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7/25/2019 Ppt Low Latency Low Complexity
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7/25/2019 Ppt Low Latency Low Complexity
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Abstract
A new architecture for matching the data protected with an
error-correcting code (ECC) is presented in this brief to reduce
latency and complexity.
codeword of an ECC is usually represented in a systematic
form consisting of the raw data and the parity informationgenerated by encoding,.
proposed architecture parallelizes the comparison of the data
and that of the parity information.
o further reduce the latency and complexity, in addition, anew butterfly-formed weight accumulator (!"A) is proposed
for the efficient computation of the #amming distance.
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$n the decode and compare architecture, n-bit retrie%ed
codeword should first be decoded to extract the original &-bit
tag.
he extracted &-bit tag is then compared with the &-bit tag
field of incoming address whether tag is matched or not.As the retrie%ed codeword should go through decoder before
compared with incoming tag. critical path delay is high.
Previous Work
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Decode-and-Compare Architecture
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he critical path is too long.
'esign complexity(more processing elements)
Previous Work Drawbacks
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Encode -and Compare -Architecture:o resol%e the drawbac&s of the decode-and-compare
architecture, the decoding of a retrie%ed codeword is replaced
with the encoding of an incoming tag in the encode-and-
compare architecture
he comparison is to examine how many bits the two
codeswords differ, not to chec& if the two codewords are
exactly eual to each other
here are two types a%ailable based on calculation of
hamming distance
A-based encode-and compare architecture
!"A based encode-and compare architecture
Proposed work
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Encode-and-compare Architecture
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$n A-based architecture,
&-bit incoming tag is first encoded
to the corresponding n-bit codeword * and compared with an
n-bit retrie%ed codeword +
#owe%er it does not consider the fact that ECC codeword is
systematic code in which data parts and parity bits can beseparated
Contd
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As the data part of systematic codeword is immediately
a%ailable for comparison while the parity bits is compared
only after encoding
!"A based encode-and-compare architecture parellises the
comparison of data part and parity informationAs the compulsory saturation necessitates additional logic
circuitry, the complexity of a A is higher
Contd
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Timing diagram
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BWA based Encode-and-compare
architecture
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$t reduces the complexity
$t reduces latency compared to pre%ious wor&
Advantages of proposed BWA based
architecture
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Computing systems for data comparison such as
ag matching in a cache memor!
virtua"-to-ph!sica" address trans"ation in a trans"ation "ook
aside buffer#$B%&
'ata protection applications
Applications
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o reduce the latency and hardware complexity, a new
architecture has been presented for matching the data
protected with an ECC. o reduce the latency, the comparison
of the data is parallelized with the encoding process that
generates the parity information. he parallel operations areenabled based on the fact that the systematic codeword has
separate fields for the data and parity.
$n addition, an efficient processing architecture has been
presented to further minimize the latency and complexity. Asthe proposed architecture is effecti%e in reducing the latency
as well as the complexity considerably, it can be regarded as a
promising solution for the comparison of ECC-protected data.
Conc"usion
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