Fix PDO mapping with OD_ARRAY entries

The second entry is returned from co_entry_find(), for array or record
objects, when that entry has the OD_ARRAY flag set. So for these objects
the mapped entry pointer in the PDO will always point to the same entry
regardless of the subindex of the mapping.

Therefore, the PDO packing and unpacking must not consider the subindex
field of the mapped entry when storing or fetching the value. Instead it
needs to look at the actual mapped subindex to access the correct data.

Change-Id: I983f25bdeb10de72f7522d7a2f912e0c885e59fb

Author: nattgris

src/co_pdo.c

@@ -84,11 +84,12 @@ void co_pdo_pack (co_net_t * net, co_pdo_t * pdo)
       const co_entry_t * entry = pdo->entries[ix];
       const co_obj_t * obj     = pdo->objs[ix];
       size_t bitlength         = pdo->mappings[ix] & 0xFF;
+      uint8_t subindex         = (pdo->mappings[ix] >> 8) & 0xFF;
       uint64_t value           = 0;
 
       if (entry != NULL)
       {
-         co_od_get_value (net, obj, entry, entry->subindex, &value);
+         co_od_get_value (net, obj, entry, subindex, &value);
       }
 
       bitslice_set (&pdo->frame, offset, bitlength, value);
@@ -106,12 +107,13 @@ void co_pdo_unpack (co_net_t * net, co_pdo_t * pdo)
       const co_entry_t * entry = pdo->entries[ix];
       const co_obj_t * obj     = pdo->objs[ix];
       size_t bitlength         = pdo->mappings[ix] & 0xFF;
+      uint8_t subindex         = (pdo->mappings[ix] >> 8) & 0xFF;
       uint64_t value;
 
       if (entry != NULL)
       {
          value = bitslice_get (&pdo->frame, offset, bitlength);
-         co_od_set_value (net, obj, entry, entry->subindex, value);
+         co_od_set_value (net, obj, entry, subindex, value);
       }
 
       offset += bitlength;