randomizer.c

介绍关于WiMax（IEEE802.16）物理层调制解调编码等相关设计实现

/*****************************************************************************/
/*   FIle Name : randomizer.c                                                */
/*   Description : WiMax FEC randomizer for Encoder/Decoder                  */
/*                 S(x) = x^15 + x^14 + 1 ;                                  */
/*   author : miffie                                                         */
/*   Date   : sep/23/05                                                      */
/*   Copyright (c) 2005 miffie   All rights reserved.                        */
/*****************************************************************************/
struct binaryset randomizer (struct binaryset datain , short *shifter) {
//static short seed = 0x00a9 ;
int 	ii ;
char 	tmp1, tmp2 ;
char	*p ;

  //Main 
    PRINTF("randomizer size=0x%x seed=%x\n", datain.size, *shifter) ;   
    p = datain.data ;
    for(ii=0;ii<datain.size;ii++) { //for
	tmp1 = (*shifter &0x4000) >> 14 ; 
	tmp1 ^= (*shifter &0x2000) >> 13 ; 
        *shifter = (*shifter<<1) + tmp1 ;
        *p++ ^= tmp1 ;
    } //for
    return ( datain ) ;
} //randomizer