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Simplify the EFM decoder logic #770

Merged
merged 2 commits into from
Aug 20, 2022
Merged

Simplify the EFM decoder logic #770

merged 2 commits into from
Aug 20, 2022

Commits on Aug 12, 2022

  1. Simplify the logic in translateEfm. 

    Breaking out of the linear search when you find a match speeds this up
by about 5% (mostly from the first loop, since that handles 99.999% of
the values on a good disc).
    @atsampson
    atsampson committed Aug 12, 2022
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  2. Simplify the EFM correction table. 

    Since it contains an entry for every possible EFM code (with no
duplicates), it can be stored as a single array with the EFM code as the
index, avoiding the linear search.

(It's still quicker to use the linear search for the correct codes,
since the 512-byte lookup table fits in L1 cache; going straight to a
32+ KiB lookup table is much slower.)
    @atsampson
    atsampson committed Aug 12, 2022
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