Hi8
#define _S_(v16) (Sbox[Lo8(v16)] ^ swap16(Sbox[Hi8(v16)]))
RC4KEY[0] = Hi8(IV16); /* RC4KEY[0..2] is the WEP IV */
RC4KEY[1] =(Hi8(IV16) | 0x20) & 0x7F; /* Help avoid FMS weak keys */