1 // Copyright 2018 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 gc && !purego 6 7 package chacha20 8 9 import "golang.org/x/sys/cpu" 10 11 var haveAsm = cpu.S390X.HasVX 12 13 const bufSize = 256 14 15 // xorKeyStreamVX is an assembly implementation of XORKeyStream. It must only 16 // be called when the vector facility is available. Implementation in asm_s390x.s. 17 // 18 //go:noescape 19 func xorKeyStreamVX(dst, src []byte, key *[8]uint32, nonce *[3]uint32, counter *uint32) 20 21 func (c *Cipher) xorKeyStreamBlocks(dst, src []byte) { 22 if cpu.S390X.HasVX { 23 xorKeyStreamVX(dst, src, &c.key, &c.nonce, &c.counter) 24 } else { 25 c.xorKeyStreamBlocksGeneric(dst, src) 26 } 27 } 28