3.5.3. Stack and Program Counter

Try these first

1. 1.

   What does the stack pointer do?

   Hint

   Think about where local data is stored.

2. 2.

   What is the purpose of the program counter?

   Hint

   Consider how the CPU knows what to do next.

3. 3.

   What is the primary role of the stack pointer in the ARM Cortex-M0?

   • A) To execute instructions
   • B) To point to the next instruction
   • C) To manage function call data

   Hint

   Consider what happens to data when a function is executed.

4. 4.

   True or False: The program counter increments by 4 after executing an instruction in a 32-bit architecture.

   • True
   • False

   Hint

   Think about the size of the instructions in memory.

5. 5.

   Design an algorithm using recursion that prints the first n Fibonacci numbers. Explain how the stack pointer and program counter will be manipulated throughout the calls.

   Hint

   Consider the relationship between function parameters and return values.

6. 6.

   Imagine a scenario where an interrupt occurs right in the middle of function execution. Discuss how the processor uses the stack pointer and program counter to handle this event.

   Hint

   Reflect on the importance of saving state for recovery.