1 /* Memory-access and commands for remote NINDY process, for GDB.
2 Copyright (C) 1990-1991 Free Software Foundation, Inc.
3 Contributed by Intel Corporation. Modified from remote.c by Chris Benenati.
5 GDB is distributed in the hope that it will be useful, but WITHOUT ANY
6 WARRANTY. No author or distributor accepts responsibility to anyone
7 for the consequences of using it or for whether it serves any
8 particular purpose or works at all, unless he says so in writing.
9 Refer to the GDB General Public License for full details.
11 Everyone is granted permission to copy, modify and redistribute GDB,
12 but only under the conditions described in the GDB General Public
13 License. A copy of this license is supposed to have been given to you
14 along with GDB so you can know your rights and responsibilities. It
15 should be in a file named COPYING. Among other things, the copyright
16 notice and this notice must be preserved on all copies.
18 In other words, go ahead and share GDB, but don't try to stop
19 anyone else from sharing it farther. Help stamp out software hoarding!
23 Except for the data cache routines, this file bears little resemblence
24 to remote.c. A new (although similar) protocol has been specified, and
25 portions of the code are entirely dependent on having an i80960 with a
26 NINDY ROM monitor at the other end of the line.
29 /*****************************************************************************
31 * REMOTE COMMUNICATION PROTOCOL BETWEEN GDB960 AND THE NINDY ROM MONITOR.
37 * As far as NINDY is concerned, GDB is always in one of two modes: command
38 * mode or passthrough mode.
40 * In command mode (the default) pre-defined packets containing requests
41 * are sent by GDB to NINDY. NINDY never talks except in reponse to a request.
43 * Once the the user program is started, GDB enters passthrough mode, to give
44 * the user program access to the terminal. GDB remains in this mode until
45 * NINDY indicates that the program has stopped.
51 * GDB writes all input received from the keyboard directly to NINDY, and writes
52 * all characters received from NINDY directly to the monitor.
54 * Keyboard input is neither buffered nor echoed to the monitor.
56 * GDB remains in passthrough mode until NINDY sends a single ^P character,
57 * to indicate that the user process has stopped.
60 * GDB assumes NINDY performs a 'flushreg' when the user program stops.
66 * All info (except for message ack and nak) is transferred between gdb
67 * and the remote processor in messages of the following format:
72 * # is a literal character
74 * <info> ASCII information; all numeric information is in the
75 * form of hex digits ('0'-'9' and lowercase 'a'-'f').
78 * is a pair of ASCII hex digits representing an 8-bit
79 * checksum formed by adding together each of the
80 * characters in <info>.
82 * The receiver of a message always sends a single character to the sender
83 * to indicate that the checksum was good ('+') or bad ('-'); the sender
84 * re-transmits the entire message over until a '+' is received.
86 * In response to a command NINDY always sends back either data or
87 * a result code of the form "Xnn", where "nn" are hex digits and "X00"
88 * means no errors. (Exceptions: the "s" and "c" commands don't respond.)
90 * SEE THE HEADER OF THE FILE "gdb.c" IN THE NINDY MONITOR SOURCE CODE FOR A
91 * FULL DESCRIPTION OF LEGAL COMMANDS.
93 * SEE THE FILE "stop.h" IN THE NINDY MONITOR SOURCE CODE FOR A LIST
96 ******************************************************************************/
100 #include <sys/types.h>
106 #include "inferior.h"
111 #include "ieee-float.h"
114 #include <sys/ioctl.h>
115 #include <sys/file.h>
117 #include "nindy-share/ttycntl.h"
118 #include "nindy-share/demux.h"
119 #include "nindy-share/env.h"
120 #include "nindy-share/stop.h"
123 extern char *getenv();
124 extern char *mktemp();
126 extern char *coffstrip();
127 extern value
call_function_by_hand ();
128 extern void generic_mourn_inferior ();
130 extern struct target_ops nindy_ops
;
131 extern jmp_buf to_top_level
;
132 extern FILE *instream
;
133 extern struct ext_format ext_format_i960
[]; /* i960-tdep.c */
135 extern char ninStopWhy ();
137 int nindy_initial_brk
; /* nonzero if want to send an initial BREAK to nindy */
138 int nindy_old_protocol
; /* nonzero if want to use old protocol */
139 char *nindy_ttyname
; /* name of tty to talk to nindy on, or null */
141 #define DLE '\020' /* Character NINDY sends to indicate user program has
146 int nindy_fd
= 0; /* Descriptor for I/O to NINDY */
147 static int have_regs
= 0; /* 1 iff regs read since i960 last halted */
148 static int regs_changed
= 0; /* 1 iff regs were modified since last read */
150 extern char *exists();
151 static void dcache_flush (), dcache_poke (), dcache_init();
152 static int dcache_fetch ();
154 /* FIXME, we can probably use the normal terminal_inferior stuff here.
155 We have to do terminal_inferior and then set up the passthrough
156 settings initially. Thereafter, terminal_ours and terminal_inferior
157 will automatically swap the settings around for us. */
159 /* Restore TTY to normal operation */
161 static TTY_STRUCT orig_tty
; /* TTY attributes before entering passthrough */
166 ioctl( 0, TIOCSETN
, &orig_tty
);
170 /* Recover from ^Z or ^C while remote process is running */
172 static void (*old_ctrlc
)(); /* Signal handlers before entering passthrough */
175 static void (*old_ctrlz
)();
185 signal(SIGINT
, old_ctrlc
);
187 signal(SIGTSTP
, old_ctrlz
);
189 error("\n\nYou may need to reset the 80960 and/or reload your program.\n");
192 /* Clean up anything that needs cleaning when losing control. */
194 static char *savename
;
197 nindy_close (quitting
)
209 /* Open a connection to a remote debugger.
210 FIXME, there should be a way to specify the various options that are
211 now specified with gdb command-line options. (baud_rate, old_protocol,
214 nindy_open (name
, from_tty
)
215 char *name
; /* "/dev/ttyXX", "ttyXX", or "XX": tty to be opened */
220 error_no_arg ("serial port device name");
222 target_preopen (from_tty
);
226 have_regs
= regs_changed
= 0;
229 /* Allow user to interrupt the following -- we could hang if
230 * there's no NINDY at the other end of the remote tty.
233 nindy_fd
= ninConnect( name
, baud_rate
? baud_rate
: "9600",
234 nindy_initial_brk
, !from_tty
, nindy_old_protocol
);
239 error( "Can't open tty '%s'", name
);
242 savename
= savestring (name
, strlen (name
));
243 push_target (&nindy_ops
);
244 target_fetch_registers(-1);
247 /* User-initiated quit of nindy operations. */
250 nindy_detach (name
, from_tty
)
255 error ("Too many arguments");
262 printf("\tAttached to %s at %s bps%s%s.\n", savename
,
263 baud_rate
? baud_rate
: "9600",
264 nindy_old_protocol
? " in old protocol": "",
265 nindy_initial_brk
? " with initial break": "");
268 /******************************************************************************
270 * Download an object file to the remote system by invoking the "comm960"
271 * utility. We look for "comm960" in $G960BIN, $G960BASE/bin, and
272 * DEFAULT_BASE/bin/HOST/bin where
273 * DEFAULT_BASE is defined in env.h, and
274 * HOST must be defined on the compiler invocation line.
275 ******************************************************************************/
278 nindy_load( filename
, from_tty
)
283 struct cleanup
*old_chain
;
284 char *scratch_pathname
;
288 filename
= get_exec_file (1);
290 filename
= tilde_expand (filename
);
291 make_cleanup (free
, filename
);
293 scratch_chan
= openp (getenv ("PATH"), 1, filename
, O_RDONLY
, 0,
295 if (scratch_chan
< 0)
296 perror_with_name (filename
);
297 close (scratch_chan
); /* Slightly wasteful FIXME */
299 have_regs
= regs_changed
= 0;
300 mark_breakpoints_out();
304 tmpfile
= coffstrip(scratch_pathname
);
306 old_chain
= make_cleanup(unlink
,tmpfile
);
308 ninDownload( tmpfile
, !from_tty
);
309 /* FIXME, don't we want this merged in here? */
311 do_cleanups (old_chain
);
317 /* Return the number of characters in the buffer before the first DLE character.
323 char *buf
; /* Character buffer; NOT '\0'-terminated */
324 int n
; /* Number of characters in buffer */
328 for ( i
= 0; i
< n
; i
++ ){
329 if ( buf
[i
] == DLE
){
336 /* Tell the remote machine to resume. */
339 nindy_resume (step
, siggnal
)
342 if (siggnal
!= 0 && siggnal
!= stop_signal
)
343 error ("Can't send signals to remote NINDY targets.");
347 nindy_store_registers ();
354 /* Wait until the remote machine stops. While waiting, operate in passthrough
355 * mode; i.e., pass everything NINDY sends to stdout, and everything from
358 * Return to caller, storing status in 'status' just as `wait' would.
365 DEMUX_DECL
; /* OS-dependent data needed by DEMUX... macros */
366 char buf
[500]; /* FIXME, what is "500" here? */
368 unsigned char stop_exit
;
369 unsigned char stop_code
;
371 long ip_value
, fp_value
, sp_value
; /* Reg values from stop */
374 WSETEXIT( (*status
), 0 );
376 /* OPERATE IN PASSTHROUGH MODE UNTIL NINDY SENDS A DLE CHARACTER */
378 /* Save current tty attributes, set up signals to restore them.
380 ioctl( 0, TIOCGETP
, &orig_tty
);
381 old_ctrlc
= signal( SIGINT
, cleanup
);
383 old_ctrlz
= signal( SIGTSTP
, cleanup
);
386 /* Pass input from keyboard to NINDY as it arrives.
387 * NINDY will interpret <CR> and perform echo.
390 TTY_NINDYTERM( tty
);
391 ioctl( 0, TIOCSETN
, &tty
);
394 /* Go to sleep until there's something for us on either
395 * the remote port or stdin.
398 DEMUX_WAIT( nindy_fd
);
400 /* Pass input through to correct place */
402 n
= DEMUX_READ( 0, buf
, sizeof(buf
) );
403 if ( n
){ /* Input on stdin */
404 write( nindy_fd
, buf
, n
);
407 n
= DEMUX_READ( nindy_fd
, buf
, sizeof(buf
) );
408 if ( n
){ /* Input on remote */
409 /* Write out any characters in buffer preceding DLE */
410 i
= non_dle( buf
, n
);
416 /* There *was* a DLE in the buffer */
417 stop_exit
= ninStopWhy( &stop_code
,
418 &ip_value
, &fp_value
, &sp_value
);
419 if ( !stop_exit
&& (stop_code
==STOP_SRQ
) ){
424 /* Get out of loop */
425 supply_register (IP_REGNUM
, &ip_value
);
426 supply_register (FP_REGNUM
, &fp_value
);
427 supply_register (SP_REGNUM
, &sp_value
);
434 signal( SIGINT
, old_ctrlc
);
436 signal( SIGTSTP
, old_ctrlz
);
440 if ( stop_exit
){ /* User program exited */
441 WSETEXIT( (*status
), stop_code
);
442 } else { /* Fault or trace */
446 /* Make it look like a VAX trace trap */
450 /* The target is not running Unix, and its
451 faults/traces do not map nicely into Unix signals.
452 Make sure they do not get confused with Unix signals
453 by numbering them with values higher than the highest
454 legal Unix signal. code in i960_print_fault(),
455 called via PRINT_RANDOM_SIGNAL, will interpret the
460 WSETSTOP( (*status
), stop_code
);
464 /* Read the remote registers into the block REGS. */
466 /* This is the block that ninRegsGet and ninRegsPut handles. */
468 char local_regs
[16 * 4];
469 char global_regs
[16 * 4];
473 char fp_as_double
[4 * 8];
477 nindy_fetch_registers(regno
)
480 struct nindy_regs nindy_regs
;
485 ninRegsGet( (char *) &nindy_regs
);
488 bcopy (nindy_regs
.local_regs
, ®isters
[REGISTER_BYTE (R0_REGNUM
)], 16*4);
489 bcopy (nindy_regs
.global_regs
, ®isters
[REGISTER_BYTE (G0_REGNUM
)], 16*4);
490 bcopy (nindy_regs
.pcw_acw
, ®isters
[REGISTER_BYTE (PCW_REGNUM
)], 2*4);
491 bcopy (nindy_regs
.ip
, ®isters
[REGISTER_BYTE (IP_REGNUM
)], 1*4);
492 bcopy (nindy_regs
.tcw
, ®isters
[REGISTER_BYTE (TCW_REGNUM
)], 1*4);
493 for (regnum
= FP0_REGNUM
; regnum
< FP0_REGNUM
+ 4; regnum
++) {
494 dub
= unpack_double (builtin_type_double
,
495 &nindy_regs
.fp_as_double
[8 * (regnum
- FP0_REGNUM
)],
497 /* dub now in host byte order */
498 double_to_ieee_extended (ext_format_i960
, &dub
,
499 ®isters
[REGISTER_BYTE (regnum
)]);
502 registers_fetched ();
507 nindy_prepare_to_store()
509 nindy_fetch_registers(-1);
513 nindy_store_registers(regno
)
516 struct nindy_regs nindy_regs
;
520 bcopy (®isters
[REGISTER_BYTE (R0_REGNUM
)], nindy_regs
.local_regs
, 16*4);
521 bcopy (®isters
[REGISTER_BYTE (G0_REGNUM
)], nindy_regs
.global_regs
, 16*4);
522 bcopy (®isters
[REGISTER_BYTE (PCW_REGNUM
)], nindy_regs
.pcw_acw
, 2*4);
523 bcopy (®isters
[REGISTER_BYTE (IP_REGNUM
)], nindy_regs
.ip
, 1*4);
524 bcopy (®isters
[REGISTER_BYTE (TCW_REGNUM
)], nindy_regs
.tcw
, 1*4);
525 /* Float regs. Only works on IEEE_FLOAT hosts. */
526 for (regnum
= FP0_REGNUM
; regnum
< FP0_REGNUM
+ 4; regnum
++) {
527 ieee_extended_to_double (ext_format_i960
,
528 ®isters
[REGISTER_BYTE (regnum
)], &dub
);
529 /* dub now in host byte order */
530 /* FIXME-someday, the arguments to unpack_double are backward.
531 It expects a target double and returns a host; we pass the opposite.
532 This mostly works but not quite. */
533 dub
= unpack_double (builtin_type_double
, &dub
, &inv
);
534 /* dub now in target byte order */
535 bcopy ((char *)&dub
, &nindy_regs
.fp_as_double
[8 * (regnum
- FP0_REGNUM
)],
540 ninRegsPut( (char *) &nindy_regs
);
545 /* Read a word from remote address ADDR and return it.
546 * This goes through the data cache.
549 nindy_fetch_word (addr
)
552 return dcache_fetch (addr
);
555 /* Write a word WORD into remote address ADDR.
556 This goes through the data cache. */
559 nindy_store_word (addr
, word
)
563 dcache_poke (addr
, word
);
566 /* Copy LEN bytes to or from inferior's memory starting at MEMADDR
567 to debugger memory starting at MYADDR. Copy to inferior if
568 WRITE is nonzero. Returns the length copied.
570 This is stolen almost directly from infptrace.c's child_xfer_memory,
571 which also deals with a word-oriented memory interface. Sometime,
572 FIXME, rewrite this to not use the word-oriented routines. */
575 nindy_xfer_inferior_memory(memaddr
, myaddr
, len
, write
, target
)
580 struct target_ops
*target
; /* ignored */
583 /* Round starting address down to longword boundary. */
584 register CORE_ADDR addr
= memaddr
& - sizeof (int);
585 /* Round ending address up; get number of longwords that makes. */
587 = (((memaddr
+ len
) - addr
) + sizeof (int) - 1) / sizeof (int);
588 /* Allocate buffer of that many longwords. */
589 register int *buffer
= (int *) alloca (count
* sizeof (int));
593 /* Fill start and end extra bytes of buffer with existing memory data. */
595 if (addr
!= memaddr
|| len
< (int)sizeof (int)) {
596 /* Need part of initial word -- fetch it. */
597 buffer
[0] = nindy_fetch_word (addr
);
600 if (count
> 1) /* FIXME, avoid if even boundary */
603 = nindy_fetch_word (addr
+ (count
- 1) * sizeof (int));
606 /* Copy data to be written over corresponding part of buffer */
608 bcopy (myaddr
, (char *) buffer
+ (memaddr
& (sizeof (int) - 1)), len
);
610 /* Write the entire buffer. */
612 for (i
= 0; i
< count
; i
++, addr
+= sizeof (int))
615 nindy_store_word (addr
, buffer
[i
]);
622 /* Read all the longwords */
623 for (i
= 0; i
< count
; i
++, addr
+= sizeof (int))
626 buffer
[i
] = nindy_fetch_word (addr
);
632 /* Copy appropriate bytes out of the buffer. */
633 bcopy ((char *) buffer
+ (memaddr
& (sizeof (int) - 1)), myaddr
, len
);
638 /* The data cache records all the data read from the remote machine
639 since the last time it stopped.
641 Each cache block holds 16 bytes of data
642 starting at a multiple-of-16 address. */
644 #define DCACHE_SIZE 64 /* Number of cache blocks */
646 struct dcache_block
{
647 struct dcache_block
*next
, *last
;
648 unsigned int addr
; /* Address for which data is recorded. */
652 struct dcache_block dcache_free
, dcache_valid
;
654 /* Free all the data cache blocks, thus discarding all cached data. */
659 register struct dcache_block
*db
;
661 while ((db
= dcache_valid
.next
) != &dcache_valid
)
664 insque (db
, &dcache_free
);
669 * If addr is present in the dcache, return the address of the block
673 struct dcache_block
*
677 register struct dcache_block
*db
;
682 /* Search all cache blocks for one that is at this address. */
683 db
= dcache_valid
.next
;
684 while (db
!= &dcache_valid
)
686 if ((addr
& 0xfffffff0) == db
->addr
)
693 /* Return the int data at address ADDR in dcache block DC. */
696 dcache_value (db
, addr
)
697 struct dcache_block
*db
;
702 return (db
->data
[(addr
>>2)&3]);
705 /* Get a free cache block, put or keep it on the valid list,
706 and return its address. The caller should store into the block
707 the address and data that it describes, then remque it from the
708 free list and insert it into the valid list. This procedure
709 prevents errors from creeping in if a ninMemGet is interrupted
710 (which used to put garbage blocks in the valid list...). */
712 struct dcache_block
*
715 register struct dcache_block
*db
;
717 if ((db
= dcache_free
.next
) == &dcache_free
)
719 /* If we can't get one from the free list, take last valid and put
720 it on the free list. */
721 db
= dcache_valid
.last
;
723 insque (db
, &dcache_free
);
727 insque (db
, &dcache_valid
);
731 /* Return the contents of the word at address ADDR in the remote machine,
732 using the data cache. */
738 register struct dcache_block
*db
;
740 db
= dcache_hit (addr
);
743 db
= dcache_alloc ();
745 ninMemGet(addr
& ~0xf, (unsigned char *)db
->data
, 16);
747 db
->addr
= addr
& ~0xf;
748 remque (db
); /* Off the free list */
749 insque (db
, &dcache_valid
); /* On the valid list */
751 return (dcache_value (db
, addr
));
754 /* Write the word at ADDR both in the data cache and in the remote machine. */
756 dcache_poke (addr
, data
)
760 register struct dcache_block
*db
;
762 /* First make sure the word is IN the cache. DB is its cache block. */
763 db
= dcache_hit (addr
);
766 db
= dcache_alloc ();
768 ninMemGet(addr
& ~0xf, (unsigned char *)db
->data
, 16);
770 db
->addr
= addr
& ~0xf;
771 remque (db
); /* Off the free list */
772 insque (db
, &dcache_valid
); /* On the valid list */
775 /* Modify the word in the cache. */
776 db
->data
[(addr
>>2)&3] = data
;
778 /* Send the changed word. */
780 ninMemPut(addr
, (unsigned char *)&data
, 4);
784 /* The cache itself. */
785 struct dcache_block the_cache
[DCACHE_SIZE
];
787 /* Initialize the data cache. */
792 register struct dcache_block
*db
;
795 dcache_free
.next
= dcache_free
.last
= &dcache_free
;
796 dcache_valid
.next
= dcache_valid
.last
= &dcache_valid
;
797 for (i
=0;i
<DCACHE_SIZE
;i
++,db
++)
798 insque (db
, &dcache_free
);
803 nindy_create_inferior (execfile
, args
, env
)
812 error ("Can't pass arguments to remote NINDY process");
814 if (execfile
== 0 || exec_bfd
== 0)
815 error ("No exec file specified");
817 entry_pt
= (int) bfd_get_start_address (exec_bfd
);
821 #ifdef CREATE_INFERIOR_HOOK
822 CREATE_INFERIOR_HOOK (pid
);
825 /* The "process" (board) is already stopped awaiting our commands, and
826 the program is already downloaded. We just set its PC and go. */
828 inferior_pid
= pid
; /* Needed for wait_for_inferior below */
830 clear_proceed_status ();
832 #if defined (START_INFERIOR_HOOK)
833 START_INFERIOR_HOOK ();
836 /* Tell wait_for_inferior that we've started a new process. */
837 init_wait_for_inferior ();
839 /* Set up the "saved terminal modes" of the inferior
840 based on what modes we are starting it with. */
841 target_terminal_init ();
843 /* Install inferior's terminal modes. */
844 target_terminal_inferior ();
846 /* remote_start(args); */
847 /* trap_expected = 0; */
848 /* insert_step_breakpoint (); FIXME, do we need this? */
849 proceed ((CORE_ADDR
)entry_pt
, -1, 0); /* Let 'er rip... */
853 reset_command(args
, from_tty
)
858 error( "No target system to reset -- use 'target nindy' command.");
860 if ( query("Really reset the target system?",0,0) ){
861 send_break( nindy_fd
);
862 tty_flush( nindy_fd
);
867 nindy_kill (args
, from_tty
)
871 return; /* Ignore attempts to kill target system */
874 /* Clean up when a program exits.
876 The program actually lives on in the remote processor's RAM, and may be
877 run again without a download. Don't leave it full of breakpoint
881 nindy_mourn_inferior ()
883 remove_breakpoints ();
884 generic_mourn_inferior (); /* Do all the proper things now */
887 /* This routine is run as a hook, just before the main command loop is
888 entered. If gdb is configured for the i960, but has not had its
889 nindy target specified yet, this will loop prompting the user to do so.
891 Unlike the loop provided by Intel, we actually let the user get out
892 of this with a RETURN. This is useful when e.g. simply examining
893 an i960 object file on the host system. */
895 nindy_before_main_loop ()
900 setjmp(to_top_level
);
901 while (current_target
!= &nindy_ops
) { /* remote tty not specified yet */
902 if ( instream
== stdin
){
903 printf("\nAttach /dev/ttyNN -- specify NN, or \"quit\" to quit: ");
906 fgets( ttyname
, sizeof(ttyname
)-1, stdin
);
908 /* Strip leading and trailing whitespace */
909 for ( p
= ttyname
; isspace(*p
); p
++ ){
913 return; /* User just hit spaces or return, wants out */
915 for ( p2
= p
; !isspace(*p2
) && (*p2
!= '\0'); p2
++ ){
919 if ( !strcmp("quit",p
) ){
925 /* Now that we have a tty open for talking to the remote machine,
926 download the executable file if one was specified. */
927 if ( !setjmp(to_top_level
) && exec_bfd
) {
928 target_load (bfd_get_filename (exec_bfd
), 1);
933 /* Define the target subroutine names */
935 struct target_ops nindy_ops
= {
936 "nindy", "Remote serial target in i960 NINDY-specific protocol",
937 "Use a remote i960 system running NINDY connected by a serial line.\n\
938 Specify the name of the device the serial line is connected to.\n\
939 The speed (baud rate), whether to use the old NINDY protocol,\n\
940 and whether to send a break on startup, are controlled by options\n\
941 specified when you started GDB.",
942 nindy_open
, nindy_close
,
943 0, nindy_detach
, nindy_resume
, nindy_wait
,
944 nindy_fetch_registers
, nindy_store_registers
,
945 nindy_prepare_to_store
, 0, 0, /* conv_from, conv_to */
946 nindy_xfer_inferior_memory
, nindy_files_info
,
947 0, 0, /* insert_breakpoint, remove_breakpoint, */
948 0, 0, 0, 0, 0, /* Terminal crud */
951 call_function_by_hand
,
952 0, /* lookup_symbol */
953 nindy_create_inferior
,
954 nindy_mourn_inferior
,
955 process_stratum
, 0, /* next */
956 1, 1, 1, 1, 1, /* all mem, mem, stack, regs, exec */
957 0, 0, /* Section pointers */
958 OPS_MAGIC
, /* Always the last thing */
964 add_target (&nindy_ops
);
965 add_com ("reset", class_obscure
, reset_command
,
966 "Send a 'break' to the remote target system.\n\
967 Only useful if the target has been equipped with a circuit\n\
968 to perform a hard reset when a break is detected.");