Adding Fp128 implementation based on fiat-crypto. #758
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Thanks @armfazh for working on this. Can you paste benchmarks for Nightly, just so we have those numbers as well? |
This was referenced Oct 4, 2023
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This is an implementation of Fp128 using fiat-crypto. The code generated needs a wrapper to implement the traits required by FieldElement.
The downside of this implementation is the performance observed. The latency for field multiplication is almost twice as the current human-produced code (#165 ).
Closes #757
Timings
Analisis
The critical part are the primitives: addcarryx, subborrowx, and mulx which are implemented using native-rust code.
Usually these primitives should be replaced by the compiler emitting a single assembler instruction (ADC,SBB,MUL, respectively).
Potential Solution:
It is possible to implement the primitives using intrinsics such as: carrying_add, borrowing_sub, and
widening_mul. However, they are only available in the nightly version.
I tested this approach in nightly, however there is still a performance regression.