Identify processor from firmware update image

Hi

I have a portable recording device from Boss that I'd like to reverse-
engineer a bit. They've made firmware updates freely available on
their web pages.
What information can I extract from those images? I'd like to know
micro-controller model, compiler and used OS.
The update contains 3 .bin files, one of which is bootloader. I've
extracted all strings from images, and gained little information. Most
of it were assertion failures and text used in interface.

If anyone's willing to spare some time, here's the URL for images (754
KB):
http://www.rolandmusik.de/ftp/pub/downloads/tecfiles/G_bis_O/MBR_1v04.zip

Thanks for reading
Josip

To me it looks like a CISC processor.  The minimum instruction size is
8 bits.  An 8-bit relative branch instruction (BEQ or BNE?) is
apparently encoded as 0x4E followed by the offset.  Having such an
instruction points to a smaller processor, maybe comparable to 6502 or
Z80 (but not exactly them).

On Aug 17, 11:49=A0am, Marc Jet <jetm...@hotmail.com> wrote:
> To me it looks like a CISC processor. =A0The minimum instruction size is
> 8 bits. =A0An 8-bit relative branch instruction (BEQ or BNE?) is
> apparently encoded as 0x4E followed by the offset. =A0Having such an
> instruction points to a smaller processor, maybe comparable to 6502 or
> Z80 (but not exactly them).

Thanks for taking the time. How did you deduct the relative branch
instruction code?

This recording device operates on sample rate of 44100 Hz, with 16
bits per sample. It can decode and encode MP3. It is capable of
realtime sound processing with several filters applied. Some of the
source code filenames mentioned in firmware suggest that these DSP
algorithms are all executed on the same processor:
dsp_bg121.cpp
edt_ifx_dly.cpp (delay effect)
edt_ifx_trm.cpp (tremolo effect)
edt_ifx_flg.cpp (flanger effect)

So, either it is a processor with considerable more power than Z80 and
6502, or they're using some kind of 8-bit uC / DSP hybrid.
Perhaps you could give me few pointers to find more info from firmware
image?

Thanks
Josip

On Aug 17, 8:03=A0am, dex <josipmisko...@gmail.com> wrote:

> So, either it is a processor with considerable more power than Z80 and
> 6502, or they're using some kind of 8-bit uC / DSP hybrid.

Most likely an ASSP. Some Asian companies e.g. Sonix sell VERY cheap
DSPs, with an 8-bit controller core and a "sidecar" DSP.

On Aug 17, 2:30=A0pm, larwe <zwsdot...@gmail.com> wrote:
> On Aug 17, 8:03=A0am, dex <josipmisko...@gmail.com> wrote:
>
> > So, either it is a processor with considerable more power than Z80 and
> > 6502, or they're using some kind of 8-bit uC / DSP hybrid.
>
> Most likely an ASSP. Some Asian companies e.g. Sonix sell VERY cheap
> DSPs, with an 8-bit controller core and a "sidecar" DSP.

I guess so. I'll try to disassemble the unit and check chip markings,
but my hopes are not very high.


Thanks
Josip