gcc6809-nix

Nix flake for building a GCC 4.3.6 cross-compiler targeting the Motorola 6809 CPU on macOS ARM64 (Apple Silicon).

Nix package manager with flakes enabled. If you're new to Nix on macOS, see Setting up Nix on macOS for installation and setup.

# Build the toolchain
nix build

# Enter a shell with the toolchain available
nix develop

# Compile a test program
echo 'int main() { return 42; }' > test.c
m6809-unknown-none-gcc -S test.c -o test.s

• m6809-unknown-none-gcc - GCC 4.3.6 cross-compiler
• as6809 - ASxxxx assembler
• aslink - ASxxxx linker
• libc.a - Newlib C library

cd example
nix develop ..
m6809-unknown-none-gcc -Os -S $M6809_CFLAGS hello.c -o hello.s
as6809 -o hello.s
aslink -s -m -w -o hello.s19 -b .text=0x2000 hello.rel -l $M6809_LIBC

nix develop -c uv run tests/run_tests.py

Runs 18 test cases covering basic operations, 32-bit arithmetic, and regression tests for fixed compiler bugs.

This build includes fixes for several m6809 backend bugs. See patches/README.md for details:

• arm64-darwin.patch - Fixes for building GCC 4.3.6 on Apple Silicon
• indirect-call-fix.patch - Fixes indirect function calls after setjmp
• mulsi3-fix.patch - Fixes 32-bit multiplication returning 0

Currently only supports aarch64-darwin (Apple Silicon Macs) due to ARM64-specific patches required to build GCC 4.3.6.

• GCC: GPL-3.0-or-later
• Newlib: BSD-3-Clause
• Patches in this repo: Same license as the code they patch