1The following Forth words can be used for debugging:
2
3   debug <xt> - Mark word for debugging
4   debug-off  - Unmark all words for debugging
5   resume     - Return from subordinate Forth interpreter
6
7The source debugger also implements the following commands when it has been activated:
8
9   Up - Unmark current word for debugging, mark parent and continue
10   Down - Mark next word for debugging
11   Trace - Continue execution until end of word displaying
12           debug information
13   Rstack - Display contents of the Rstack
14   Forth - Launch subordinate Forth interpreter
15
16An example session:
170 > see boot
18: boot
19  linefeed parse cr " platform-boot" $find if
20  execute then
21  2drop cr " Booting " type type cr "   ... not supported on this system." type cr
22  ;
23 ok
240 > debug boot
25Stepper keys: <space>/<enter> Up Down Trace Rstack Forth
26 ok
270 > boot
28: boot  ( Empty )
2900000000ffe26b08: linefeed  ( a )
3000000000ffe26b10: parse  ( ffec6e24 0 )
3100000000ffe26b18: cr
32 ( ffec6e24 0 )
3300000000ffe26b20: (")  ( ffec6e24 0 ffe26b30 d )
3400000000ffe26b40: $find  ( ffec6e24 0 ffe31710 ffffffffffffffff )
3500000000ffe26b48: do?branch  ( ffec6e24 0 ffe31710 )
3600000000ffe26b58: execute [sparc64] Booting file 'cdrom' with parameters ''
37Not a bootable ELF image
38Not a Linux kernel image
39Not a bootable a.out image
40Loading FCode image...
41Loaded 5936 bytes
42entry point is 0x4000
43Evaluating FCode...
44open isn't unique.
45Boot load failed.
46 ( Empty )
4700000000ffe26b60: dobranch  ( Empty )
4800000000ffe26bf8: (semis)
49[ Finished boot ]  ok
500 >
51