SHA256 Optimization

Principles

Crypto instructions are added to the Armv8 instruction set, including hardware acceleration instructions related to the AES encryption/decryption algorithms, SHA1, and SHA256. This greatly improves the computing performance. Instructions for SHA256 optimization lists the instructions used for SHA256 optimization.

**Table 1** Instructions for SHA256 optimization
Instruction	Function	Example
SHA256H	SHA256 hash update (part 1)	SHA256H q0, q1, v2.4s
SHA256H2	SHA256 hash update (part 2)	SHA256H2 q0, q1, v2.4s
SHA256SU0	SHA256 schedule update 0	SHA256SU0 v0.4s, v1.4s
SHA256SU1	SHA256 schedule update 1	SHA256SU1 v0.4s, v1.4s, v2.4s

Modification Method

Replace the original implementation with the sha256_aarch64.S file, and add the Kunpeng function sha256_compress to the call position in the sha256.c file.

For details, see the Huawei Kunpeng forum at:

https://bbs.huaweicloud.com/forum/thread-138517-1-1.html

Parent topic: Optimization of Hot Functions