Index
> Windows > Procedures (string arguments, arguments addressing) |
| Author |
|
|
LocoDelAssembly 18 Jun 2007, 17:42
Here is the documentation about Win32 Headers http://flatassembler.net/docs.php?article=win32 (includes proc explanation).
Your problem is that you must use stdcall instead. With invoke the first parameter is the address of a pointer to proc while with stdcall, the first parameter is the address of the proc. Code: ; invoke xer, nopatch, patch push patch push nopatch call dword [xer] ; stdcall xer, nopatch, patch push patch push nopatch call xer Above is the difference between using invoke and stdcall for your particular procedure. About addressing parameters it is explaned in the documentation |
|||
18 Jun 2007, 17:42 |
|
|
jumpex 20 Jun 2007, 13:31
Thank you for your responce. Is there a way to use the 'invoke' method? Also I have another problem.
Procedure: Code: proc xer,repla:WORD,subst:WORD locals key db "SOFTWARE\Skype\Phone",0 value db "SkypePath",0 path dd 256 dup(?),0 skyhand dd ? endl invoke RegOpenKeyEx,HKEY_LOCAL_MACHINE,key,0,KEY_READ,skyhand endp Error: Quote: Invalid value. (pushd ...var?000068F) On line with the RegOpenKeyEx function. When I declare the variables outside the procedure in the program, where I'm calling it, all works fine. What is the problem with the local variable? (key or skyhand are the problem, I guess) |
|||
|
20 Jun 2007, 13:31 |
|
|
LocoDelAssembly 20 Jun 2007, 15:27
You don't really read the documentation, don't you?
The problem is that you are referencing variables in stack space which has no absolute offset but EBP-relative offset. To pass the offset of such variables you have to use "addr var" (again read documentation). BTW, note that initializing vars in locals generates code that loads them in run-time everytime you call the procedure. I suggest this code Code: proc xer,repla:WORD,subst:WORD locals path dd 256 dup(?),0 ; do you really need the ending zero and 1024 bytes for a path? skyhand dd ? endl invoke RegOpenKeyEx,HKEY_LOCAL_MACHINE, .key,0,KEY_READ, addr skyhand .key db "SOFTWARE\Skype\Phone",0 .value db "SkypePath",0 endp |
|||
|
20 Jun 2007, 15:27 |
|
|
jumpex 20 Jun 2007, 15:45
The only things I found about procedures and local variables in them in the documentation were very few and didn't give me an answer. Could you quote where should I look?
Moreover - i tried with 'addr ', but that didn't work. The same error appears. Nothing different. As if 'addr ' wasn't there. I'd be HAPPY to read the part of the documentation you give me if I will find an answer there. I'm not lazy. Before I decide to post here, I look in GOOGLE, in my books about assembly, in FASM.PDF, in the documentation here, at flatassembler,net and the message board. Never thought that I couldn't find what I was looking for if it was there. But maybe it's my mistake. So, again, could you Quote the place, where procedures are covered in detail? Thank you. |
|||
|
20 Jun 2007, 15:45 |
|
|
LocoDelAssembly 20 Jun 2007, 16:03
http://flatassembler.net/docs.php?article=win32
Quote: 2.1 Procedure parameters In "1.3 Procedures" you have the documentation about procedures and talks about stdcall and invoke. To use addr you have to include the extended headers (win32{a|w}x.inc). See "2. Extended headers" also. I think the documentation covers more or less all one needs to code with those headers but if something is missing ask. |
|||
|
20 Jun 2007, 16:03 |
|
|
jumpex 20 Jun 2007, 16:16
Hey... thank you for pointing that out, I've read it. This was what I was missing:
Quote:
I'm sorry if I sounded rude, but I really try not to seek help. I read that part of the documentation so many times and tried with the addr in every single way. The tip (about variables and run-time) is also very helpful. Really grateful. Sorry again. And thank you. P.S: Works. I'll search even harder from now on. |
|||
|
20 Jun 2007, 16:16 |
|
|
r22 20 Jun 2007, 16:25
As an aside to this RTFM thread what is everyones view about local variables ?
For PROCs that are NOT thread-safe or recursive (HLL equiv of PUBLIC STATIC/FINAL) I tend to define local variables in my .data section. PROs: No stack based addressing, reusable global TEMP variable CONs: Possible source maintainability issues I don't use the PROC macro NOT because of some bloated sense of preserving the natural flow of assembly, but because I don't think it's all that useful. |
|||
|
20 Jun 2007, 16:25 |
|
|
LocoDelAssembly 20 Jun 2007, 17:37
Quote: PROs: No stack based addressing, reusable global TEMP variable OK, you're not wasting time in creating a stack frame but you are using absolute addressing which makes instructions longer and hence preventing the CPU of decoding more instructions on some situations. Apart of that: 2. Optimizing subroutines in assembly language
An optimization guide for x86 platforms By Agner Fog. wrote: 4.2 Data storage The reusability of TEMP var you mention as a PRO doesn't add anything to the stack based method since it always reuse stack space and automatically. Anyway, I agree that it's not required to use PROC macro for every procedure you have, someones are better to implement with ESP based frame and these headers doesn't support it and sometimes a register based arguments passing is better than the stack based one. |
|||
|
20 Jun 2007, 17:37 |
|
|
r22 21 Jun 2007, 00:03
Loco, the reusability was on the programming side, if your making a lot of PROCs it's slightly more convenient then allocating a local in each PROC; that PRO was definetly subjective.
But after some benchmarking the Global Vs Local temp var speeds vary a lot (sometimes local is faster sometimes global) but on average the local is faster. With arrays the local version is much faster. Although you can't make a very large array using the stack. Guess I'll have to change my bad habit  |
|||
|
21 Jun 2007, 00:03 |
|
< Last Thread | Next Thread > |
Forum Rules:
|