add package

[bytom/vapor.git] / vendor / github.com / minio / blake2b-simd / cpuid.go

diff --git a/vendor/github.com/minio/blake2b-simd/cpuid.go b/vendor/github.com/minio/blake2b-simd/cpuid.go
new file mode 100644 (file)
index 0000000..a9f9550
--- /dev/null
+++ b/vendor/github.com/minio/blake2b-simd/cpuid.go
@@ -0,0 +1,60 @@
+// +build 386,!gccgo amd64,!gccgo
+
+// Copyright 2016 Frank Wessels <fwessels@xs4all.nl>
+//
+// 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
+
+func cpuid(op uint32) (eax, ebx, ecx, edx uint32)
+func cpuidex(op, op2 uint32) (eax, ebx, ecx, edx uint32)
+func xgetbv(index uint32) (eax, edx uint32)
+
+// True when SIMD instructions are available.
+var avx2 = haveAVX2()
+var avx = haveAVX()
+var ssse3 = haveSSSE3()
+
+// haveAVX returns true when there is AVX support
+func haveAVX() bool {
+       _, _, c, _ := cpuid(1)
+
+       // Check XGETBV, OXSAVE and AVX bits
+       if c&(1<<26) != 0 && c&(1<<27) != 0 && c&(1<<28) != 0 {
+               // Check for OS support
+               eax, _ := xgetbv(0)
+               return (eax & 0x6) == 0x6
+       }
+       return false
+}
+
+// haveAVX2 returns true when there is AVX2 support
+func haveAVX2() bool {
+       mfi, _, _, _ := cpuid(0)
+
+       // Check AVX2, AVX2 requires OS support, but BMI1/2 don't.
+       if mfi >= 7 && haveAVX() {
+               _, ebx, _, _ := cpuidex(7, 0)
+               return (ebx & 0x00000020) != 0
+       }
+       return false
+}
+
+// haveSSSE3 returns true when there is SSSE3 support
+func haveSSSE3() bool {
+
+       _, _, c, _ := cpuid(1)
+
+       return (c & 0x00000200) != 0
+}