During testing a scenario arose, where a toggling in the last_word
signal lane while the rest of the signals were not valid was falsely
latched.
All entities with "last_word_in" latches were modifies to only latch
the signal when in valid state.
Until now it was assumed that a serialized key is the PLAIN_CDR2
Big Endian encoding of a <TYPENAME>KeyHolder Object [DDS_XTYPES v1.3, 7.6.8]
(I.e. the same blob that computes the MD5 key hash).
Taking other DDS implementations as reference (e.g. Cyclone DDS), it
seems they are using a normal Payload containing a KeyHolder(<TYPENAME>)
Object [DDS_XTYPES v1.3, 7.2.2.4.7] as the serialized key.
The Key Holder Template (together with the Type1 and Type2
implementations) were updated to reflect this change.
A bug fix were the Key Hash was not reset on a 'PUSH_SERIALIZED_KEY'
opcode was also fixed (together with the testbench).
The instantiation of the KEY related entities is moved outside the DDS
Endpoints (Currently only changed in DDS Writer). Define new KEY_HOLDER
entity that is responsible for all Key related type-specific code.
Fix syntax of DDS Writer, and misc code refactoring.
