# Function core::arch::riscv32::sha512sig1h

source ·

    pub unsafe fn sha512sig1h(rs1: u32, rs2: u32) -> u32

🔬This is a nightly-only experimental API. (`riscv_ext_intrinsics` #114544)
Available on RISC-V RV32 and target feature `zknh` only.
Expand description

Implements the high half of the Sigma1 transformation, as used in the SHA2-512 hash function [49] (Section 4.1.3).

This instruction is implemented on RV32 only. Used to compute the Sigma1 transform of the SHA2-512 hash function in conjunction with the sha512sig1l instruction. The transform is a 64-bit to 64-bit function, so the input and output are each represented by two 32-bit registers. This instruction must always be implemented such that its execution latency does not depend on the data being operated on.

Source: RISC-V Cryptography Extensions Volume I: Scalar & Entropy Source Instructions

Version: v1.0.1

Section: 3.33

## §Safety

This function is safe to use if the `zknh` target feature is present.