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<gr00ber> i want to update a pointer argument:
<gr00ber> void setESP(int** esp);
<gr00ber> which I wanna call with:
<gr00ber> int* esp;
<gr00ber> setESP(&esp);
<gr00ber> this asm seems to be flawed:
<Robert> Why a double pointer?
<gr00ber> setESP:
<gr00ber> mov eax,[ebp+4]
<gr00ber> mov [eax], esp
<gr00ber> ret
<gr00ber> Robert, dunno. That's how the linux code does it :-) To get the esp value into a pointer.
<gr00ber> don't understand that code, though
<Robert> Well.. if you REALLY want the C function to behave like that, do this:
<Robert> setESP:
<Robert> mov eax,[esp+4] ; not ebp! You have no stack frame here
<Robert> mov eax,[eax]
<Robert> mov [eax],esp
<Robert> ret
<Robert> I just can't see why you want this.
<gr00ber> I have no idea either.
<gr00ber> thanks.
<aFlag> me neither
<Robert> Heh.
<Robert> "I don't know why I want this".
<gr00ber> yup
<aFlag> i think he's reading linux code
<aFlag> and trying to understand
<gr00ber> yup
<gr00ber> nope
<gr00ber> trying to rip of stuff without understanding :-)
<aFlag> then he's just reading it
<aFlag> hehe
<gr00ber> lazy f**k
<aFlag> why do you want to rip of stuff?
<gr00ber> dunno
<aFlag> are you writting your own kernel?
<gr00ber> just playing around
<gr00ber> me writing a kernel is like George Bush writing a book
<gr00ber> result => a piece of crap
<aFlag> i bet you can write a decent one if you put some effort
<gr00ber> some effort? that's the understatment of the century, isn't it?
<Robert> No.
<aFlag> it's not that hard writting a kernel, the hard part is all the functionalities you have to write due to all the different stuff computers do
<gr00ber> depends on the kernel sofistication i guess
<Robert> If I were you, I'd write a simple kernel for a simple computer.
<Robert> The PC is not simple.
<gr00ber> the linux kernel is a major undertaking because of all the micro optimizations
<Robert> Linux is not simple.
<Robert> You want to avoid these.
<aFlag> like, you have to write stuff for handling video input, firewire, all that kinda stuff
<gr00ber> Robert, HA - your solution worked
<gr00ber> nice
<aFlag> getting threads and a good virtual memory system will require some work
<gr00ber> video input?
<aFlag> but that's not necessarily the kernel
<aFlag> you could have most of it outside the kernel
<Robert> gr00ber: It's just that this is a very odd way of doing something this simple.
<Trinsic> linux is slow compared to windows.
<Robert> gr00ber: Normally you'd just inline mov [variable],esp
<gr00ber> well, i guess it's for a reason
<Trinsic> though it's more stable.
<aFlag> gr00ber, yeah, like that video for linux thing on linux
<Robert> Linux is slow?
<Robert> Strange.
<gr00ber> lol
<Robert> I never noticed that.
<Robert> Trinsic can't be wrong - only my eyes.
<aFlag> linux is fairly fast
<gr00ber> I'm writing this on Linux on an 8 year old computer and it flies
<Trinsic> ake about 4 minutes to boot. windows xp takes about 35 seconds.
<Trinsic> takes
<gr00ber> Trinsic, ???
<Robert> Trinsic: Depends how much you load.
<aFlag> i think it even beats the bsds in the benchmarks
<gr00ber> I boot in less than a minute on this old crap computer
<Robert> Yes, same here.
<gr00ber> the 2.6 kernel rox
<Trinsic> applications are faster too.
<Robert> Do you have any case of support for that claim?
<Robert> (other than microsoft-sponsored benchmarks)
<Robert> any kind of*
<aFlag> Trinsic, you are probably loading tons of stuff you don't use
<Trinsic> do not trust and you will not be trusted.
<aFlag> or that you don't even have hardware for
<Trinsic> possibly.
<Trinsic> i am using standard suse.
<Robert> Hah.
<aFlag> there you go
<Robert> I removed SuSE on the box of a guy.
<Robert> Installed the default install in Debian.
<Robert> MUCH faster.
<aFlag> i like debian
<aFlag> i use it :)
<Robert> Even though Debian isn't _that_ minimalist, really.
<Robert> It's just infinitly much better than SuSE>
<aFlag> well, if you take out discover and compile your own kernel the load time will be as fast as you can get
<aFlag> but i don't because i'm lazy hehe
<Trinsic> an example is i should be loading postfix, becuase i never use it.
<Trinsic> shouldn't
<aFlag> and because i don't understand lots of stuff in the kernel's menu thing
<gr00ber> Huh.
<gr00ber> Does General Protection Fault, error code 10108 mean anything to you?
<skuggi> 10108 sorta look like a winsock error code :P
<gr00ber> lol
<gr00ber> well, with the new fancy intel chip sets with WLAN built in, who know what error codes will pop up
<skuggi> mm jag 3 full
<skuggi> *hick
<iojkl> hello
<joshux> are there any good dos programming tutorial ?
<xark> joshux: Sure lots. Probably more than 32-bit x86 programming.
<aegray> i **** at conditionals
<aegray> if i have rsbs r12, r0, r1 lsr #8; bcc addr
<aegray> thats: r12 = (r1 >> 8) - r0;
<aegray> but when would the carry flag be set?
<aegray> if ((r1 >> 8) < r0)?
<xark> Hmm, on ARM carry will be clear if the result is >= 0. I think. :)
<welson> anyone has read 'Art of ***embly' ?
<welson> i'd like to get my feet wet-- in begining reading upon ***embly
<aegray> xark: thanks
<chille> can i mov a dword from one place in memory to another on x86 with just one instruction or do i have to use registers?
<wobster> not with a single but without using the regs. look for LODS ops
<chille> okay
<intero> what is the diffrence between lea and mov?
<dr3f> lea=give you address of something
<dr3f> mov = put data somewhere
<dr3f> if you worked with c,i can say lea is like & and mov is like =
<undesktop> yeah, lea doesn't read the data, it just gives you the address of that data
<Robert> Heh.
<undesktop> so you can use the CPUs address caclulation facitility to do your own stuff
<intero> ah thanks alot everyone!
<Robert> The #asm faq should have three entries: "what's lea?", "how do I print a number?" and "how do I write an operating system without actually having to know what I'm doing?"
<skuggi> :)
<Robert> (note that the first two entries aren't intended to be insulting)
<intero> good that you specified
<Robert> Hehe.
<Robert> It's just that people have been protected from converting string to integers and vice versa.
<Robert> So they can't imagine how to do such a simple thing.
<Robert> And about lea... I guess it's just something different from what people normally do.
<undesktop> maybe people are confused by lea, because you can do the same with add/shr (etc)
<dr3f> they confused because,at some compilers like fasm,you can do mov reg,var
<dr3f> without using "offset" word
<dr3f> and its look the same as lea
<undesktop> oh
<xark> I thought lea was to multiply by 5. :)
<xark> er, was for...
<dr3f> lea dont connected with math
<intero> xark: leal
<xark> intero: Well, that depends on your ***embler
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