Re: new gdb remote packet type

Robert Picco
2004-05-11T17:31:00Z

Andrew have you had an opportunity to review this?

thanks,

Bob
Robert Picco wrote:
Andrew Cagney wrote:

Anyway, it sounds like you might (dig dig) be more interested in the
attached patch+hack (fernando nasser gets credit for the patch, I
deny responsibility for the hack bit :-). It adds a P packet for
fetching individual registers which is something the existing remote
protocol spec doco hints at.

Andrew

Seems remote.c currently supports "P" packet for storing a single
register would you find a patch supporting the "p" packet for fetching
a single register to be acceptable? This would put the minimum
payload on the wire and complement the "P" packet. It's similar to
the patch (hack) you forwarded but a complete implementation.

Bob

*** gdb-6.1-orig/gdb/remote.c 2004-02-25 15:41:00.000000000 -0500
--- gdb-6.1/gdb/remote.c 2004-05-06 14:05:47.000000000 -0400
***************
*** 809,814 ****
--- 809,831 ----
show_packet_config_cmd (&remote_protocol_E);
}

+ static struct packet_config remote_protocol_p;
+ + static void
+ set_remote_protocol_p_packet_cmd (char *args, int from_tty,
+ struct cmd_list_element *c)
+ {
+ update_packet_config (&remote_protocol_p);
+ }
+ + static void
+ show_remote_protocol_p_packet_cmd (char *args, int from_tty,
+ struct cmd_list_element *c)
+ {
+ show_packet_config_cmd (&remote_protocol_p);
+ }
+ +
/* Should we try the 'P' (set register) request? */

***************
*** 2080,2085 ****
--- 2097,2103 ----
update_packet_config (&remote_protocol_e);
update_packet_config (&remote_protocol_E);
update_packet_config (&remote_protocol_P);
+ update_packet_config (&remote_protocol_p);
update_packet_config (&remote_protocol_qSymbol);
update_packet_config (&remote_protocol_vcont);
for (i = 0; i < NR_Z_PACKET_TYPES; i++)
***************
*** 3240,3245 ****
--- 3258,3293 ----
/* Read the remote registers into the block REGS. */
/* Currently we just read all the registers, so we don't use regnum. */

+ static int
+ fetch_register_using_p (int regnum)
+ {
+ struct remote_state *rs = get_remote_state ();
+ char *buf = alloca (rs->remote_packet_size), *p;
+ char regp[MAX_REGISTER_SIZE];
+ int i;
+ + buf[0] = 'p';
+ bin2hex((char *) &regnum, &buf[1], sizeof(regnum));
+ buf[9] = 0;
+ remote_send (buf, rs->remote_packet_size);
+ if (buf[0] != 0 && buf[0] != 'E') {
+ p = buf;
+ i = 0;
+ while (p[0] != 0) {
+ if (p[1] == 0) {
+ error("fetch_register_using_p: early buf termination");
+ return 0;
+ }
+ regp[i++] = fromhex (p[0]) * 16 + fromhex (p[1]);
+ p += 2;
+ }
+ regcache_raw_supply (current_regcache, regnum, regp);
+ return 1;
+ }
+ + return 0;
+ }
+ static void
remote_fetch_registers (int regnum)
{
***************
*** 3260,3265 ****
--- 3308,3338 ----
"Attempt to fetch a non G-packet register when this "
"remote.c does not support the p-packet.");
}
+ switch (remote_protocol_p.support)
+ {
+ case PACKET_DISABLE:
+ break;
+ case PACKET_ENABLE:
+ if (fetch_register_using_p (regnum))
+ return;
+ else
+ error ("Protocol error: p packet not recognized by stub");
+ case PACKET_SUPPORT_UNKNOWN:
+ if (fetch_register_using_p (regnum))
+ {
+ /* The stub recognized the 'p' packet. Remember this. */
+ remote_protocol_p.support = PACKET_ENABLE;
+ return;
+ }
+ else
+ {
+ /* The stub does not support the 'P' packet. Use 'G'
+ instead, and don't try using 'P' in the future (it
+ will just waste our time). */
+ remote_protocol_p.support = PACKET_DISABLE;
+ break;
+ }
+ }

sprintf (buf, "g");
remote_send (buf, (rs->remote_packet_size));
***************
*** 5419,5424 ****
--- 5492,5498 ----
show_remote_protocol_e_packet_cmd (args, from_tty, NULL);
show_remote_protocol_E_packet_cmd (args, from_tty, NULL);
show_remote_protocol_P_packet_cmd (args, from_tty, NULL);
+ show_remote_protocol_p_packet_cmd (args, from_tty, NULL);
show_remote_protocol_qSymbol_packet_cmd (args, from_tty, NULL);
show_remote_protocol_vcont_packet_cmd (args, from_tty, NULL);
show_remote_protocol_binary_download_cmd (args, from_tty, NULL);
***************
*** 5631,5636 ****
--- 5705,5717 ----
&remote_set_cmdlist, &remote_show_cmdlist,
1);

+ add_packet_config_cmd (&remote_protocol_p,
+ "p", "fetch-register",
+ set_remote_protocol_p_packet_cmd,
+ show_remote_protocol_p_packet_cmd,
+ &remote_set_cmdlist, &remote_show_cmdlist,
+ 1);
+ add_packet_config_cmd (&remote_protocol_Z[Z_PACKET_SOFTWARE_BP],
"Z0", "software-breakpoint",
set_remote_protocol_Z_software_bp_packet_cmd,