7.2.4 ECC codes
To protect the differenet types of RAM, three different ECC codes are required.
- A 34-bit ECC with seven check bits
for the tag RAM of the data side.
- A 32-bit ECC with seven check bits for the data
RAM of the data side, the tag RAM of the instruction side, and the
tag RAMs of the SCU.
- A 64-bit ECC with eight check bits for the instruction
The 32-bit ECC check matrix can be a subset of the 34-bit
ECC check matrix, so that only two different ECC codes are required,
a 34-bit ECC and a 64-bit ECC.