Function syscall_bn254_double_impl 

pub fn syscall_bn254_double_impl(p: [u8; 64]) -> Result<[u8; 64], ExitCode>

BN254 curve point doubling.

Input format

p must be an affine point encoded as [x || y] in little-endian, where each coordinate is 32 bytes.

Safety

Caller must ensure coordinates are valid field elements (< modulus). No validation is performed — invalid input produces undefined output.