Tree @reform-loadngo (Download .tar.gz)
Version 0.19. Work-in-progress, everything is subject to change.
SixtyPical is a low-level programming language supporting a sophisticated static analysis. Its reference compiler can generate efficient code for several 6502-based target platforms while catching many common mistakes at compile-time, reducing the time spent in debugging.
Make sure you have Python (2.7 or 3.5+) installed. Then
clone this repository and put its
bin directory on your
executable search path. Then you can run:
If you have the VICE emulator installed, you can run
sixtypical --output-format=c64-basic-prg --run 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:
You can try
sixtypical --run on other sources in the
tree, which contains more extensive examples, including an entire
game(-like program); see eg/README.md for a listing.
SixtyPical aims to fill this niche:
- You'd use assembly, but you don't want to spend hours debugging (say) a memory overrun that happened because of a ridiculous silly error.
- You'd use C or some other "high-level" language, but you don't want the extra overhead added by the compiler to manage the stack and registers.
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.
Many of SixtyPical's primitive instructions resemble those of the [MOS Technology 6502] — it is in fact intended to be compiled to 6502 machine code. However, it also does provide some "higher-level" operations based on common 8-bit machine-language programming idioms, including
- copying values from one register to another (via a third register when there are no underlying instructions that directly support it)
- copying, adding, and comparing 16-bit values (done in two steps)
- explicit tail calls
- indirect subroutine calls
While a programmer will find these constructs convenient, their inclusion in the language is primarily to make programs easier to analyze.
Sophisticated static analysis
The language defines an effect system, and the reference compiler abstractly interprets the input program to check that it conforms to it. It can detect common mistakes such as
- you forgot to clear carry before adding something to the accumulator
- a subroutine that you called trashes a register you thought it preserved
- you tried to read or write a byte beyond the end of a byte array
- you tried to write the address of something that was not a routine, to a jump vector
Unlike most languages, in SixtyPical the programmer must manage memory very explicitly, selecting the registers and memory locations to store all data in. So, unlike a C compiler such as cc65, a SixtyPical compiler doesn't need to generate code to handle calling conventions or register allocation. This results in smaller (and thus faster) programs.
The flagship demo, a minigame for the Commodore 64, compiles to
The reference implementation can analyze and compile SixtyPical programs to 6502 machine code formats which can run on several 6502-based 8-bit architectures:
For example programs for each of these, see eg/README.md.
SixtyPical is defined by a specification document, a set of test cases, and a reference implementation written in Python.
- Design Goals
- SixtyPical specification
- SixtyPical revision history
- Literate test suite for SixtyPical syntax
- Literate test suite for SixtyPical analysis
- Literate test suite for SixtyPical compilation
- Literate test suite for SixtyPical fallthru optimization
- 6502 Opcodes used/not used in SixtyPical
- Output formats supported by
git clone https://git.catseye.tc/SixtyPical/
- Remove the "local" loadngo script from here as well. Chris Pressey 3 years ago
- Declare that --run replaces loadngo.sh, and remove the latter. Chris Pressey 3 years ago
- First cut at a --run option for sixtypical, replacing loadngo.sh. Chris Pressey 3 years ago
- The VICE emulators just keep going if they can't find the vicerc. Chris Pressey 3 years ago
- A few further small edits to README. Chris Pressey 3 years ago
- You could argue that it's not *that* low level, so, okay. Chris Pressey 3 years ago
- More edits to docs. Chris Pressey 3 years ago
- Clean up ArgumentParser usage message, add --version argument. Chris Pressey 3 years ago
- Update docs. Chris Pressey 3 years ago
- The Type and Ref class hierarchies are now namedtuples. Chris Pressey 3 years ago