Re: new gdb remote packet type

[Robert Picco <Robert.Picco@hp.com>]

Andrew Cagney wrote:

>> Andrew Cagney wrote:
>>
>>>>  you'd prefer that I use the q-packet mechanism? 
>>>
>>>
>>>
>>>
>>> Yes, the qPart packet was designed for exactly the situtation you 
>>> encountered.  It can specify a length/offset and return a short 
>>> transfer.
>>>
>>> Andrew
>>>
>>>
>> Hi:
>>
>> Does this represent what you are expecting of the qPart packet?  I 
>> saw no reason to export the type because this
>> packet is only useful in remote.c
>
>
> While not immediatly, it is going to eventually be exposed out side of 
> remote.c, so we need to get what goes across the wire right up front. 
> To that end:
>
> - use register sets
>
> Unlike the G-packet, where the byte layout is determined by GDB 
> internal data structure, the byte layout needs to be specified by the 
> inferior's regsets.  That in turn means specifying separate packets 
> for fetching all or part of each of "gregs", "fpregs", and "xpregs"(?).
>
> - specify offset/length
>
> I think your code is specifying a register number, it should view the 
> region as a sequence of bytes and fetch using offset/length.  This 
> information can be obtained using "regset.h" (although that interface 
> might need some massaging).
>
> - fetch lazy
>
> Just request the region for the requested register.  It's then up to 
> the remote end to determine that more/less of the region can be supplied.
>
> Eventually this will also be added to the target vector, however, for 
> the moment something more local is definitly fine.
>
> Andrew
>
>
Hi:

Well I must admit to being a little confused:)  My intent is to not 
introduce any architecture dependency in remote.c and just restructure 
the g-packet to match what the target wants.  I could be missing a point 
here but the regset stuff looks very architecture dependent and it would 
seem incorrect to use it in remote.c. 

Well for offset I am using the regnum.  We are inquirying whether the 
target wants the reg mapped in the g-packet .

We could fetch lazy but this isn't currently done by remote.c because 
most target g-packet payloads aren't very large. IA64 is the exception 
with a payload in excess of 10,000 bytes. 

I must be missing your larger objective here because  my limited 
knowledge of gdb is in remote.c.

thanks,

Bob