Figure 4-1. Encode Operation: Hash Engine before Compression Engine
In this figure, the Hash engine only calculates the hash values on the RAW data. The 820x
can also calculate MAC values on the RAW data by setting the configuration fields
appropriately in the command structure. The 820x can only calculate hash or MAC values
when the Hash engine's position is before the Compression engine. In any other position,
the Hash engine can only calculate MAC values.
4.1.2
Hash Engine after Compression Engine
Figure 4-2 shows the data flow when the Hash engine position is after the Compression
engine and all four engines are enabled. In this configuration, the Hash engine calculates
the MAC value on the CMP data instead of the RAW data. The data flow for the remaining
engines is the same as described in Section 4.1.1, “Hash Engine before Compression
Engine".
820x – Data Sheet, DS-0157-D
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