Re: how to debug mips or arm platform applications by cgdb

[Duane Ellis <duane@duaneellis.com>]

 >> Would someone tell me how to debug mips or arm applications by CGDB.

By CGDB, I presume you mean "cross gdb".

You need to describe your target better.

===========
(A)  Is your target running linux?
===========

If so, if your development host is not your target, (ie: cross work), 
you need a "gdb-server" application for your target. That "gdb server" 
would talk via RS232 (serial) or TCP/IP (ethernet) back to your 
development host.

You can "simulate" the TCP environment quite easily using "local host" 
on your development host so you can more easily understand how this 
works. It can be confusing the first few times you do it.

You can learn how to run "gdb server" on your development host, (aka: 
"local host"), and connect to the server using the GDB command: "target 
remote localhost:port" ...   90% of the battle is understanding how 
"gdbserver and target remote works" - doing that with "localhost" and a 
"development host program" is sometimes a little easier to understand 
and figure out.

Only then - change "target remote localhost" to   "target remote 
<ip-address-of-your-target-linux-board>".

===========
(B) is your target running standalone - no operating system, or 
something other then linux.
===========

For example, you might be debugging "UBOOT" or some other FLASH MEMORY 
type device, perhaps like: 'contiki' or 'freertos' or 'ethernut'

Some use JTAG to debug the Linux Kernel.

In this case, 2 options:

(a) A serial rom monitor that talks the GDB protocol (very rare these 
days, most people use jtag).

(b) A JTAG dongle, and software for that jtag dongle that understands 
the GDB protocol.

You'll need to *PURCHASE* a jtag dongle (or make one) - I highly 
recommend a "USB based ftdi-2232 based dongle", and *STRONGLY* do not 
recommend a "printer-port" solution.

The "jtag dongle method" - is 80% identical to the GDBREMOTE example 
above - but is more complicated (20%) because you have to create an 
initialization script to setup your target board, program the cpu 
clocks, erase & program the flash memory, stuff like that.

A *VERY* common JTAG solution (de-facto for ARM) is:  "openocd" - see:  
http://openocd.berlios.de/web

In the JTAG dongle case, GDB talks "target remote" to a GDB server 
program running on Linux, or Windows, or in some cases the DONGLE is 
really a tiny computer that talks the GDBSERVER protocol over Ethernet 
(the Zylin zy1000 is an example, it actually runs OpenOCD inside).

-Duane.