[Prism54-devel] Prism54 development update

[Sebastien]

Hello,

> Which ARM emulator do you use?

We have a section about ARM emulators on this Wiki page :
http://jbnote.free.fr/islsm/doku.php?id=re:firmware_reverse-engeneering_methodology

Jean Baptiste used Virtera to uncompress the firmware. Unfortunately, this is 
a proprietary product which doesn't allow us to define memory areas, so it 
can't really be used.
GDB can emulate ARM programs, but it just segfaulted when I tried it. Perhaps 
the Virtera modified version works better, I haven't tried.
ARMphetamine just doesn't compile, and uses obsolete functions and libraries.
QEMU looks good, but this is a bit complicated source since this is much more 
than a ARM emulator.
I have had good results using the ARMulator source from GDB which I began to 
modify to emulate the behaviour of the ISL chipset, and to map some hardware 
registers to the real device (using ioctls calls on the ISLLDR device node 
and the memory window). I found out about the LED this way, emulating the 
0.8.0 PCI FullMAC firmware on my USB SoftMAC device for instance (because 
this firmware turns the LED on during startup - it crashes later because the 
emulator is unfinished) :D
But this needs more modifications to be really usable for now, because 
ARMulator doesn't support ARM9 and its coprocessors so someone must add this. 
The SoftMAC firmwares don't even uncompress correctly (but they do with 
Virtera, this is not because of some Intersil/Conexant proprietary stuff, but 
really because the emulator lacks ARM9 support).
No reverse engineering is involved at all, and the modifications can also 
benefit GDB, so if someone feels up to the task ...:)
I have not published my modified source yet, because this is quite a hack for 
now, but I'll do if anyone's interested.

> I googled a bit and people seem to use one from
> http://www.simplescalar.com/ but their download page is broken (I press "I
> agree" and get error page).

I didn't know about this emulator - may be interesting. I'll have a look.