What’s going on here is really something quite amazing. Let me sum it up. The author makes a C program that consists of one line of code.
/* tiny.c */
int main(void) { return 42; }
The result is an application size of 3998 bytes.
He then proceeds to write the same thing in ASM; reducing the size over and over until he results with an astonishing 45 bytes! This is my inspiration for becoming a future Systems Engineer.