Simplify the EFM decoder logic #770
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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).
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
added
enhancement
ld-decode-tools
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Stop the linear search when an item is found, and store the correction table indexed by EFM value. This is about 5% faster on a good disc - it may have more impact on a disc that's doing lots of EFM corrections.