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Teehee



Joined: 05 Aug 2009
Posts: 570
Location: Brazil
Teehee
Code:
cmp byte[esi-1],0    

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Post 08 Oct 2011, 17:05
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ouadji



Joined: 24 Dec 2008
Posts: 1081
Location: Belgium
ouadji

esi ? a page fault ?

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Post 08 Oct 2011, 18:35
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typedef



Joined: 25 Jul 2010
Posts: 2913
Location: 0x77760000
typedef
check direction flag maybe
Post 08 Oct 2011, 19:29
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Teehee



Joined: 05 Aug 2009
Posts: 570
Location: Brazil
Teehee
> esi ? a page fault ?
could be!? Surprised

> check direction flag maybe
both crash:
Code:
cld
mov byte[esi-1],0
std
mov byte[esi-1],0    
Post 08 Oct 2011, 19:33
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Goplat



Joined: 15 Sep 2006
Posts: 181
Goplat
If the "cmp byte[esi-1],0" instruction crashes it can only be because ESI-1 is not a valid address. Without seeing more of your code there's no way for anyone to know why that would be.
Post 08 Oct 2011, 20:45
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ouadji



Joined: 24 Dec 2008
Posts: 1081
Location: Belgium
ouadji
Code:
;@Teehee
cld
mov byte[esi-1],0
std
mov byte[esi-1],0    
std, cld ?
but in this case it is not the direction flag that is causing the problem,
but it is also a page fault.
Only a page fault can trigger a crash with this code.
(or a power outage Wink )
A breakpoint just before, a good debugger ... (3 min)
100% agree with Goplat

edit:
cld and std does not affect cmp or mov

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Post 08 Oct 2011, 20:48
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typedef



Joined: 25 Jul 2010
Posts: 2913
Location: 0x77760000
typedef
ouadji wrote:

(or a power outage )

Which power outage are we talking about here Very Happy lol
Post 09 Oct 2011, 02:29
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Teehee



Joined: 05 Aug 2009
Posts: 570
Location: Brazil
Teehee
Goplat wrote:
If the "cmp byte[esi-1],0" instruction crashes it can only be because ESI-1 is not a valid address. Without seeing more of your code there's no way for anyone to know why that would be.

I just made a new file with just that instruction. Very Happy

Quote:
cld and std does not affect cmp or mov

LOL i forgot that haha

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Post 09 Oct 2011, 12:28
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