# Nt1330 Unit 3 Assignment Code

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\subsection{Creation of Matching Entries ({\it MakeMatchingEntries'})} \label{sec:make-matching}
\label{sec:match}

Procedure ${\it MakeMatchingEntries'}$ takes a decoding entry set and a pattern as input and outputs a newly created set that contains the entries that match the input pattern. Note that not every entry in the newly created set is the same entry in the input entries because the exclusion conditions were modified. The exclusion conditions that are invalidated by the input pattern are removed from the exclusion condition set of output entries. In addition, when all the matching patterns are invalidated, the unmatching patterns are expanded to their opcode patterns.

Procedure ${\it MakeMatchingEntries'}$ consists of the following …show more content…

Procedure $\it {MakeMatchingEntries'}$ updates all bits $p_c[i]$ of the matching and unmatching patterns in the exclusion condition with $p_c'[i]$ as follows:
\label{eqn:update} p_c'[i] \gets \begin{cases} p_c[i] & (p[i] = -) \\ - & (otherwise) \end{cases}

\subsubsection*{Step 4}

As a result of {\it Step 3}, there is a case where all the bits of the matching pattern are $\verb|-|$: when the matching condition has been satisfied and the unmatching conditions have not been satisfied yet. In this step, we expand the exclusion condition that contains only the unmatching pattern to its opcode pattern. Each bit in the opcode pattern in the updated entries has value $p_o'[i]$:
\label{expand}
p_o'[i] \gets \begin{cases} p_o[i] & (p_u[i] = -) \\ p_u[i] & (otherwise) \end{cases}

Note that the expanded decoding entries inherit the exclusion conditions except for the one that was expanded to the opcode