Calypso DSP reverse engineering front ...

Harald Welte laforge at
Fri Mar 19 03:49:50 UTC 2010

On Thu, Mar 18, 2010 at 09:48:16PM +0100, Sylvain Munaut wrote:
> Now that my IDA works nicely with the code. I started really digging
> into what it does.

thanks for your update.

> It's also interesting to note that the raw IQ values should still be
> in the API zone after demodulation :)

This is interesting, but almost expected.  As far as I understand it,
the DMA from the BSP can only transfer into the API RAM.  So unless that
portion of API ram is reused, the values inevitably still have to be

> * Third, when looking at the code, it sometimes look like a mess ...
> there is no calling convention that I can see, every function seem to
> have it's own way of making. 

It is normal for such code to be hand-crafted DSP assembly, so I'm not
surprised you won't see fixed calling conventions like a compiler would
generate (or a mixed C / assembly project would require).

- Harald Welte <laforge at> 
"Privacy in residential applications is a desirable marketing option."
                                                  (ETSI EN 300 175-7 Ch. A6)

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