question about checksum.c

Hi all In the func ipsum_calc_block(u16 *x, unsigned len, u16 sum) ASSERT(!(len % 2)); if (!len) return sum; len >>= 1; if ((unsigned long) x & 2) /* Align to 32-bit boundary, use x's address */ { sum = add16(sum, *x++); len--; } rest = len & 1; len >>= 1; tmp = 0; xx = (u32 *) x; Why do we have two len >>= 1; i understand it will change the xx to move 32 bits one time. Isnt that the first one redundant?