* interp.c (UMEM_SEGMENTS): New define, set to 128.

	* interp.c (UMEM_SEGMENTS): New define, set to 128.
	(sim_size): Use UMEM_SEGMENTS rather than hardwired constant.
	(sim_close): Reset prog_bfd to NULL after closing it.  Also
	reset prog_bfd_was_opened_p after closing prog_bfd.
	(sim_load): Reset prog_bfd_was_opened_p after closing prog_bfd.
	(sim_create_inferior): Get start address from abfd not prog_bfd.
	(xfer_mem): Do bounds checking on addresses and return zero length
	read/write on bad addresses, rather than aborting.  Prepare to
	be able to handle xfers that cross segment boundaries, but not
	yet implemented.  Only emit debug message when d10v_debug is
	set as well as DEBUG being defined.