mirror of
https://github.com/octoleo/syncthing.git
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94 lines
2.4 KiB
Go
94 lines
2.4 KiB
Go
// Minio Cloud Storage, (C) 2016 Minio, Inc.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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//
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package sha256
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// True when SIMD instructions are available.
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var avx512 = haveAVX512()
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var avx2 = haveAVX2()
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var avx = haveAVX()
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var ssse3 = haveSSSE3()
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var armSha = haveArmSha()
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// haveAVX returns true when there is AVX support
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func haveAVX() bool {
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_, _, c, _ := cpuid(1)
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// Check XGETBV, OXSAVE and AVX bits
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if c&(1<<26) != 0 && c&(1<<27) != 0 && c&(1<<28) != 0 {
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// Check for OS support
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eax, _ := xgetbv(0)
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return (eax & 0x6) == 0x6
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}
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return false
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}
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// haveAVX2 returns true when there is AVX2 support
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func haveAVX2() bool {
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mfi, _, _, _ := cpuid(0)
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// Check AVX2, AVX2 requires OS support, but BMI1/2 don't.
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if mfi >= 7 && haveAVX() {
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_, ebx, _, _ := cpuidex(7, 0)
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return (ebx & 0x00000020) != 0
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}
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return false
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}
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// haveAVX512 returns true when there is AVX512 support
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func haveAVX512() bool {
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mfi, _, _, _ := cpuid(0)
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// Check AVX2, AVX2 requires OS support, but BMI1/2 don't.
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if mfi >= 7 {
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_, _, c, _ := cpuid(1)
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// Only detect AVX-512 features if XGETBV is supported
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if c&((1<<26)|(1<<27)) == (1<<26)|(1<<27) {
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// Check for OS support
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eax, _ := xgetbv(0)
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_, ebx, _, _ := cpuidex(7, 0)
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// Verify that XCR0[7:5] = ‘111b’ (OPMASK state, upper 256-bit of ZMM0-ZMM15 and
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// ZMM16-ZMM31 state are enabled by OS)
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/// and that XCR0[2:1] = ‘11b’ (XMM state and YMM state are enabled by OS).
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if (eax>>5)&7 == 7 && (eax>>1)&3 == 3 {
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if ebx&(1<<16) == 0 {
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return false // no AVX512F
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}
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if ebx&(1<<17) == 0 {
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return false // no AVX512DQ
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}
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if ebx&(1<<30) == 0 {
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return false // no AVX512BW
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}
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if ebx&(1<<31) == 0 {
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return false // no AVX512VL
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}
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return true
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}
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}
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}
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return false
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}
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// haveSSSE3 returns true when there is SSSE3 support
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func haveSSSE3() bool {
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_, _, c, _ := cpuid(1)
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return (c & 0x00000200) != 0
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}
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