在XC16 v1.32上有指针的麻烦

大家好，我这里有一个简单的代码。我要读无符号char UART1YRX缓冲器[80 ]，缓冲器从0x9EC开始，它是：在这里我的函数读取缓冲器，在这里我称为WIT-PTR值0x9ED:为什么工作而不是？？？？？？？



      以下为原文

    Hi to all, I have here simple piece of code.

I'm going to read unsigned char UART1_RxBuffer[80], buffer starts at 0x9EC and it is:
0x9EC -> 0x52 (Start header char)

0x9ED -> 0x03 (Header type)
0x9EE -> 0x03 (Number of bytes LSB)
0x9EF -> 0x00 (Number of bytes MSB)
0x9F0 -> 0x01 (message byte 1)
0x9F1 -> 0x00 (message byte 2)
0x9F2 -> 0x00 (message byte 3)
0x9F3 -> 0x04 (checksum LSB)
0x9F4 -> 0x12 (checksum MSB)


Here my function to read buffer where I call wit ptr value 0x9ED:

void ManageHeaderType (unsigned char *ptr)
{
    unsigned char *ptr_chk, *dummy_ptr;
    unsigned char HdrType;
    unsigned int l_NumOfBytes;
    unsigned char CK_A, CK_B = 0;
    unsigned int i, CheckSum;
    unsigned int *int_ptr;
   
    unsigned int brody;
   
    ptr_chk = ptr;
    HdrType = *ptr++; // it correctly reads 0x03
    // reading unsigned int using unsigned char pointer
    l_NumOfBytes = *(unsigned int *)(ptr); // it correctly reads 0x0003
   
    dummy_ptr = ptr;
    dummy_ptr += l_NumOfBytes+2; // ptr value is 0x9F3
   
    int_ptr = (unsigned int *)dummy_ptr; // int_ptr value is 0x9F3, MPLAB X correctly shows *int_ptr = 0x1204 in tooltip
    CheckSum = *(unsigned int *)(dummy_ptr);
    // now CheckSum contents is 0x09F3
    brody = *int_ptr;
    // here value of brody is 0x09F3

Why  l_NumOfBytes = *(unsigned int *)(ptr); works while CheckSum = *(unsigned int *)(dummy_ptr); and brody = *int_ptr; not?????