Stack probing: Win7 vs WinXP

[jj2007]

Consider this simple program, which calls a proc repeatedly:

Code Select Expand

include \masm32\include\masm32rt.inc ; plain Masm32 for the fans of pure assembler

.code
buffersize=40000
algo proc arg
Local var1, buffer[buffersize]:BYTE, var2
  mov var1, 123
  mov var2, 456
  print str$(esi), 13
  ret
algo endp

start: mov ebx, esp
xor esi, esi
print hex$(ebx), " at start", 13, 10
.Repeat
sub esp, 100
invoke algo, 12345
inc esi
.Until esi>2000
mov esp, ebx
print chr$(10, "ok?", 13, 10)
print hex$(ebx), " at end"
exit
end start

In my tests, the buffersize limits are as follows - beyond these values, you need to implement stack probing:

Code Select Expand

Win7-64 40,400
Win10 20,200
WinXP-32 12,100

In practice, the limit for XP can be below 8,000 bytes, as found out in this thread.

[HSE]

Hi JJ!

Somethings is failing here:

Code Select Expand

include \masm32\include\masm32rt.inc ; plain Masm32 for the fans of pure assembler

.code
unrolles = 20

repeat unrolles
    ifndef topea
        topea = 0
        buffersize = 8000
    else
        topea = topea+1
        buffersize = buffersize+500
    endif
    @CatStr(algo, %topea) proc arg
     %   Local var1, buffer[buffersize]:BYTE, var2
          mov var1, 123
          mov var2, 456
      %   mov buffer [buffersize-1], 1
          mov esi, buffersize
          print str$(esi),@CatStr(<!"  >,algo, %topea,<!">), 13,10
          ret
    @CatStr(algo, %topea) endp
endm

start:
    mov ebx, esp
    xor esi, esi
    print hex$(ebx), " at start", 13, 10
    repeat unrolles
        ifndef topeb
            topeb = 0
        else
            topeb = topeb+1
        endif
        sub esp, 100
        invoke @CatStr(algo, %topeb), 12345
        inc esi
    endm
    mov esp, ebx
    print chr$(10, "ok?", 13, 10)
    print hex$(ebx), " at end",13,10
    inkey
    exit
end start

I expect a crash beyond 12000 (like in your program), but nothing happen.  :redface:

Code Select Expand

0012FF8C at start
8000  algo0
8500  algo1
9000  algo2
9500  algo3
10000  algo4
10500  algo5
11000  algo6
11500  algo7
12000  algo8
12500  algo9
13000  algo10
13500  algo11
14000  algo12
14500  algo13
15000  algo14
15500  algo15
16000  algo16
16500  algo17
17000  algo18
17500  algo19

ok?
0012FF8C at end
Press any key to continue ...

[jj2007]

Nothing happens because, unlike in my example, you are probing the stack. Try buffersize = buffersize+5000

[aw27]

If you link with the following switch, you can continue to produce code like the one that caused the mysterious Windows bug.
/STACK:1048576,1048576

[jj2007]

The only switch that I really need is the one that blocks certain trolls from my threads :P

[HSE]

No problem with 5000, but with 8000 (when 48000)

But I can "easily" obtain a crash reverting the calling order:

Code Select Expand

    repeat unrolles
        ifndef topeb
            ;topeb = 0
            topeb = unrolles-1
        else
            ;topeb = topeb+1
            topeb = topeb-1
        endif
        sub esp, 100
        invoke @CatStr(algo, %topeb), 12345
        inc esi
    endm

Very interesting :t
Thanks

Setting stack statically (to 95000) :

Code Select Expand

0012FF8C at start
103000  algo19
98000  algo18
93000  algo17
88000  algo16
83000  algo15
78000  algo14
73000  algo13
68000  algo12
63000  algo11
58000  algo10
53000  algo9
48000  algo8
43000  algo7
38000  algo6
33000  algo5
28000  algo4
23000  algo3
18000  algo2
13000  algo1
8000  algo0

ok?
0012FF8C at end
Press any key to continue ...
Apparently also there is dinamically at least 2 pages of 4k

[aw27]

The only switch that I really need is the one that blocks certain trolls from my threads :P

Your threads? Nothing here is yours, although you use the forum resources to spam your buggy crapware without any shame.

[jj2007]

you use the forum resources to spam your buggy crapware without any shame.

Writes the guy whose posts are always signed with Visit nottp://www.atelierweb.com

[HSE]

It's very encouraging. Programming Masm... you never grow up   

[aw27]

Writes the guy whose posts are always signed with Visit nottp://www.atelierweb.com

Distracting attempt, I am talking about the guy that diverts every newbie to an obscure page on the webalice.it site on the pretext of explaining what Masm32 is all about when the sole purpose is to start the indoctrination about his crapware. It really sucks, these dirty tricks.

[jj2007]

an obscure page on the webalice.it site on the pretext of explaining what Masm32 is all about when the sole purpose is to start the indoctrination about his crapware.

The "obscure page" (http://www.webalice.it/jj2006/Masm32_Tips_Tricks_and_Traps.htm) is a very condensed two-pager with essential step-by-step instructions on how to install the Masm32 SDK, plus three lines on MasmBasic and one on JWasm (which is outdated, I will change that soon). The bulk of that page is

- a Hello World in pure Masm32
- another one showing the use of local variables
- a list of help files and tutorials
- hints on how to avoid frequent n00b errors, such as register preservation, misunderstandings about signed registers
- hints on frequent problems, like inkey combined with gui builds
and so on.

So that is about 1% MasmBasic, the rest is help for beginners that is difficult to find by scrolling through thousands of forum pages.

What makes you so absolutely furious about this little page, dear forum member AW? That nobody ever looks at Atelier Web? If there was anything relevant for an assembly n00b on your site, I would even include your signature ("Visit http://www.atelierweb.com") in my two-pager, but I find the Iczelion tutorials or Randy's Art of Assembly much more interesting for n00bs.

I am a hobby coder. I know I am privileged not having to earn a living with coding. Sorry that your business is not doing well, sorry that you feel obliged to kill your precious time hanging around here, but can you please stop dumping your accumulated hatred in this forum? Have I ever called your professional hacking software "buggy crapware"? What makes you believe that you have the right to insult other forum members, not only me, when your bowels are acting up?

[aw27]

Another pathetic and idiotic attempt to divert attention. You won this time I will explain a little.
My business is doing very well, I live from it for nearly 20 years and even have to pay other people to help me. At this stage of my life I can afford to spend more time doing things that give me some pleasure like ASM. That is the reason you see me here.
I don't live from Social Security as you appear to, since you are around the forum for many years without any income source or day job.
Note that I simply placed a link to my website as a signature, this is normal, and I never promoted any of my products here. My market is not this. Period.

Your link to webalice link is a complete source of misinformation and bad advices. Most newbies that come here know much more about programming in general than you ever dreamed about. After looking at your webalice they never come here again.

[jj2007]

I don't live from Social Security as you appear to

You are sick, José. Get a shrink and stop insulting people.

[hutch--]

 

I have always laughed at how well you guys get on together.  :P