Preparing move to modules

[govpn.git] / internal / chacha20 / chacha_ppc64le.go

diff --git a/internal/chacha20/chacha_ppc64le.go b/internal/chacha20/chacha_ppc64le.go
new file mode 100644 (file)
index 0000000..638cb5e
--- /dev/null
+++ b/internal/chacha20/chacha_ppc64le.go
@@ -0,0 +1,52 @@
+// 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)
+
+       }
+
+}