question about the heap_size

[lyk]

Hello:

     I have a question about the heap_size of MPC5744P:

     I set the heap_size as below:

    __HEAP_SIZE            = 1024

    when I apply for 2048 Bytes, it success;

      uint8_t * p =(uint8_t*) malloc(2048);

    when I apply for space less than 1024, it success;

    when I apply for 4096 Bytes, failed;

     I want to know the reason, thanks!