be too difficult. Range checking tables will be easier. If a value is ANDed with 15, its range must be 0-15, etc.

Re-order routines and optimize tail-calls to fallthroughs

Not because it saves 3 bytes, but because it's a neat trick. Doing it optimally is probably NP-complete. But doing it adeuqately is probably not that hard.

And at some point...