The C language compilation and linking process introduces a set of code that gets linked in called the C-START-UP code. This can be changed by you to your own version of this code provided you know what you are doing. The normal version of the C-START-UP code has the job mainly of setting up the stack pointer and initializing the memory. A standard C environment requires all RAM variable space to be zeroed at start up. There is also a need to initialize any global or static variables that you declared in your C code with an initialized value. These get initialized in RAM or XRAM via a copy from the CODE space. This copy process is also handled by the C-START-UP code. There are various compiler and linker switches and several A51 source files you need to learn about if you want to set about changing the start up behavior. The first place to look is to read the Keil compiler and linker manuals completely through. Then go to the Keil web site and search in their knowledge base. They have much useful online info on this subject at http://www.keil.com.

Michael Karas