github.com/icodeface/tls@v0.0.0-20230910023335-34df9250cd12/internal/cpu/cpu_x86.go (about)

     1  // Copyright 2017 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 CacheLinePadSize = 64
    10  
    11  // cpuid is implemented in cpu_x86.s.
    12  func cpuid(eaxArg, ecxArg uint32) (eax, ebx, ecx, edx uint32)
    13  
    14  // xgetbv with ecx = 0 is implemented in cpu_x86.s.
    15  func xgetbv() (eax, edx uint32)
    16  
    17  const (
    18  	// edx bits
    19  	cpuid_SSE2 = 1 << 26
    20  
    21  	// ecx bits
    22  	cpuid_SSE3      = 1 << 0
    23  	cpuid_PCLMULQDQ = 1 << 1
    24  	cpuid_SSSE3     = 1 << 9
    25  	cpuid_FMA       = 1 << 12
    26  	cpuid_SSE41     = 1 << 19
    27  	cpuid_SSE42     = 1 << 20
    28  	cpuid_POPCNT    = 1 << 23
    29  	cpuid_AES       = 1 << 25
    30  	cpuid_OSXSAVE   = 1 << 27
    31  	cpuid_AVX       = 1 << 28
    32  
    33  	// ebx bits
    34  	cpuid_BMI1 = 1 << 3
    35  	cpuid_AVX2 = 1 << 5
    36  	cpuid_BMI2 = 1 << 8
    37  	cpuid_ERMS = 1 << 9
    38  	cpuid_ADX  = 1 << 19
    39  )
    40  
    41  func doinit() {
    42  	options = []option{
    43  		{Name: "adx", Feature: &X86.HasADX},
    44  		{Name: "aes", Feature: &X86.HasAES},
    45  		{Name: "avx", Feature: &X86.HasAVX},
    46  		{Name: "avx2", Feature: &X86.HasAVX2},
    47  		{Name: "bmi1", Feature: &X86.HasBMI1},
    48  		{Name: "bmi2", Feature: &X86.HasBMI2},
    49  		{Name: "erms", Feature: &X86.HasERMS},
    50  		{Name: "fma", Feature: &X86.HasFMA},
    51  		{Name: "pclmulqdq", Feature: &X86.HasPCLMULQDQ},
    52  		{Name: "popcnt", Feature: &X86.HasPOPCNT},
    53  		{Name: "sse3", Feature: &X86.HasSSE3},
    54  		{Name: "sse41", Feature: &X86.HasSSE41},
    55  		{Name: "sse42", Feature: &X86.HasSSE42},
    56  		{Name: "ssse3", Feature: &X86.HasSSSE3},
    57  
    58  		// These capabilities should always be enabled on amd64(p32):
    59  		{Name: "sse2", Feature: &X86.HasSSE2, Required: GOARCH == "amd64" || GOARCH == "amd64p32"},
    60  	}
    61  
    62  	maxID, _, _, _ := cpuid(0, 0)
    63  
    64  	if maxID < 1 {
    65  		return
    66  	}
    67  
    68  	_, _, ecx1, edx1 := cpuid(1, 0)
    69  	X86.HasSSE2 = isSet(edx1, cpuid_SSE2)
    70  
    71  	X86.HasSSE3 = isSet(ecx1, cpuid_SSE3)
    72  	X86.HasPCLMULQDQ = isSet(ecx1, cpuid_PCLMULQDQ)
    73  	X86.HasSSSE3 = isSet(ecx1, cpuid_SSSE3)
    74  	X86.HasFMA = isSet(ecx1, cpuid_FMA)
    75  	X86.HasSSE41 = isSet(ecx1, cpuid_SSE41)
    76  	X86.HasSSE42 = isSet(ecx1, cpuid_SSE42)
    77  	X86.HasPOPCNT = isSet(ecx1, cpuid_POPCNT)
    78  	X86.HasAES = isSet(ecx1, cpuid_AES)
    79  	X86.HasOSXSAVE = isSet(ecx1, cpuid_OSXSAVE)
    80  
    81  	osSupportsAVX := false
    82  	// For XGETBV, OSXSAVE bit is required and sufficient.
    83  	if X86.HasOSXSAVE {
    84  		eax, _ := xgetbv()
    85  		// Check if XMM and YMM registers have OS support.
    86  		osSupportsAVX = isSet(eax, 1<<1) && isSet(eax, 1<<2)
    87  	}
    88  
    89  	X86.HasAVX = isSet(ecx1, cpuid_AVX) && osSupportsAVX
    90  
    91  	if maxID < 7 {
    92  		return
    93  	}
    94  
    95  	_, ebx7, _, _ := cpuid(7, 0)
    96  	X86.HasBMI1 = isSet(ebx7, cpuid_BMI1)
    97  	X86.HasAVX2 = isSet(ebx7, cpuid_AVX2) && osSupportsAVX
    98  	X86.HasBMI2 = isSet(ebx7, cpuid_BMI2)
    99  	X86.HasERMS = isSet(ebx7, cpuid_ERMS)
   100  	X86.HasADX = isSet(ebx7, cpuid_ADX)
   101  }
   102  
   103  func isSet(hwc uint32, value uint32) bool {
   104  	return hwc&value != 0
   105  }