Comments for endeavormac

Comment on Making Perfect Rainbow Tables Faster by Mike

Mike — Fri, 23 Apr 2010 20:23:31 +0000

Can you contact me? I’m currently using project-rainbowcrack’s rtgen to build a large number of rainbow tables for later perfection. Having a tool such as yours would be immensely helpful.

Comment on x86 Assembly for C Programmers 1 by endeavormac

endeavormac — Tue, 13 Apr 2010 17:14:14 +0000

BX is simply the 16 least significant bits of the EBX register. Actually, I’m not entirely sure if it’s the least or most significant bits. In any case, you can use BX to access the 16 (most|least) significant bits of the EBX register (assuming a current 32bit intel CPU).

This url may provide some enlightenment: http://www.arl.wustl.edu/~lockwood/class/cs306/books/artofasm/Chapter_4/CH04-1.html#HEADING1-42

A short is 16 bits, so make sure your printf string is adjusted (You’ll need %h) http://www.opengroup.org/onlinepubs/000095399/functions/printf.html

So if you want to print out BX, you’ll need to push BX onto the stack, followed by a pointer to a string “%h”, and then call printf. Because BX is only 16 bits and, assuming a 32 bit platform, you’re pushing BX onto a 32 bit word, you may want to mov a 0×0 into that stack space first, or otherwise insure that it is empty, to account for whatever may already be in place of the other 16 bits. I’m not positive that would be necessary, you would have to experiment.

You may have better luck creating a simple C app that does all this and then “gcc source.c -S” to see what you get.

Comment on x86 Assembly for C Programmers 1 by Min

Min — Tue, 06 Apr 2010 07:32:37 +0000

is there a way to make the output 16 bit instead of 32 bit? For example i want bx instead of ebx

Comment on x86 Assembly for C Programmers 1.1, Reddit Follow-up by nobody

nobody — Wed, 18 Nov 2009 08:21:19 +0000

Here's a very similar to yours but much more complete tutorial in russian. Don't you know russian by chance? It would be great if it would be traslated to english! link

Comment on x86 Assembly for C Programmers 1.1, Reddit Follow-up by endeavormac

endeavormac — Sun, 08 Nov 2009 16:10:07 +0000

I’m glad you found it useful. I’ve started on part 2, but other things have gotten into the way of me finishing it.

Comment on x86 Assembly for C Programmers 1.1, Reddit Follow-up by Tom

Tom — Sun, 08 Nov 2009 06:54:33 +0000

Just wanted to thank you for your tutorial. I found myself staring at assembly and forgetting all I had ever learned about it, and you helped me immensely. I was even able to make a blog post about it http://ritter.vg/n.php?page=code_adventures_clr2

Comment on x86 Assembly for C Programmers 1 by inter

inter — Thu, 29 Oct 2009 22:49:53 +0000

gcc -O0 -g -c one.c
objdump -C -M intel -S one.o

This gives an even better result (asm code with source code side by side).

Comment on x86 Assembly for C Programmers 1 by endeavormac

endeavormac — Fri, 23 Oct 2009 21:13:23 +0000

I didn’t know about this feature for gcc, and this is awesome. Thanks!

Comment on x86 Assembly for C Programmers 1 by jldugger

jldugger — Fri, 23 Oct 2009 20:54:33 +0000

gcc -S -masm=intel -o one.asm one.c

For writing your own code, use the compiler instead of the object analyzer. You get jump targets, which is damn handy.

Also stack alignment has more to do with processor design than memory segmentation.

Comment on x86 Assembly for C Programmers 1 by drill

drill — Fri, 23 Oct 2009 19:27:48 +0000

Two requests:

1) Give this series its own special tag on your blog so it’s easy to access the whole thing when you’re done

2) some ideas of simple projects a beginner could do that are actually doable
a) in assembly
b) by someone with the knowledge level this is aimed at.

I’m bookmarking your site.