sha256block_ppc64x.go

     1  // Copyright 2024 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  //go:build (ppc64 || ppc64le) && !purego
     6  
     7  package sha256
     8  
     9  import (
    10  	"crypto/internal/impl"
    11  	"internal/godebug"
    12  )
    13  
    14  // The POWER architecture doesn't have a way to turn off SHA-2 support at
    15  // runtime with GODEBUG=cpu.something=off, so introduce a new GODEBUG knob for
    16  // that. It's intentionally only checked at init() time, to avoid the
    17  // performance overhead of checking it on every block.
    18  var ppc64sha2 = godebug.New("#ppc64sha2").Value() != "off"
    19  
    20  func init() {
    21  	impl.Register("crypto/sha256", "POWER8", &ppc64sha2)
    22  }
    23  
    24  //go:noescape
    25  func blockPOWER(dig *Digest, p []byte)
    26  
    27  func block(dig *Digest, p []byte) {
    28  	if ppc64sha2 {
    29  		blockPOWER(dig, p)
    30  	} else {
    31  		blockGeneric(dig, p)
    32  	}
    33  }
    34
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