diff -rwu clean/gdb-7.2.50.20101027/gdb/remote-sim.c working/gdb-7.2.50.20101027/gdb/remote-sim.c
--- clean/gdb-7.2.50.20101027/gdb/remote-sim.c	2010-08-10 05:39:26.000000000 +0100
+++ working/gdb-7.2.50.20101027/gdb/remote-sim.c	2010-11-16 11:07:54.398861201 +0000
@@ -527,9 +527,13 @@
       if (nr_bytes > 0 && nr_bytes != register_size (gdbarch, regno))
 	internal_error (__FILE__, __LINE__,
 			_("Register size different to expected"));
-      /* FIXME: cagney/2002-05-27: Should check `nr_bytes == 0'
-	 indicating that GDB and the SIM have different ideas about
-	 which registers are fetchable.  */
+      if (nr_bytes < 0)
+        internal_error (__FILE__, __LINE__,
+			_("Register %d not updated"), regno);
+      if (nr_bytes == 0)
+        warning (_("Register %s not updated"),
+                 gdbarch_register_name (gdbarch, regno));
+      
       if (remote_debug)
 	{
 	  printf_filtered ("gdbsim_store_register: %d", regno);
Only in working/gdb-7.2.50.20101027/gdb: remote-sim.c~
diff -rwu clean/gdb-7.2.50.20101027/sim/erc32/interf.c working/gdb-7.2.50.20101027/sim/erc32/interf.c
--- clean/gdb-7.2.50.20101027/sim/erc32/interf.c	2010-05-11 15:18:20.000000000 +0100
+++ working/gdb-7.2.50.20101027/sim/erc32/interf.c	2010-10-27 16:56:12.607262027 +0100
@@ -330,7 +330,7 @@
 	regval = (value[3] << 24) | (value[2] << 16)
 		 | (value[1] << 8) | value[0];
     set_regi(&sregs, regno, regval);
-    return -1;
+    return length;
 }
 
 
diff -rwu clean/gdb-7.2.50.20101027/sim/h8300/compile.c working/gdb-7.2.50.20101027/sim/h8300/compile.c
--- clean/gdb-7.2.50.20101027/sim/h8300/compile.c	2010-04-14 08:38:04.000000000 +0100
+++ working/gdb-7.2.50.20101027/sim/h8300/compile.c	2010-10-27 16:56:28.193119915 +0100
@@ -4715,7 +4715,7 @@
       h8_set_ticks (sd, longval);
       break;
     }
-  return -1;
+  return length;
 }
 
 int
diff -rwu clean/gdb-7.2.50.20101027/sim/m32c/gdb-if.c working/gdb-7.2.50.20101027/sim/m32c/gdb-if.c
--- clean/gdb-7.2.50.20101027/sim/m32c/gdb-if.c	2010-04-14 08:38:04.000000000 +0100
+++ working/gdb-7.2.50.20101027/sim/m32c/gdb-if.c	2010-10-27 16:57:29.622058082 +0100
@@ -502,7 +502,7 @@
 	default:
 	  fprintf (stderr, "m32c minisim: unrecognized register number: %d\n",
 		   regno);
-	  return -1;
+	  return 0;
 	}
     }
 
diff -rwu clean/gdb-7.2.50.20101027/sim/mn10300/interp.c working/gdb-7.2.50.20101027/sim/mn10300/interp.c
--- clean/gdb-7.2.50.20101027/sim/mn10300/interp.c	2004-06-26 23:18:18.000000000 +0100
+++ working/gdb-7.2.50.20101027/sim/mn10300/interp.c	2010-10-27 16:59:00.810068620 +0100
@@ -410,7 +410,7 @@
 		    int length)
 {
   State.regs[rn] = get_word (memory);
-  return -1;
+  return length;
 }
 
 
diff -rwu clean/gdb-7.2.50.20101027/sim/ppc/gdb-sim.c working/gdb-7.2.50.20101027/sim/ppc/gdb-sim.c
--- clean/gdb-7.2.50.20101027/sim/ppc/gdb-sim.c	2010-01-01 10:03:33.000000000 +0000
+++ working/gdb-7.2.50.20101027/sim/ppc/gdb-sim.c	2010-10-27 17:00:16.559040694 +0100
@@ -1289,7 +1289,7 @@
   const char *regname = regnum2name (regno);
 
   if (simulator == NULL || regname == NULL)
-    return -1;
+    return 0;
 
   TRACE(trace_gdb, ("sim_store_register(regno=%d(%s), buf=0x%lx)\n",
 		    regno, regname, (long)buf));
diff -rwu clean/gdb-7.2.50.20101027/sim/rx/gdb-if.c working/gdb-7.2.50.20101027/sim/rx/gdb-if.c
--- clean/gdb-7.2.50.20101027/sim/rx/gdb-if.c	2010-09-24 00:05:28.000000000 +0100
+++ working/gdb-7.2.50.20101027/sim/rx/gdb-if.c	2010-10-27 16:59:37.090066882 +0100
@@ -630,7 +630,7 @@
     default:
       fprintf (stderr, "rx minisim: unrecognized register number: %d\n",
 	       regno);
-      return -1;
+      return 0;
     }
 
   return size;
diff -rwu clean/gdb-7.2.50.20101027/sim/v850/interp.c working/gdb-7.2.50.20101027/sim/v850/interp.c
--- clean/gdb-7.2.50.20101027/sim/v850/interp.c	2010-03-31 00:43:03.000000000 +0100
+++ working/gdb-7.2.50.20101027/sim/v850/interp.c	2010-10-27 17:00:02.016083444 +0100
@@ -327,7 +327,7 @@
      int length;
 {
   State.regs[rn] = T2H_4 (*(unsigned32*)memory);
-  return -1;
+  return length;
 }
 
 void