在opencl中的uchar sqare內核，行爲？

Question

我做了一個內核：

__kernel void square(              
    __global uchar* input,            
    __global uchar* output,           
    const unsigned int count)          
{                  
    int i = get_global_id(0);           
    if(i < count)              
     output[i] = input[i] * input[i];         
}; 

從我的程序的輸出，輸入矩陣和輸出中。我發現所有工作項目的評估結果都是val * val％256。爲什麼？

Found 1 platform(s). 
OutData from Write and Read: 
0 
[91, 2, 79, 179, 52, 205, 236, 8; 
    181, 239, 26, 248, 207, 218, 45, 183; 
    158, 101, 102, 18, 118, 68, 210, 139; 
    198, 207, 211, 181, 162, 197, 191, 196; 
    40, 7, 243, 230, 45, 6, 48, 173; 
    242, 125, 175, 90, 63, 90, 22, 112; 
    221, 167, 224, 113, 208, 123, 214, 35; 
    229, 6, 143, 138, 98, 81, 118, 187; 
    167, 140, 218, 178, 23, 43, 133, 154; 
    150, 76, 101, 8, 38, 238, 84, 47] 
[89, 4, 97, 41, 144, 41, 144, 64; 
    249, 33, 164, 64, 97, 164, 233, 209; 
    132, 217, 164, 68, 100, 16, 68, 121; 
    36, 97, 233, 249, 132, 153, 129, 16; 
    64, 49, 169, 164, 233, 36, 0, 233; 
    196, 9, 161, 164, 129, 164, 228, 0; 
    201, 241, 0, 225, 0, 25, 228, 201; 
    217, 36, 225, 100, 132, 161, 100, 153; 
    241, 144, 164, 196, 17, 57, 25, 164; 
    228, 144, 217, 64, 164, 68, 144, 161] 


OutData from Write and Read: 
8913 
Succed 
Press any key to continue . . . 

Answer 1

答案是操作在GPU上溢出，當使用uchar類型時，256再次變爲0，循環繼續。