• State Not Answered
  • Locked Locked
  • Replies 8 replies
  • Subscribers 21 subscribers
  • Views 2410 views
  • Users 0 members are here
2025 survey

We are running a survey to help us improve the experience for all of our members. If you see the survey appear, please take the time to tell us about your experience if you can.

Options
Related
How was your experience today?
This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

[51] simulation in KeilC question

shihwen chou

Hi, The test code is listed as below,

#pragma OT(0)
void main (void)
{
    DATA_MSG *b=NULL;
    DATA_MSG *a=NULL;

    b=(DATA_MSG *)malloc(sizeof(DATA_MSG));
    b->sMsgHeader.MessageType=E_Battery_Status;
    b->sMsgHeader.Extended=1;
    //Plug_Status=0;
    //Varible_Init();
    a=(DATA_MSG *)malloc(sizeof(DATA_MSG));
    a->sMsgHeader.MessageType=E_Get_Country_Info;
    a->sMsgHeader.Extended=0;
    if(b->sMsgHeader.Extended || a->sMsgHeader.Extended)
        EX3=1;
    else
        EX3=0;

I use the keil-C simulator to debug it. I found the pointer a and b point to the same memory location.
It means that the a overwrites b, I don't know why? Anyone knows it? Thanks a lot.

Parents
  • 0 in reply to Andy Neil

    Dynamic memory allocation is generally avoided in small embedded systems - like 8051.

    Why do you feel the need for Dynamic memory allocation here?

    the '51 is NOT a PC dynamic memory allocation should be avoided like the plague (MISRA does not allow it)

    I only see mallocs etc when the coder is PC trained and believes the '51 is "just another processor"

Reply
  • 0 in reply to Andy Neil

    Dynamic memory allocation is generally avoided in small embedded systems - like 8051.

    Why do you feel the need for Dynamic memory allocation here?

    the '51 is NOT a PC dynamic memory allocation should be avoided like the plague (MISRA does not allow it)

    I only see mallocs etc when the coder is PC trained and believes the '51 is "just another processor"

Children