The attached patch makes a few changes in MI memory commands, with the
goal of making it easy for frontend to just display memory view, even
around the boundaries of accessible memory. The changes are as follows:

- The code that reads memory is modified read around inaccessible memory
regions as defined by memory map, as opposed to giving error if the first
address to read happens to be inaccessible.
- If we think the memory should be readable, but get an error, we now use
binary search to find subrange at the beginning that is still readable.
With this patch, we do the same for the end. So, if the start address is not
readable but end address is, the readable tail will be returned.
- The current output of -data-read-memory is totally insane. This patch
introduces -data-read-memory-raw that clearly reports what regions were
read, and shows the data as hex string. I've also added -data-write-memory-raw
which, contrary to -data-write-memory can actually write *memory*, as opposed to
a single byte.

I've tested this against a certain bare-metal board, first with memory map and 
second with manually cleared memory map in GDB. In both cases, reads before 
and after accessible memory worked reasonably. 

OK?

Thanks,

-- 
Vladimir Prus
CodeSourcery
vladimir@codesourcery.com
(650) 331-3385 x722