Learning assembly [closed]

Answer 1

My personal favorite is NASM, mostly because it's multi-platform, and it compiles MMX, SSE, 64-bit...

I started compiling some simple C source file with gcc, and "trans-coding" the assembler instruction from gcc-format into NASM-format. Then you can change small portions of code, and verify the performance improvement it brings.

The NASM documentation is really complete, I never needed to search for information from books, or other sources.

Answer 2

Knowing assembly can be useful for debugging but I wouldn't get too excited about using it for optimizing your code. Modern compilers are usually much better at optimizing that a human these days.

Answer 3

Some links you might find useful to learn the assembly - source code mapping -

Assembly And The Art Of Debugging

Debugging – Modifying Code At Runtime

Hope you find these useful.

Answer 4

I found Hacking: The Art of Exploitation to be an interesting and useful way into this topic... can't say that I have ever used the knowledge directly, but that's really not why I read it. It gives you a much richer appreciation of the instructions that your code compiles to, which has occasionally been useful in understanding subtler bugs.

Don't be put off by the title. Most of the first part of the book is "Hacking" in the Eric Raymond sense of the word: creative, surprising, almost sneaky ways to solve tough problems. I (and maybe you) was a lot less interested in the security aspects.

Answer 5

To do what you're wanting to do, I just took the Intel Instruction Set Reference (might not be the exact one I used, but it looks sufficient) and some simple programs I wrote in Visual Studio and started throwing them into IDAPro/Windbg. When I out-grew my own programs, the software at crackmes was helpful.

I'm assuming that you have some basic understanding of how programs execute on Windows. But really, for reading assembly, there's only a few instructions to learn and a few flavors of those instructions (e.g., there's a jump instruction, jump has a few flavors like jump-if-equal, jump-if-ecx-is-zero, etc). Once you learn the basic instructions it's pretty simple to get the gist of the program execution. IDA's graph view helps, and if you're tracing the program with Windbg, it's pretty simple to figure out what the instructions are doing if you're not sure.

After a bit of playing like that, I bought Hacker Disassembly Uncovered. Generally, I stay away from books with the word "Hacker" in the title, but I really liked how this one went really in-depth about how compiled code looked disassembled. He also goes into compiler optimizations and some efficiency stuff that was interesting.

It all really depends on how deeply you want to be able to understand the program, too. If you're reverse engineering a target looking for vulnerabilities, if you're writing exploit code, or analyzing packed malware for capabilities, you'll need more of a ramp-up time to really get things going (especially for the more advanced malware). On the other hand, if you just want to be able to change your character's level on your favorite video game, you should be doing fine in a relatively short amount of time.