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0.11

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SixtyPical

Version 0.11. 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.

Documentation

TODO

low and high address operators

To turn word type into byte.

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!)

Routine-local static memory locations

These would not need to appear in the inputs/outputs/trashes sets of the routines that call this routine.

These might be forced to specify an initial value so that they can always be assumed to be meaningful.

More modes for copy

Union rule for trashes in if

If one branch trashes {a} and the other branch trashes {b} then the whole if statement trashes {a, b}.

And at some point...