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Index > Non-x86 architectures > ARM SEL instruction and GE flags (parallel arithmetic)

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ippasm



Joined: 24 Oct 2013
Posts: 13
ippasm
Hi all,

I have been reading a lot about ARM assembly and I am interested on the GE flags associated with the SEL instruction. Specifically, I am interested in finding how can I manually get and set the values on those flags.

I would be very happy if someone could help...

Best regards,

ippasm
Post 25 Oct 2013, 10:59
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revolution
When all else fails, read the source


Joined: 24 Aug 2004
Posts: 17010
Location: In your JS exploiting you and your system
revolution
You can use MSR to set and/or clear any flags directly.
Post 25 Oct 2013, 12:18
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ippasm



Joined: 24 Oct 2013
Posts: 13
ippasm
Hi Revolution,

Could you please give a code example of how to set/get those flags? I have not been capabe of finding where they are placed on the msr and I have not found any code example....

Best regards,

ippasm

P.S. - Revolution, do you think there is a chance that fasmarm will ever be available as a dl (see http://board.flatassembler.net/topic.php?t=6239)?
Post 25 Oct 2013, 13:07
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revolution
When all else fails, read the source


Joined: 24 Aug 2004
Posts: 17010
Location: In your JS exploiting you and your system
revolution
GE3:GE0 are in the CPSR bits 19:16. You can write to them like this:
Code:
msr cpsr_s,0xf shl 16 ;set all of the GE flags to 1    
Post 25 Oct 2013, 14:00
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ippasm



Joined: 24 Oct 2013
Posts: 13
ippasm
Many thanks!

Coud you please answer the question regarding if fasmarm will ever be made available as a dll?

_________________
Best regards,

ippasm
Post 25 Oct 2013, 16:24
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revolution
When all else fails, read the source


Joined: 24 Aug 2004
Posts: 17010
Location: In your JS exploiting you and your system
revolution
Confused Perhaps. The use case is quite small so it is not high on my priority list ATM.
Post 25 Oct 2013, 21:59
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ippasm



Joined: 24 Oct 2013
Posts: 13
ippasm
Ok! Thanks anyway!

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Best regards,

ippasm
Post 28 Oct 2013, 10:14
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