WebAssembly instructions perform the actual computation. Instructions comprise the body of a function and, in a sense, form the actual program. They are a set of low-level commands that tell the stack machine (WebAssembly's virtual machine) what to do. Each instruction in WebAssembly represents an operation on the abstract machine's stack.

To see how they relate to WebAssembly, let's consider a simple example in C++. Suppose we have an application that aggregates data and provides insights into marketing campaign performance. You have two variables a and b, where a = 42 and b = 28, and you are adding both integers.

1#include <iostream>
2using namespace std;
3
4int main() {
5  // WebAssembly instruction equivalent
6  // i32.const 42
7  int a = 42;
8
9  // WebAssembly instruction equivalent
10  // i32.const 28
11  int b = 28;
12
13  // WebAssembly instruction equivalent
14  // i32.add
15  int c = a + b;
16
17  cout << "The result is: " << c << endl;
18
19  return 0;
20}

In this C++ code, we have three corresponding WebAssembly instructions:

• i32.const 42, setting the integer value of 42
• i32.const 28, setting the integer value of 28
• i32.add, adding two integer constants

One of the exciting things about WebAssembly's instructions is that they operate in a similar way to assembly language, while still being safe and efficient for execution in the web browser.

Understanding WebAssembly instructions provides a foundation to realize that an oftentimes complex marketing campaign performance assessment tool can be converted into a simpler, faster module using WebAssembly.

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#include <iostream>

​

using namespace std;

​

int main() {

  // WebAssembly instruction equivalent

  // i32.const 42

  int a = 42;

​

  // WebAssembly instruction equivalent

  // i32.const 28

  int b = 28;

​

  // WebAssembly instruction equivalent

  // i32.add

  int c = a + b;

​

  cout << "The result is: " << c << endl;

​

  return 0;

}