A chess move generator written in Zig. Intended for use in high performance chess software, like chess engines.

Priorities, in order:

• Correct
• Fast
• Lightweight
• Simple

Promised features:

• Bitboard-based state representation
• Direct legal move generation (no pseudolegal step)
• Forward-backward move application
• Magic bitboards for sliding piece attacks
• Precomputed attacks for knights and kings
• Zobrist hashing for position repetition detection
• PGN parsing and generation with infinite variation support
• FEN parsing and generation
• UCI move format support
• Comprehensive perft correctness tests
• Comprehensive perft performance tests

Very similar to the bunnies project. Still a work in progress.

The profile build step runs Apple’s Instruments time profiler (xcrun xctrace record --template 'Time Profiler') against the same perft test binary as perft-test, so you never hardcode paths under .zig-cache.

Requirements: macOS with Xcode / command-line tools so xcrun xctrace is available.

Typical usage (release-like optimization):

zig build profile -Doptimize=ReleaseFast

This writes a .trace bundle. By default the path is perft-profile.trace under the install prefix (same place as zig build install / zig build docs: typically zig-out/perft-profile.trace when using the default prefix). The build runs mkdir -p on the trace path’s parent first, so profiling works even when zig-out/ does not exist yet (unlike raw xctrace --output). Open it with Instruments or open zig-out/perft-profile.trace (adjust if you use -p).

Options:

• -Dprofile-trace=path — output path for the trace (default: perft-profile.trace under the install prefix).
• -Dprofile-time-limit=90s — passed to xctrace record --time-limit. Set this longer than the perft run duration; if the limit fires before tests finish, xctrace may exit with a non-zero code even after saving a trace.

On non-macOS hosts, zig build profile fails with a short message so CI does not silently skip profiling.