nx_crc32.nx

nx_crc32.nx -- CRC-32 (IEEE 802.3, gzip / zlib / png polynomial). Used for: gzip integrity, png chunk checksums, ELF .gnu.hash table consistency, network protocol framing checks. We use the standard reflected polynomial (0xEDB88320), seed 0xFFFFFFFF, and final XOR 0xFFFFFFFF. Matches: - zlib crc32() - python binascii.crc32() - tar/gzip/png/ethernet checksums The 256-entry lookup table approach is the textbook method -- 8 bits of input per iteration, ~1 GB/s on a modern CPU. We build the table at runtime (no static initialisers in NishiLang yet) and cache it in BSS so subsequent calls are O(n). Slice-by-N (faster) is deferred until we benchmark a real bottleneck.