lz4_bswap16
{ U16 v = A16(p); v = lz4_bswap16(v); d = (s) - v; }
{ U16 v = (U16)(i); v = lz4_bswap16(v); A16(p) = v; p += 2; }
{ U16 v = A16(p); v = lz4_bswap16(v); d = (s) - v; }
{ U16 v = (U16)(i); v = lz4_bswap16(v); A16(p) = v; p += 2; }