sha1block_amd64.go

Documentation: crypto/sha1

		 1  // Copyright 2016 The Go Authors. All rights reserved.
		 2  // Use of this source code is governed by a BSD-style
		 3  // license that can be found in the LICENSE file.
		 4  
		 5  package sha1
		 6  
		 7  import "internal/cpu"
		 8  
		 9  //go:noescape
		10  func blockAVX2(dig *digest, p []byte)
		11  
		12  //go:noescape
		13  func blockAMD64(dig *digest, p []byte)
		14  
		15  var useAVX2 = cpu.X86.HasAVX2 && cpu.X86.HasBMI1 && cpu.X86.HasBMI2
		16  
		17  func block(dig *digest, p []byte) {
		18  	if useAVX2 && len(p) >= 256 {
		19  		// blockAVX2 calculates sha1 for 2 block per iteration
		20  		// it also interleaves precalculation for next block.
		21  		// So it may read up-to 192 bytes past end of p
		22  		// We may add checks inside blockAVX2, but this will
		23  		// just turn it into a copy of blockAMD64,
		24  		// so call it directly, instead.
		25  		safeLen := len(p) - 128
		26  		if safeLen%128 != 0 {
		27  			safeLen -= 64
		28  		}
		29  		blockAVX2(dig, p[:safeLen])
		30  		blockAMD64(dig, p[safeLen:])
		31  	} else {
		32  		blockAMD64(dig, p)
		33  	}
		34  }
		35
View as plain text