memory region attribute CLI

[jtc at redback dot com (J.T. Conklin)]

I've been told to work on memory region attributes full time, so I
expect to make significant progress in the next few days.  

* create memory region:

        mem <start> <end> attribute [attribute ...]

  example:
        (gdb) mem 0x00008000 0x0000FFFF ro 8
        (gdb) mem 0x00007FF0 0x00007FFF rw
        (gdb) mem 0x00007FE0 0x00007FEF wo 16
        (gdb) mem 0x00007FD0 0x00007FDF ro
        

  I've followed the behavior of "display" and do not output a message
  indicating the number of the memory region that has been created.
  But as I write this message, it seems that it probably should.  I
  think an argument could be made that the same should be done for
  displays...

* enable/disable memory region:

        enable mem <region-id> [<region-id> ...]
        disable mem <region-id> [<region-id> ...]

  example:
        (gdb) disable mem 2

* delete memory regions:

        delete mem <region-id> [<region-id> ...]

  example:
        (gdb) delete mem 3

* show memory regions:

        info mem

  example:
        (gdb) info mem
        Num     Enb     Address                 Attr
        1:      y       0x00008000-0x0000FFFF   ro, 8
        2:      n       0x00007FF0-0x00007FFF   rw
        4:      y       0x00007FD0-0x00007FDF   ro

Thoughts?

        --jtc

-- 
J.T. Conklin
RedBack Networks