B (Breakpoint) - Breakpoint install/remove

Format: B segment: address,[status]

     This command installs a breakpoint at a specified address. If the
processor encounters a breakpoint when running a program it interrupts the
program routine. The number in "status" parameter tells the breakpoint to
stay dormant and get activated only after processor comes across it a
specified number of times. Zero as "status" parameter removes the
breakpoint. On the display a command containing a breakpoint is marked with
the '+' symbol. Upon completion of the program run all breakpoints are
cancelled automatically.

ATTENTION! You cannot install a breakpoint in ROM. Any such attempts
           would be announced by a message "Can't set breakpoint in ROM'.