Project 11.18 Section 11 ⚡ Embedded Relevance: High std::stack LIFO Call Stack Stack Overflow MPU

11.18 std::stack Mechanics, Stack Overflow Hazards, and MPU Guards

Executive Summary: Understanding LIFO stack adapters. We compare data structure stacks with the hardware MCU execution stack, explore stack overflow risks, and examine memory protection unit (MPU) stack watermarking.

💻 1. Annotated Source Code

#include <iostream>
#include <stack>
#include <string>
using namespace std;

void storeReverse(const string& origString, stack<char>& reverseStack);
bool isPalindrome(const string& origString);
void printResult(const string& origString);

int main() {

	string strArray[5] = { "racecar", "fudge", "civic", "bob", "dogs" };

	for (const string& str : strArray) {
		printResult(str);
		cout << endl;
	}

	return 0;
}

void storeReverse(const string& origString, stack<char>& reverseStack) {
	for (char c : origString) {
		reverseStack.push(c);
	}
}

bool isPalindrome(const string& origString) {
	stack<char> reverseStack;
	storeReverse(origString, reverseStack);

	for (char c : origString) {
		if (reverseStack.top() != c) {
			return false;
		}
		reverseStack.pop();
	}

	return true;

}

void printResult(const string& origString) {
	cout << "Is \"" << origString << "\" a palindrome? "
		<< boolalpha << isPalindrome(origString) << endl;
}

📐 2. Architecture & UML Class Model

📐 std::stack Container Adapter (LIFO) Model

+ Public - Private # Protected

<<template class>> std::stack<T, Container> LIFO Adapter

Attributes / Data Members

#c : Container (defaults to std::deque<T>)

Operations / Methods

+push(val: const T&) : void[calls c.push_back]

+pop() : void[calls c.pop_back]

+top() : T&[calls c.back]

+empty() : bool const

+size() : size_t const

📚 3. Core C++ Concepts Deep-Dive

LIFO Stack Operations

std::stack provides push(), pop(), top(), and empty() using LIFO semantics.

⚡ 4. Embedded Systems & Hardware Reality

Hardware Call Stack Constraints

On microcontrollers, stack memory is shared between local variables and interrupt context saving. Stack overflow corrupts global variables silently unless MPU guards are enabled.

💡 5. Production-Ready Embedded Refactoring

💡 Production-Ready Refactor

template <typename T, size_t MaxDepth>
class StaticStack {
public:
    bool push(T val) { if (top_ >= MaxDepth) return false; data_[top_++] = val; return true; }
    T pop() { return data_[--top_]; }
private:
    std::array<T, MaxDepth> data_; size_t top_ = 0;
};

📝 Knowledge Verification Quiz

Test your understanding of the C++ concepts and embedded microcontroller trade-offs covered in this guide. Click any option for instant feedback.

Q1. What is a primary danger of deeply nested recursive functions on microcontrollers?

A Exhausting the fixed MCU hardware call stack and corrupting RAM (Stack Overflow).

B Disabling compiler optimization.

C Destroying flash memory permanently.

D Causing a division by zero.

Detailed Explanation: Microcontrollers have limited stack memory (often 1KB-8KB); recursion risks overflowing into heap/static RAM.