Improved node/instance handling.

The INSTANCE keyword can not be used while a node is opened (since it changes
the node>instance field that is also used for allocating the necessary amount
of memory for an instance). Since I experienced some bad and hard-to-debug
crashes when accidentially running into this problem, I now added a proper
error handling to the INSTANCE keyword.
Also improved my-space, my-address and my-unit a little bit so that these
node specific words now can also be used without an active instance.

Signed-off-by: Thomas Huth <thuth@linux.vnet.ibm.com>
2 files changed