
 The Open Register command is a two-line command that allows examination
 and optional modification of a word of memory.  The command connot open
 a location within a task unless the task is fixed in memory.  The
 general two-line format of the Open command is:

	OPEn memory-address<+n|-n></keyword>
	(memory-address) (contents)/<value>terminator

 Where	memory-address is the 1- to 8-digit octal address to open.
	+n or -n is one or more optional octal numbers to be added to or
		subtracted from the memory address.
	(memory-address) is the actual absolute or virtual address
		being displayed, and is typed by the Open command.
	(contents) is the contents of the address being displayed, and
		is typed by the Open command.
	value is the new octal value to be placed in the location.
	terminator is one of the legal line terminators, selected from
		those listed in HELP OPEN TERMINATORS.

 Keywords:	/TASK=taskname		Address is relative to a fixed task.
		/PAR=partition-name	Address is relative to a partition.
		/KNL			Address is in EXEC kernel space.
		/DRV=dd:		Address is in driver, dd:.
 If no keyword is specified, the address is considered to be absolute.
2 TERMINATORS
 When the Open command types a display of a memory location, it pauses
 for input.  At this point, a new value may be optionally typed,
 followed by a terminator.  The new value, if specified, is stored in
 the open location; and a new location is opened and displayed depending
 on the terminator typed:

	ESC	   - ESCape or ALTMODE:  ESC (ALTMODE) terminates the
		     Open command and returns to MCR.
	CR	   - Carriage return:  open the next sequential location
	^CR	   - Up-arrow (circumflex) followed by carriage return:
		     open the previous sequential location.
	*CR or @CR - Asterisk or at-sign followed by carriage return:
		     open the location pointed to by the contents of the
		     current location.
	>CR	   - Right-angle-bracket carriage-return: treat the contents
		     of the open location as a branch and open the location
		     that would be the effective address of that branch.
		     It is not permissable to supply a value and close the
		     location with >.
