The executable file you see is Microsofts PE (Portable Executable) format. It's all kind of difficult to explain all at once, but the resources I've provided should help cure at least some of your curiosity! :) the first executable instruction) is usually found at the same place within the EXE file. Most of it is applicable even to modern day consumer Intel CPUs. Paul Carter's PC Assembly Language Tutorial which is a free entry level book that talks about assembly and how the Intel 386 CPU operates. In reality, there are many different 'mov' instructions, ones for handling 8-bit, 16-bit, 32-bit data, ones for moving data from different registers and so on. Some instructions are generalised, like 'mov' which tells the CPU to move data from a CPU register to a place in memory, or vice versa. It mostly depends on the kind of data that the instruction expects. Generally speaking, CPU instructions are of variable length, some are one byte, others are two, some three, some four etc. It also tells you what API functions the program uses and if possible, the arguments that it provides (as long as the arguments are found on the stack). OllyDbg is an awesome tool that disassembles an EXE into readable instructions and allows you to execute the instructions one-by-one. How can I understand what goes on inside an EXE file? But this does not necessarily have to be a SWF slideshow, ACD See is also capable of producing EXEcutable presentations. exe written? Four bytes per instruction? More? Less? I have noticed some applications can create executable files just like that: for example, in ACD See you can export a series of images into a slideshow. Is there any straightforward way of reading the machine code? Opening the exe as a file stream and reading it byte by byte, how could one turn these individual bytes into Assembly? Is there a straightforward mapping between these instruction bytes and the Assembly instruction? I suppose the unreadable part (majority) is the machine code (or maybe resources, such as images etc.). When I open these files up in a specialized viewer, I can find strings (usually 16b per character) scattered at various places, but the rest is just garbage. I will narrow down the subject of this question to Win32 executables (.exe). The act of transforming human-readable code (or the not really readable Assembly instructions) into machine code is, for me, rocket science combined with sorcery. I am not well acquainted to the compiler magic.

How to read exe code