Added AVX2 support (#6)

* Added AVX2 support

compressAvx2_amd64.go

@@ -0,0 +1,46 @@
+//+build !noasm
+//+build !appengine
+
+/*
+ * Minio Cloud Storage, (C) 2016 Minio, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package blake2b
+
+//go:noescape
+func compressAVX2Loop(p []uint8, in, iv, t, f, shffle, out []uint64)
+
+func compressAVX2(d *digest, p []uint8) {
+
+	in := make([]uint64, 8, 8)
+	out := make([]uint64, 8, 8)
+
+	shffle := make([]uint64, 8, 8)
+	// vector for PSHUFB instruction
+	shffle[0] = 0x0201000706050403
+	shffle[1] = 0x0a09080f0e0d0c0b
+	shffle[2] = 0x0201000706050403
+	shffle[3] = 0x0a09080f0e0d0c0b
+	shffle[4] = 0x0100070605040302
+	shffle[5] = 0x09080f0e0d0c0b0a
+	shffle[6] = 0x0100070605040302
+	shffle[7] = 0x09080f0e0d0c0b0a
+
+	in[0], in[1], in[2], in[3], in[4], in[5], in[6], in[7] = d.h[0], d.h[1], d.h[2], d.h[3], d.h[4], d.h[5], d.h[6], d.h[7]
+
+	compressAVX2Loop(p, in, iv[:], d.t[:], d.f[:], shffle, out)
+
+	d.h[0], d.h[1], d.h[2], d.h[3], d.h[4], d.h[5], d.h[6], d.h[7] = out[0], out[1], out[2], out[3], out[4], out[5], out[6], out[7]
+}