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Code or not Code?

Posted by arasium 
Code or not Code?
March 14, 2010 12:05AM
I'm trying to understqnd how modules are working. I'm actually on the first .app ot the ios38 (i think this is the DIP one) and i've this:

LOAD:20205B48 sub_20205B48:                           @ CODE XREF: sub_20200ACC+2Ep
LOAD:20205B48                                         @ sub_20200CAC+38p
LOAD:20205B48                 BX      PC
LOAD:20205B48 @ ---------------------------------------------------------------------------
LOAD:20205B4A                 .align 4
LOAD:20205B4C                 .arm
LOAD:20205B4C loc_20205B4C:                           @ CODE XREF: sub_20205B48j
LOAD:20205B4C                 B       dword_20203EA4
LOAD:20205B4C @ End of function sub_20205B48


LOAD:20203EA4 dword_20203EA4: .long 0xE6000250, 0xE12FFF1E

So, i don't understand how we can branch to something that isn't code!!! Or is this arm code (and ida is bugging) ? If yes
how can i dissassemble this portions of binary because the Makecode of ida isn't ok here.....

Thank you

Edited 2 time(s). Last edit at 03/14/2010 07:24AM by arasium.
Re: Code or not Code?
March 15, 2010 12:11PM
Those are undefined instructions, designed to trigger an exception as a way to execute a syscall.
See [wiibrew.org] for a longer explanation.
Re: Code or not Code?
March 15, 2010 12:22PM
Thank you tueidj, you help is always very apreciated :)
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