Re: new gdb remote packet type

[Robert Picco <Robert dot Picco at hp dot com>]

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,