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Version 0.18. Work-in-progress, everything is subject to change.

SixtyPical is a low-level programming language with advanced static analysis. Many of its primitive instructions resemble those of the 6502 CPU — in fact it is intended to be compiled to 6502 machine code — but along with these instructions are constructs which ease structuring and analyzing the code. The language aims to fill this niche:

SixtyPical gives the programmer a coding regimen on par with assembly language in terms of size and hands-on-ness, but also able to catch many ridiculous silly errors at compile time, such as

Many of these checks are done with abstract interpretation, where we go through the program step by step, tracking not just the changes that happen during a specific execution of the program, but sets of changes that could possibly happen in any run of the program.

SixtyPical also provides some convenient operations based on machine-language programming idioms, such as

SixtyPical is defined by a specification document, a set of test cases, and a reference implementation written in Python 2. The reference implementation can analyze and compile SixtyPical programs to 6502 machine code, which can be run on several 6502-based 8-bit architectures:

Quick Start

If you have the VICE emulator installed, from this directory, you can run

./ c64 eg/c64/hearts.60p

and it will compile the hearts.60p source code and automatically start it in the x64 emulator, and you should see:

Screenshot of result of running hearts.60p

You can try the script on other sources in the eg directory tree, which contains more extensive examples, including an entire game(-like program); see eg/ for a listing.