scrambler.c

This model is just testing an idea of MIMO, which IEEE802.11n will have. But I havo not seen the s

/*****************************************************************************/
/*   FIle Name : scrambler.c                                                 */
/*   Description : WLAN FEC scrambler for Encoder/Decoder                    */
/*                 S(x) = x^7 + x^4 + 1 ;                                    */
/*   author : miffie                                                         */
/*   Date   : aug/04/05                                                      */
/*   Copyright (c) 2005 miffie   All rights reserved.                        */
/*****************************************************************************/
struct binaryset scrambler (struct binaryset datain, char seed) {
int 	ii ;
char 	shifter ;
char 	tmp1, tmp2 ;
char	*p ;

  //Main 
    shifter = seed ;
    p = datain.data ;
    for(ii=0;ii<datain.size;ii++) { //for
	tmp1 = (shifter &0x40) >> 6 ; 
	tmp1 ^= (shifter &0x08) >> 3 ; 
        shifter = (shifter<<1) + tmp1 ;
        *p++ ^= tmp1 ;
    } //for
    return ( datain ) ;
} //scrambler