An earlier article, we have seen C runtime: before starting main & How C program stored in RAM memory. Here we will see "How C program converts into assembly?" and different aspect of its working at machine level. We will focus on a stack frame of the function that is called by call instruction. The direction of stack frame growth totally depends on compiler ABI which is out of our scope for this article. The complete information on stack frame size, memory allocation, returning from stack frame is decided at compile time.