Re: Adding-new-target difficulties

[Andrew Cagney <cagney@gnu.org>]

> Hello, 
> 
> [Note:  I'm adding support for ARMs RealView ICE to GDB] 
> 
> I'm trying to add a new target to GDB, but I'm not sure whether
> following the procedure in the user guide is going to give me what I
> want.  Is there a more straightforward way? 
> 
> I need a new target which allows me to communicate via tcp/ip but allows
> me to change the Remote Serial Protocol to RV-MSG (RealView Protocol). 
> The different protocol affects everything device; connect/disconnection,
> code loading, breakpoints, etc. 

(GDB's remote serial protocol?)

It sounds like you're trying to on-the-fly replace one target stack 
(gdb's remote) with a second (your protocol)?

Could you hack your new target (that used serial for tcp communication) 
fudge enough GDB remote protocol commands to trigger the mode switch?


> Where exactly does GDB spit stuff out for a TCP/IP connection?  I've
> been looking at remote.c and serial.c which seems to have functions
> related to it and another that looks promising is ser-tcp.c.  Could I
> simply add a switch to the command 'target remote host?'  Or add a case
> clause that detects if the hostname is 'RV-ICE' or something?  I could
> perhaps then branch off to my code, calling GDB functions as and when? 

Normally new remote targets are added as new commands vis:

	target remote
	target m32r
	target pmon
	target ...

this occures because the target*.c file has registered itself (see the 
_initialize function).  When the user enters "target ..." the 
corresponding ..._target_open being called.  After that it is a case of 
working through each of the vectors implementing those that are needed.

For the transport, yes serial.[hc] is used.

You may also want to look at the async code - it lets you implement 
things in a more event driven style.

Andrew