github.com/lianghucheng/zrddz@v0.0.0-20200923083010-c71f680932e2/src/golang.org/x/sys/cpu/cpu_x86.go (about)

     1  // Copyright 2018 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  // +build 386 amd64 amd64p32
     6  
     7  package cpu
     8  
     9  const cacheLineSize = 64
    10  
    11  func init() {
    12  	Initialized = true
    13  
    14  	maxID, _, _, _ := cpuid(0, 0)
    15  
    16  	if maxID < 1 {
    17  		return
    18  	}
    19  
    20  	_, _, ecx1, edx1 := cpuid(1, 0)
    21  	X86.HasSSE2 = isSet(26, edx1)
    22  
    23  	X86.HasSSE3 = isSet(0, ecx1)
    24  	X86.HasPCLMULQDQ = isSet(1, ecx1)
    25  	X86.HasSSSE3 = isSet(9, ecx1)
    26  	X86.HasFMA = isSet(12, ecx1)
    27  	X86.HasSSE41 = isSet(19, ecx1)
    28  	X86.HasSSE42 = isSet(20, ecx1)
    29  	X86.HasPOPCNT = isSet(23, ecx1)
    30  	X86.HasAES = isSet(25, ecx1)
    31  	X86.HasOSXSAVE = isSet(27, ecx1)
    32  	X86.HasRDRAND = isSet(30, ecx1)
    33  
    34  	osSupportsAVX := false
    35  	// For XGETBV, OSXSAVE bit is required and sufficient.
    36  	if X86.HasOSXSAVE {
    37  		eax, _ := xgetbv()
    38  		// Check if XMM and YMM registers have OS support.
    39  		osSupportsAVX = isSet(1, eax) && isSet(2, eax)
    40  	}
    41  
    42  	X86.HasAVX = isSet(28, ecx1) && osSupportsAVX
    43  
    44  	if maxID < 7 {
    45  		return
    46  	}
    47  
    48  	_, ebx7, _, _ := cpuid(7, 0)
    49  	X86.HasBMI1 = isSet(3, ebx7)
    50  	X86.HasAVX2 = isSet(5, ebx7) && osSupportsAVX
    51  	X86.HasBMI2 = isSet(8, ebx7)
    52  	X86.HasERMS = isSet(9, ebx7)
    53  	X86.HasRDSEED = isSet(18, ebx7)
    54  	X86.HasADX = isSet(19, ebx7)
    55  }
    56  
    57  func isSet(bitpos uint, value uint32) bool {
    58  	return value&(1<<bitpos) != 0
    59  }