Valhalla Legends Archive

Programming => General Programming => Assembly Language (any cpu) => Topic started by: iago on February 19, 2003, 11:24 AM

Title: Offsets [x86]
Post by: iago on February 19, 2003, 11:24 AM
Could somebody please tell me the difference between these two lines:
mov     ecx, dword_19034EEC
mov     ecx, offset dword_19034EEC
Title: Re: Offsets [x86]
Post by: Yoni on February 19, 2003, 11:36 AM
It kind of depends on the assembler/disassembler that you used to get that, but I am guessing that the former copies the contents of dword_19034EEC into ecx, and the latter copies the address of dword_19034EEC into ecx (this address is probably 19034EEC).

If you provided the opcodes as well it would be more obvious.
Title: Re: Offsets [x86]
Post by: Noodlez on February 19, 2003, 11:41 AM
damnit yoni :( i was about to answer that but i went to the bathroom and comeback and your answers here~!

but yea, the first one puts the contents of dword_19034EEC and the second one the address
Title: Re: Offsets [x86]
Post by: iago on February 19, 2003, 11:43 AM
hmm.. IDA doesn't display the opcodes.. *opens w32dasm

:190142A5      mov ecx, dword ptr [19034EEC]
:190142AB      mov ecx, 19034EEC

hmm, guess that just answered my question ;-)
Title: Re: Offsets [x86]
Post by: KaSiaL on February 19, 2003, 01:47 PM
Which version w32dasm u got? I got 8.93. How to make it to switch to another thread in the code window while debugging an app? I need it for WC3 debugging. :( Is IDA better than w32dasm?
Title: Re: Offsets [x86]
Post by: Banana fanna fo fanna on February 19, 2003, 03:23 PM
I never used w32dasm for debugging...but here's my 2 cents.

IDA is way slower than w32dasm...but it has more power. Like, it will try to figure out the C arguments for CALLs, and make a program map and all of that. W32dasm suits my needs better, it's a basic disassembler that meets my needs nicely. Search the net for W32dism++, it adds some nice functionality to W32dasm.
Title: Re: Offsets [x86]
Post by: KaSiaL on February 19, 2003, 04:00 PM
QuoteI never used w32dasm for debugging...but here's my 2 cents.
Thank you ;D
QuoteIDA is way slower than w32dasm...but it has more power. Like, it will try to figure out the C arguments for CALLs, and make a program map and all of that..
Actually my copy o w32dasm tries to figure 'em out, too. 8)
QuoteSearch the net for W32dism++, it adds some nice functionality to W32dasm.
LOL, google returned ony 2 URLs and both are links to some boards. :o
Title: Re: Offsets [x86]
Post by: iago on February 19, 2003, 05:13 PM
IDA is WAAY nicer, it lets you name variables, give functions parameters (that show up as comments before the push's in from the the function), add comments, etc.

For reversing, IDA is much nicer, and it's only slow if you don't save data.  w32dasm is nice because it's so simple, though.

http://www.valhallalegends.com/files/IDA430/ida.zip
Title: Re: Offsets [x86]
Post by: Zorm on February 19, 2003, 05:52 PM
that link requires username/pass iago, mind moving it someplace else so I can grab it?
Title: Re: Offsets [x86]
Post by: Noodlez on February 19, 2003, 07:38 PM
yea, please iago :)
Title: Re: Offsets [x86]
Post by: iago on February 19, 2003, 10:02 PM
It does?  Hmm, I tried it earlier and it didn't, guess somebody didn't want it shared?

Anyway, it will eventually be here:
http://Guest:[email protected]:665/ida.zip
Title: Re: Offsets [x86]
Post by: Arta on February 20, 2003, 06:46 PM
People who know about IDA still use w32dasm?!

IDA is totally superior :)
Title: Re: Offsets [x86]
Post by: iago on February 20, 2003, 09:24 PM
Like everything else, w32dasm has it's place in the world!  I find it cleaner and easier to work with, if I need to look up something, I just open w32dasm and wait the ~30 seconds to disassemble the file instead of opening IDA's saved file and having it done pretty much instantly :)
Title: Re: Offsets [x86]
Post by: Noodlez on February 20, 2003, 10:33 PM
/me pokes iago
gogo put it on your ftp
Title: Re: Offsets [x86]
Post by: Etheran on February 21, 2003, 12:10 AM
I know!! I tried that thin like 5 times now... my ida is shareware..  :'(
C:\Documents and Settings\Daniel Spence>ftp
ftp> o iago.no-ip.com:665
Unknown host iago.no-ip.com:665.
ftp> o iago.no-ip.com 665
Connected to iago.no-ip.com.
220 BulletProof FTP Server ready ...
User (iago.no-ip.com: )none)): Guest
331 Password required for Guest.
Password:
230 User Guest logged in.
ftp> dir
200 Port command successful.
150 Opening data connection for directory list.
it froze after that.. and:
ftp> get ida.zip
200 Port command successful.
550 'ida.zip' : No Such File.
ftp>
Title: Re: Offsets [x86]
Post by: Yoni on February 21, 2003, 02:47 AM
iago (or whoever uploaded that version of IDA to vL.com) owns.

This is THE REAL IDA 4.30, not the crappy "cracked demo" that Acid uploaded a few months ago.
It contains all the FLIRT signatures and supports more than just x86.
Here's a screenshot of it disassembling a .NET EXE:
http://www.valhallalegends.com/yoni/IDADotNET.png

Understandably, the file is password protected to protect vL.com's bandwidth and to prevent it from becoming a l33t warez server.
As soon as I become less lazy (should be around 20-30 minutes from now) I will configure my FTP and put it up on it. Keep in mind though that my upstream is low (12KBps max.) and it's a 30mb file. You'll get over it.
Title: Re: Offsets [x86]
Post by: Yoni on February 21, 2003, 03:15 AM
ftp://[email protected]:43981/ida.zip
(Server: yoni.no-ip.org, port: 43981, username: IDA, no password)

To prevent my bandwidth being raped, I limited access to 1 user at a time.
Title: Re: Offsets [x86]
Post by: Yoni on February 22, 2003, 01:17 AM
Oops... Looking at the logs, it was slightly misconfigured.
You should be able to download more than ~600kb now. :)
Title: Re: Offsets [x86]
Post by: MrRaza on February 22, 2003, 05:09 AM
ugh, slow downloading but thanks  ;D
Title: Re: Offsets [x86]
Post by: iago on February 22, 2003, 09:11 AM
Quoteiago (or whoever uploaded that version of IDA to vL.com) owns.

Yes, I uploaded it, but Arta sent it to me so we're all good.

You can download it from my ftp also, ftp://iago.no-ip.com:665.  Username/Password = Guest.  My max upspeed is ~30kbps and I haven't limited users (There's also other useful stuff on the ftp but IDA is by far the best)
Title: Re: Offsets [x86]
Post by: Yoni on February 22, 2003, 09:38 AM
Nice stuff iago :)
Quoteftp> dir ebooks
200 Port command successful.
550 Permission denied.
ftp> dir Misc
200 Port command successful.
550 Permission denied.
ftp> dir Movies
200 Port command successful.
550 Permission denied.
ftp> dir Music
200 Port command successful.
550 Permission denied.
ftp> dir Pictures
200 Port command successful.
550 Permission denied.
ftp> dir Programs
200 Port command successful.
550 Permission denied.
Title: Re: Offsets [x86]
Post by: iago on February 22, 2003, 11:53 AM
eek, forgot to set +subdirs, will do that now
Title: Re: Offsets [x86]
Post by: iago on February 22, 2003, 11:55 AM
ftp://Guest:[email protected]:665/Programs/ida.zip works, I just tested it.