Galois字段算法从C到Matlab

Question

我正在从Gallois字段乘以2来转录Matlab的C代码，问题是我的matlab代码没有显示与C代码相同的值。显然一切正常，我评论了matlab中的代码来识别代码下方C代码的改编。

C：

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

int main() 
{ 
    unsigned char value = 0xaa; 
    signed char temp; 
    // cast to signed value 
    temp = (signed char) value; 
    printf("\n%d",temp); 
    // if MSB is 1, then this will signed extend and fill the temp variable with 1's 
    temp = temp >> 7; 
    printf("\n%d",temp); 
    // AND with the reduction variable 
    temp = temp & 0x1b; 
    printf("\n%d",temp); 
    // finally shift and reduce the value 
    printf("\n%d",((value << 1)^temp)); 
} 

输出：

-86 
-1 
27 
335 

MatLab的：

hex = uint8(hex2dec('1B'));      % define 0x1b 
temp = uint8(hex2dec('AA'));     % temp = (signed char) value; 
disp(temp); 
value = uint8(hex2dec('AA'));     % unsigned char value = 0xaa 
temp = bitsra(temp,7);       % temp = temp >> 7; 
disp(temp); 
temp = bitand(temp,hex);      % temp = temp and 0x1b 
disp(temp); 
galois_value = bitxor(bitsll(value,1),temp); % ((value << 1)^temp) 
disp(galois_value);        % printf ("\n%u",...)      

输出：

170 

    1 

    1 

    85 

C代码正常工作，我在C代码中打印%d以显示变量的整数值，因为在代码的开始时强制转换。

有人知道发生了什么

Answer 1

试试这个：

hex = uint8(hex2dec('1B')); 

temp = typecast(uint8(hex2dec('AA')), 'int8'); 
disp(temp); 

temp = bitshift(temp,-7); 
disp(temp); 

temp = bitand(typecast(temp,'uint8'),hex); 
disp(temp); 

galois_value = bitxor(bitshift(uint16(hex2dec('AA')),1),uint16(temp)); 
disp(galois_value);