Changeset 45477a3 in rtems

Timestamp:

Jul 17, 2003, 9:59:42 PM (18 years ago)

Author:

Joel Sherrill <joel.sherrill@…>

Branches:

4.10, 4.11, 4.8, 4.9, 5, master

Children:

718f981

Parents:

d62cfdf

Message:

2003-07-17 Joel Sherrill <joel@…>

PR 433/tools

• mips-stub.c: Patch from C. M. Heard <heard@…> described as:

The purpose of the patch is to make the stub ignore all
characters except '+' (ack) or '-' (nak) when it has transmitted a
packet and expects an acknowledgment. Without the patch,
putpacket() will retransmit each time it receives anything other
than '+' when expecting an ack, and that, bitter experience has
found, frequently results in the stub failing to sync up when
initially attaching to gdb.

I think that rtems users will notice significant improvement in
the of the mips stub if this patch is incorporated in the
distribution; certainly I did in my stand-aline environment. I
should hasten to add that it is only an improvement and not a 100%
cure for synchronization problems because '+' characters can (and
do) during as message data, and it's still possible for these to
be mistaken as acks. I have no idea how to fix that short of
redesigning the gdb-remote protocol.

Location:

c/src/lib/libbsp/mips/shared/gdbstub

Files:

• ChangeLog (modified) (1 diff)
• mips-stub.c (modified) (2 diffs)

c/src/lib/libbsp/mips/shared/gdbstub/ChangeLog

@@ +1 @@
+2003-07-17      Joel Sherrill <joel@OARcorp.com>
+
+        PR 433/tools
+        * mips-stub.c: Patch from C. M. Heard <heard@pobox.com> described as:
+
+        The purpose of the patch is to make the stub ignore all
+        characters except '+' (ack) or '-' (nak) when it has transmitted a
+        packet and expects an acknowledgment. Without the patch,
+        putpacket() will retransmit each time it receives anything other
+        than '+' when expecting an ack, and that, bitter experience has
+        found, frequently results in the stub failing to sync up when
+        initially attaching to gdb.
+
+        I think that rtems users will notice significant improvement in
+        the of the mips stub if this patch is incorporated in the
+        distribution; certainly I did in my stand-aline environment. I
+        should hasten to add that it is only an improvement and not a 100%
+        cure for synchronization problems because '+' characters can (and
+        do) during as message data, and it's still possible for these to
+        be mistaken as acks. I have no idea how to fix that short of
+        redesigning the gdb-remote protocol.
+
 2002-11-01      Joel Sherrill <joel@OARcorp.com>
 

c/src/lib/libbsp/mips/shared/gdbstub/mips-stub.c

@@ -604 +604 @@
 
 /*
+ * Get a positive/negative acknowledgment for a transmitted packet.
+ */
+static char
+getAck (void)
+{
+  char c;
+
+  do
+    {
+      c = getDebugChar ();
+    }
+  while ((c != '+') && (c != '-'));
+
+  return c;
+}
+
+
+/*
  * Send the packet in buffer and wait for a positive acknowledgement.
  */
@@ -649 +667 @@
       putDebugChar (lowhex (checksum));
     }
-  while  (getDebugChar () != '+');
+  while  (getAck () != '+');
 }