Reworked version of Forth Source debugger (Mark Cave-Ayland)

This patch implements the following Forth words:

   debug <xt> - Mark word for debugging
   debug-off  - Unmark all words for debugging
   resume     - Return from subordinate Forth interpreter

The source debugger also implements the following commands when it has
been activated:

   Up - Unmark current word for debugging, mark parent and continue
   Down - Mark next word for debugging
   Trace - Continue execution until end of word displaying
           debug information
   Rstack - Display contents of the Rstack
   Forth - Launch subordinate Forth interpreter

Signed-off-by: Blue Swirl <blauwirbel@gmail.com>

git-svn-id: svn://coreboot.org/openbios/trunk/openbios-devel@611 f158a5a8-5612-0410-a976-696ce0be7e32

forth/bootstrap/interpreter.fs

@@ -12,6 +12,7 @@
 \ 
 
 0 value interactive?
+0 value terminate?
 
 : exit?
   interactive? 0= if
@@ -122,7 +123,8 @@ defer outer-interpreter
     refill 
 
     ['] interpret catch print-status
-  again
+    terminate?
+  until
 ; ['] outer-interpreter (to)
 
 \