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perf: eliminate redundant BigUint multiplications in Fp2MulSyscall #450

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Merged
eigmax merged 1 commit into from
Feb 15, 2026
Merged

perf: eliminate redundant BigUint multiplications in Fp2MulSyscall #450

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14 changes: 10 additions & 4 deletions crates/core/executor/src/syscalls/precompiles/fptower/fp2_mul.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -56,12 +56,18 @@ impl<P: FpOpField> Syscall for Fp2MulSyscall<P> {
let bc1 = &BigUint::from_slice(bc1);
let modulus = &BigUint::from_bytes_le(P::MODULUS);

// Pre-compute products to avoid redundant BigUint multiplications
let ac0_bc0 = (ac0 * bc0) % modulus;
let ac1_bc1 = (ac1 * bc1) % modulus;
let ac0_bc1 = (ac0 * bc1) % modulus;
let ac1_bc0 = (ac1 * bc0) % modulus;

#[allow(clippy::match_bool)]
let c0 = match (ac0 * bc0) % modulus < (ac1 * bc1) % modulus {
true => ((modulus + (ac0 * bc0) % modulus) - (ac1 * bc1) % modulus) % modulus,
false => ((ac0 * bc0) % modulus - (ac1 * bc1) % modulus) % modulus,
let c0 = match ac0_bc0 < ac1_bc1 {
true => ((modulus + &ac0_bc0) - &ac1_bc1) % modulus,
false => (&ac0_bc0 - &ac1_bc1) % modulus,
};
let c1 = ((ac0 * bc1) % modulus + (ac1 * bc0) % modulus) % modulus;
let c1 = (&ac0_bc1 + &ac1_bc0) % modulus;

let mut result = c0.to_u32_digits();
result.resize(num_words / 2, 0);
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