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// Copyright 2019 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// +build ppc64le,!gccgo,!appengine
package chacha20
import "encoding/binary"
const (
bufSize = 256
haveAsm = true
)
//go:noescape
func chaCha20_ctr32_vmx(out, inp *byte, len int, key *[8]uint32, counter *uint32)
func (c *Cipher) xorKeyStreamAsm(dst, src []byte) {
if len(src) >= bufSize {
chaCha20_ctr32_vmx(&dst[0], &src[0], len(src)-len(src)%bufSize, &c.key, &c.counter)
}
if len(src)%bufSize != 0 {
chaCha20_ctr32_vmx(&c.buf[0], &c.buf[0], bufSize, &c.key, &c.counter)
start := len(src) - len(src)%bufSize
ts, td, tb := src[start:], dst[start:], c.buf[:]
// Unroll loop to XOR 32 bytes per iteration.
for i := 0; i < len(ts)-32; i += 32 {
td, tb = td[:len(ts)], tb[:len(ts)] // bounds check elimination
s0 := binary.LittleEndian.Uint64(ts[0:8])
s1 := binary.LittleEndian.Uint64(ts[8:16])
s2 := binary.LittleEndian.Uint64(ts[16:24])
s3 := binary.LittleEndian.Uint64(ts[24:32])
b0 := binary.LittleEndian.Uint64(tb[0:8])
b1 := binary.LittleEndian.Uint64(tb[8:16])
b2 := binary.LittleEndian.Uint64(tb[16:24])
b3 := binary.LittleEndian.Uint64(tb[24:32])
binary.LittleEndian.PutUint64(td[0:8], s0^b0)
binary.LittleEndian.PutUint64(td[8:16], s1^b1)
binary.LittleEndian.PutUint64(td[16:24], s2^b2)
binary.LittleEndian.PutUint64(td[24:32], s3^b3)
ts, td, tb = ts[32:], td[32:], tb[32:]
}
td, tb = td[:len(ts)], tb[:len(ts)] // bounds check elimination
for i, v := range ts {
td[i] = tb[i] ^ v
}
c.len = bufSize - (len(src) % bufSize)
}
}
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