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此代码将unsigned long向量变量转换cR1为NB_ERRORS数字（在a变量中我打印这些数字）。

#include <stdio.h>
#include <stdlib.h>
#include <math.h>

int EXT_DEGREE = 8;
int NB_ERRORS = 8;
int BIT_SIZE_OF_LONG = 32;
typedef unsigned short gf_t;
int main(void){

int j, k, l;
gf_t a;
unsigned long cR1 [] = {418636844,2037720909}; //example
for (l = 0; l < NB_ERRORS; ++l) {
    k = (l * EXT_DEGREE) / BIT_SIZE_OF_LONG;
    j = (l * EXT_DEGREE) % BIT_SIZE_OF_LONG;
    a = cR1[k] >> j;
    if(j + EXT_DEGREE > BIT_SIZE_OF_LONG)
        a ^= cR1[k + 1] << (BIT_SIZE_OF_LONG - j);
    a &= ((1 << EXT_DEGREE) - 1);
    printf("a = %d\n", a);
}

例如，我有一个 cR1 数组，其中包含以下两个元素：

0,0,1,1,0,1,0,0,0,0,1,0,0,1,1,1,1,1,0,0,1,1,1,1,0,0,0,1,1,0,0,0 1,0,1,1,0,0,1,0,1,1,1,0,0,1,0,0,1,0,1,0,1,1,1,0,1,0,0,1,1,1,1,0

执行该代码我得到：

    a = 44
    a = 228
    a = 243
    a = 24
    a = 77
    a = 39
    a = 117
    a = 121

这段代码从右到左转换，我想修改为从左到右转换。我可以在哪里修改这个？

4

1 回答 1

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尝试修改j计算线。将其替换为：

j = ( (NB_ERRORS - 1 - l) * EXT_DEGREE) % BIT_SIZE_OF_LONG;

中包含的数字cR1将从左侧开始转换。输出将是：

a = 24
a = 243
a = 228
a = 44
a = 121
a = 117
a = 39
a = 77
于 2016-11-28T15:06:04.957 回答