The execution stack

As seen in the previous chapter, a bare-metal application starts executing with an empty stack area. The execution stack grows backward, from the high address provided at boot to lower addresses every time a new item is stored. The stack keeps track of the chain of function calls at all times by storing the branching point at each function call, but it also serves as temporary storage during function executions. Variables within the local scope of each function are stored inside the stack while the function is executing. For this reason, keeping stack usage under control is one of the most critical tasks while developing an embedded system.

Embedded programming requires us to be aware at all times of stack usage while coding. Placing big objects in the stack, such as communication buffers or long strings, is in general not a good idea, considering that the space for the stack is always very limited. The compiler can be instructed to produce a warning every time...