I created merge requests that have improvements of prime modulo functions of elliptic curves and scalar multiply of curve25519 and curve448 for s390x architecture https://git.lysator.liu.se/nettle/nettle/-/merge_requests/42 https://git.lysator.liu.se/nettle/nettle/-/merge_requests/43 The prime modulo functions are implemented using basic arithmetic instructions (including addition with carry and subtraction with borrow) while scalar multiply of curve25519 and curve448 takes advantage of hardware-accelerated instruction pcc (Perform Cryptographic Computation). Benchmark numbers of the patches are attached to the MR description.
regards, Mamone