# c65gm

A high-level 6502 cross-compiler targeting the ACME Cross-Assembler. c65gm provides a more expressive language for writing 6502 assembly programs, with features like functions, type-checked variables, control flow structures, and compile-time optimizations.

## What It Does

c65gm compiles high-level source code into ACME assembler syntax for the 6502 processor (Commodore 64 and similar platforms). It provides:

- **Type system**: BYTE and WORD variables with scope resolution
- **Functions**: Named functions with parameters and call graph analysis
- **Control flow**: IF/ENDIF, WHILE/WEND, FOR loops, SWITCH/CASE
- **Memory operations**: PEEK/POKE/PEEKW/POKEW with zero-page optimization. Access registers as variables.
- **Operators**: Arithmetic (ADD, SUB), bitwise (AND, OR, XOR)
- **Preprocessor**: File inclusion, macros, conditional compilation, Starlark scripting
- **Standard library**: C64 screen/kernal routines, memory management, string handling, graphics (Koala), FAT16 filesystem, and more (accessed via `#include <file>`, path set by `C65LIBPATH` environment variable)
- **Optimizations**: Constant folding, self-assignment detection
- **Safety features**: Compile-time detection of overlapping absolute addresses in function call chains

## Requirements

- **Go**: Version 1.25.1 or higher (tested with 1.25.5)
- **Acme**: Tested with release 0.97 ("Zem")


The project uses Go modules with these dependencies:
- `github.com/armon/go-radix` - Prefix tree for command lookup
- `go.starlark.net` - Embedded Starlark scripting support

## Building

Build the compiler binary:

```bash
go build -o c65gm
```

Or install to your GOPATH:

```bash
go install
```

## Usage

Compile a source file to ACME assembly:

```bash
./c65gm -in input.c65 -out output.asm
```

Then assemble the output with ACME:

```bash
acme -f cbm -o output.prg output.asm
```

## Running Tests

Run all tests:

```bash
go test ./...
```

Run tests with verbose output:

```bash
go test -v ./...
```

Run tests for a specific package:

```bash
go test ./internal/compiler
go test ./internal/commands
```

## Examples

See the `examples/` directory for sample programs:
- `hires/` - High-resolution graphics demo
- `multicolorbm/` - Multicolor bitmap demo
- `memlib_demo/` - Memory library usage
- `switch_demo/` - SWITCH/CASE statement examples

## Documentation

- `language.md` - Complete language reference
- `syntax.md` - Syntax guide
- `commands.md` - Command reference

## License

Copyright (C) 1999, 2025 Mattias Hansson
Distributed under GPL.