[ECOS] Debugging from ROM

[Bart Veer]

>>>>> "Rich" == Rich LeGrand <rich@charmedlabs.com> writes:

    Rich> I'm not sure if debugging from ROM is something that has
    Rich> been done very often with eCos and gdb -- perhaps
    Rich> targets/processors with hardware breakpoints allow this.

    <snip>

    Rich> Is this reasonable? It's likely that I've overlooked
    Rich> something or somethings. Or maybe this has been done
    Rich> before.. REgardless, any comments would be greatly
    Rich> appreciated.

It is theoretically possible, but not exactly mainstream. When doing
software development you don't want to change the contents of the ROM
all the time because usually that is much slower than downloading an
executable into RAM via a ROM monitor - unless you have special
hardware such as a PROM ICE or a gameboy advance linker. Also,
although some processors do support facilities like hardware
breakpoints these tend to be rather limited, e.g. a maximum of four. I
don't know how well gdb would cope with such limitations - remember
that some debug operations like single-stepping are also usually
implemented via breakpoints. However, it should be possible to get
something working by modifying the existing stubs code.

If you are thinking of experimenting with this, I would suggest using
a dedicated communication channel for gdb traffic - at least
initially. Later on you can think about sharing the serial line
between gdb and the application.

Bart

-- 
Bart Veer                       eCos Configuration Architect
http://www.ecoscentric.com/     The eCos and RedBoot experts

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