mirror of
https://github.com/refraction-networking/utls.git
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b2207a94a3
Implements detection of x86 cpu features that are used in the go standard library. Changes all standard library packages to use the new cpu package instead of using runtime internal variables to check x86 cpu features. Updates: #15403 Change-Id: I2999a10cb4d9ec4863ffbed72f4e021a1dbc4bb9 Reviewed-on: https://go-review.googlesource.com/41476 Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org> Reviewed-by: Keith Randall <khr@golang.org> Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org>
59 lines
1.3 KiB
Go
59 lines
1.3 KiB
Go
// Copyright 2017 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// +build 386 amd64 amd64p32
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package cpu
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const CacheLineSize = 64
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// cpuid is implemented in cpu_x86.s.
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func cpuid(eaxArg, ecxArg uint32) (eax, ebx, ecx, edx uint32)
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// xgetbv with ecx = 0 is implemented in cpu_x86.s.
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func xgetbv() (eax, edx uint32)
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func init() {
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maxId, _, _, _ := cpuid(0, 0)
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if maxId < 1 {
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return
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}
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_, _, ecx1, edx1 := cpuid(1, 0)
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X86.HasSSE2 = isSet(26, edx1)
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X86.HasSSE3 = isSet(0, ecx1)
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X86.HasPCLMULQDQ = isSet(1, ecx1)
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X86.HasSSSE3 = isSet(9, ecx1)
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X86.HasSSE41 = isSet(19, ecx1)
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X86.HasSSE42 = isSet(20, ecx1)
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X86.HasPOPCNT = isSet(23, ecx1)
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X86.HasAES = isSet(25, ecx1)
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X86.HasOSXSAVE = isSet(27, ecx1)
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osSupportsAVX := false
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// For XGETBV, OSXSAVE bit is required and sufficient.
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if X86.HasOSXSAVE {
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eax, _ := xgetbv()
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// Check if XMM and YMM registers have OS support.
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osSupportsAVX = isSet(1, eax) && isSet(2, eax)
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}
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X86.HasAVX = isSet(28, ecx1) && osSupportsAVX
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if maxId < 7 {
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return
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}
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_, ebx7, _, _ := cpuid(7, 0)
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X86.HasBMI1 = isSet(3, ebx7)
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X86.HasAVX2 = isSet(5, ebx7) && osSupportsAVX
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X86.HasBMI2 = isSet(8, ebx7)
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X86.HasERMS = isSet(9, ebx7)
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}
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func isSet(bitpos uint, value uint32) bool {
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return value&(1<<bitpos) != 0
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}
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