1.4 KiB
lec13
Let's break down what most/any program must have(executable):
Data
We need a place to put variables and maybe some compile time constants so when we compile our program we can place those things here.
Code
This section will contain all of our running code(duh it's in the name). If you write any functions, loops etc they will live here.
Stack
This area is used heavily for functions. Any time we call a function we push a return address onto our stack for instance so that we know where to go back to when that function ends.
Little Endian & Big Endian
Let's say we have the number 5431.
Since the 5 is the largest number here we'll say this number is in big endian format but if we wrote backwards... we have 1345 we would say it's stored as little endian because 1 is the smallest number but its at the front.
For hex we do something very similar: take 0x45FA as big endian.
Converting 0x45FA to little endian we get 0xFA45
??Wait that does seem right!?!
Here's the one caveat: bytes aren't affected by little or big endianess. So just leave the bytes alone and reverse them from there.
Significance of this
The reason why we care is because if you're going to be writing assembly code then you must understand these things to successfully create anything with assembly. Even so this will give a deeper understanding of what goes on when something happens in your code.