Feat/big endian long limbs #9625
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Before, limbs were stored in little-endian. But to use Arrays.mismatch to our advantage, it is better to have it big-endian. This commit makes UInt256.java big-endian in limbs. We still need to migrate all tests and benchmark. Signed-off-by: Thomas Zamojski <[email protected]>
Also added tests that were failing and now pass. Signed-off-by: Thomas Zamojski <[email protected]>
Signed-off-by: Thomas Zamojski <[email protected]>
Signed-off-by: Thomas Zamojski <[email protected]>
Small cleaning up of the private methods for addition and compareLimbs. Should be easier for the compiler. Signed-off-by: Thomas Zamojski <[email protected]>
UInt256 used int[] for limbs, primarily for simplicity, e.g. having the possibility to widen to long. However, methods exists to work with long[] and no widening. This commit implements long limbs. To avoid widening, we do: 1. add: overflow check 2. mul: native multiplyHigh (compiled to assembly mulq) 3. div: more complicated, see the gnump division paper. Signed-off-by: Thomas Zamojski <[email protected]>
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PR description
This PR introduces performance improvements on Mod and associated EVM arithmetics operations by implementing division on multi-precision long limbs instead of int limbs. The following is a short summary of benchmarks that were done compared to current (big-endian int limbs) implementation and the relative gain in percentage:
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doc-change-requiredlabel to this PR if updates are required.Locally, you can run these tests to catch failures early:
./gradlew spotlessApply./gradlew build./gradlew acceptanceTest./gradlew integrationTest./gradlew ethereum:referenceTests:referenceTests