github.com/go-xe2/third@v1.0.3/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  	maxID, _, _, _ := cpuid(0, 0)
    13  
    14  	if maxID < 1 {
    15  		return
    16  	}
    17  
    18  	_, _, ecx1, edx1 := cpuid(1, 0)
    19  	X86.HasSSE2 = isSet(26, edx1)
    20  
    21  	X86.HasSSE3 = isSet(0, ecx1)
    22  	X86.HasPCLMULQDQ = isSet(1, ecx1)
    23  	X86.HasSSSE3 = isSet(9, ecx1)
    24  	X86.HasFMA = isSet(12, ecx1)
    25  	X86.HasSSE41 = isSet(19, ecx1)
    26  	X86.HasSSE42 = isSet(20, ecx1)
    27  	X86.HasPOPCNT = isSet(23, ecx1)
    28  	X86.HasAES = isSet(25, ecx1)
    29  	X86.HasOSXSAVE = isSet(27, ecx1)
    30  
    31  	osSupportsAVX := false
    32  	// For XGETBV, OSXSAVE bit is required and sufficient.
    33  	if X86.HasOSXSAVE {
    34  		eax, _ := xgetbv()
    35  		// Check if XMM and YMM registers have OS support.
    36  		osSupportsAVX = isSet(1, eax) && isSet(2, eax)
    37  	}
    38  
    39  	X86.HasAVX = isSet(28, ecx1) && osSupportsAVX
    40  
    41  	if maxID < 7 {
    42  		return
    43  	}
    44  
    45  	_, ebx7, _, _ := cpuid(7, 0)
    46  	X86.HasBMI1 = isSet(3, ebx7)
    47  	X86.HasAVX2 = isSet(5, ebx7) && osSupportsAVX
    48  	X86.HasBMI2 = isSet(8, ebx7)
    49  	X86.HasERMS = isSet(9, ebx7)
    50  	X86.HasADX = isSet(19, ebx7)
    51  }
    52  
    53  func isSet(bitpos uint, value uint32) bool {
    54  	return value&(1<<bitpos) != 0
    55  }