SixtyPical
==========

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

*   you forgot to clear carry before adding something to the accumulator
*   a subroutine that you call trashes a register you thought was preserved

and suchlike.

It is a **work in progress**, currently at the **proof-of-concept** stage.

The current released version of SixtyPical is 0.5.  The current development
version of SixtyPical, unreleased as of this writing, is 0.6-PRE.

Documentation
-------------

*   Design Goals — coming soon.
*   [SixtyPical specification](doc/SixtyPical.md)
*   [SixtyPical history](HISTORY.md)
*   [Literate test suite for SixtyPical syntax](tests/SixtyPical Syntax.md)
*   [Literate test suite for SixtyPical execution](tests/SixtyPical Execution.md)
*   [Literate test suite for SixtyPical analysis](tests/SixtyPical Analysis.md)
*   [Literate test suite for SixtyPical compilation](tests/SixtyPical Compilation.md)
*   [6502 Opcodes used/not used in SixtyPical](doc/6502 Opcodes.md)

TODO
----

For 0.6:

*   declared `inputs` `outputs` `trashes` on the `vector` type...
    *   we need to get these 3 things onto the type, and also onto routine types
*   `goto` (tail call) a routine or a vector.
*   A more involved demo for the C64 — one that sets up an interrupt.

For 0.7:

*   `word` type.
*   `trash` instruction.
*   zero-page memory locations.
*   indirect addressing.

At some point...

*   `interrupt` routines.
*   add line number (or at least routine name) to error messages.
*   6502-mnemonic aliases (`sec`, `clc`)
*   other handy aliases (`eq` for `z`, etc.)
*   have `copy` instruction able to copy a constant to a user-def mem loc, etc.
*   add absolute addressing in shl/shr, absolute-indexed for add, sub, etc.
*   check and disallow recursion.