Neolithic
Neolithic 6502 Cross-Compiler
The Neolithic Compiler is cross-compiler that targets the 6502. The Neolithic language is very similar to C. It's been simplified to help with generating optimal 6502 assembly code.
Disclaimer for Alpha release:
The compiler and language itself are currently in active development and are subject to change at any time. While some things may work perfectly fine in one version, they could potentially be changed/removed in the future. Please keep this in mind when writing code targeting this compiler.
Quick Intro
This compiler supports many C-like constructs including variables, functions, structures, unions, and enumerations. Most of the basic expression and assignment syntax falls in-line with how C works, albeit, simplified. Even the basic structured code elements such as IF, WHILE, DO, and FOR statements generally work the same.
So, what are the differences?
Well, in general, the language has been simplified. Primitive types have been reduced to just 8-bit chars, 16-bit ints, booleans, and pointers. Arrays are one-dimensional.
User-defined types still exist, but only consist of structs, unions, and enumerations; general typedefs have been eliminated. This has been done to simplify code generation. Structs and unions have been "promoted" to being the primary ways of defining new types. In Neolithic, they are handled as typedefs without the need to use the C keyword "typedef".
Another minor difference is that semicolons are optional. They can still be used, but for the most part, they are not necessary. In fact, I have yet to come upon a case in which they are needed. Though I do believe someone might still stumble upon a place where semicolons will be needed.
Limitations
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Currently there is minimal 16-bit support, enough to support pointers, but not enough to handle much of anything else.
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There really is no type checking at this point.
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Syntax is still in flux.
Directory Structure
- /bin - compiler binaries from latest release
- /codegen - generators for code, variable allocation, call tree, symbols, and the evaulator
- /common - common code used in thru-out the code base
- /cpu_arch - instruction generation for the 6502
- /data - commonly used data structures: identifiers, cpu instructions, symbols, labels, syntax tree, types, function map, bank layout
- /docs - documentation and notes
- /examples - example code (to be added)
- /machine - code for dealing with different machine architectures
- /optimizer - some initial optimizer code (currently unused?)
- /output - output module used to generate binary and DASM-compatible assembly output
- /parser - tokenizer + parser for the language
- /test - example programs to test different area of the compiler
Building from Source
This project was developed using the MinGW/GCC compiler and CMake as the primary build system for this project. This is due to this project being developed using JetBrain's Clion IDE.
I'm not opposed to including regular Makefiles as long as someone else takes responsibility for creating and maintaining them.
For more information, please read 'Neolithic Language Guide' in the /docs/ directory.
The book "The C Programming Language: Second Edition" by Brian W. Kernighan and Dennis M. Ritchie was used as a reference for the design of this language.