[ECOS] Re: RedBoot+GDB+application combo question

[Savin Zlobec]

On Fri, 20 Feb 2004 at 20:43:49, Stephan Eisvogel wrote:

> Savin Zlobec wrote:
> > Is there any reason why 'dbtrap' instruction can't be used for breakpoints ?
> 
> It is a 32-bit instruction, which would mean that by putting a break on
> the first of two successive 16-bit instructions, the second would get
> corrupted by that dbtrap's second 16 bits. If this is the only BP, you
> could envision a case where -provided you take no overly excessive read
> impossible precautions during runtime- a jump from anywhere could target
> this second, now temporarily overwritten, instruction. Oops...
> 
> I did a lot of research for this processor looking for ways to make GDB
> debugging possible, "br *" and a periodic (10-30 Hz) NMI pulse were the
> only option I could come up with that looked promising. Since we do many
> many designs for this processor still, we at least have the hardware to
> debug this kind of stuff.

I'am aware of 16/32 bit gdb breakpoint instruction thing - it is just that
I somehow remember the 'dbtrap' as a 16 bit instruction (have to check that
in the docs).

savin

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