Month: March 2021

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AST LHS RHS

admin

https://www.codementor.io/@erikeidt/overview-of-a-compiler-zayyljs2s#evalutation-context-lhs-rhs-branch

https://en.wikipedia.org/wiki/Abstract_syntax_tree

https://en.wikipedia.org/wiki/Parse_tree

citation:

Left Hand Side vs. Right Hand Side

For example, in a = b + c, we evaluate the value of b and c, add them together, and then associate or store the result in a.  Here b and c have the context that we call right hand side — b and c are on the right hand side (of an assignment), whereas a has left hand side context — a is on the left hand side of an assignment.  We need the value of b and c yet the location of a to store the result.

A complex left hand side expression will itself also involve some right hand side evaluation.  For example, a[i] = 5 requires evaluting a and i as values (as if right hand side) and only the array indexing itself is evalutated as left hand side (for storage location).  5, of course, is understood as right hand side.

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ethicalh

cache replacement policies

admin

https://courses.cs.washington.edu/courses/cse451/17au/cache_scan.pdf

MIN

  • Replace the cache entry that will not be used for the
    longest time into the future
  • Optimality proof based on exchange: if evict an entry
    used sooner, that will trigger an earlier cache miss

Least Recently Used (LRU)

  • Replace the cache entry that has not been used for
    the longest time in the past
  • Approximation of MIN

Least Frequently Used (LFU)

  • Replace the cache entry used the least often (in the
    recent past)
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