GDB Proto: Draft revised spec...

Todd Whitesel
Wed Jun 30 17:43:00 GMT 1999

>    'm' and 'M': Should probably mention that there is no alignment or
> 	width guarantees on either side.  GDB cannot assume a word
> 	sized read/write command will be performed with word sized
> 	access; likewise the stub cannot assume a word sized command
> 	will be word aligned, etc, etc, etc.

It would be a Very Good Thing to have some set of commands for forcing the
size/alignment of an access. Every now and then somebody has to debug code
that uses the VME bus (which is access size sensitive) or peripherals that
are only decoded properly when the right access size is used.

For a user to view pointer/struct variables that map to this hardware, GDB
needs to be able to recognize a "volatile" thing somehow and force the
accesses to be simple and unoptimized, or provide some other method. There
are actual customers out there who use GDB to get the address of something
and then type that into another tool which is able to control the access
size on the target.

This is a general problem with embedded debuggers; when I was at Green Hills
I added some little hacks to MULTI so that we could support this on at least
a few targets.

>     * The 'A' command seems out of place.  Program arguments are an
>       awfully high level concept for a low level protocol.

Not if your target is another unix machine. Does gdbserver use this protocol?

Todd Whitesel
toddpw @

More information about the Gdb mailing list