/usr/share/gocode/src/github.com/minio/sha256-simd/cpuid.go is in golang-github-minio-sha256-simd-dev 0.0~git20171213.ad98a36-3.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 | // 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 sha256
// True when SIMD instructions are available.
var avx512 = haveAVX512()
var avx2 = haveAVX2()
var avx = haveAVX()
var ssse3 = haveSSSE3()
var armSha = haveArmSha()
// 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
}
// haveAVX512 returns true when there is AVX512 support
func haveAVX512() bool {
mfi, _, _, _ := cpuid(0)
// Check AVX2, AVX2 requires OS support, but BMI1/2 don't.
if mfi >= 7 {
_, _, c, _ := cpuid(1)
// Only detect AVX-512 features if XGETBV is supported
if c&((1<<26)|(1<<27)) == (1<<26)|(1<<27) {
// Check for OS support
eax, _ := xgetbv(0)
_, ebx, _, _ := cpuidex(7, 0)
// Verify that XCR0[7:5] = ‘111b’ (OPMASK state, upper 256-bit of ZMM0-ZMM15 and
// ZMM16-ZMM31 state are enabled by OS)
/// and that XCR0[2:1] = ‘11b’ (XMM state and YMM state are enabled by OS).
if (eax>>5)&7 == 7 && (eax>>1)&3 == 3 {
if ebx&(1<<16) == 0 {
return false // no AVX512F
}
if ebx&(1<<17) == 0 {
return false // no AVX512DQ
}
if ebx&(1<<30) == 0 {
return false // no AVX512BW
}
if ebx&(1<<31) == 0 {
return false // no AVX512VL
}
return true
}
}
}
return false
}
// haveSSSE3 returns true when there is SSSE3 support
func haveSSSE3() bool {
_, _, c, _ := cpuid(1)
return (c & 0x00000200) != 0
}
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