github.com/guyezi/gofrontend@v0.0.0-20200228202240-7a62a49e62c0/libgo/go/internal/cpu/cpu_arm.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  package cpu
     6  
     7  // arm doesn't have a 'cpuid' equivalent, so we rely on HWCAP/HWCAP2.
     8  // These are linknamed in runtime/os_(linux|freebsd)_arm.go and are
     9  // initialized by archauxv().
    10  // These should not be changed after they are initialized.
    11  var HWCap uint
    12  var HWCap2 uint
    13  
    14  // HWCAP/HWCAP2 bits. These are exposed by Linux and FreeBSD.
    15  const (
    16  	hwcap_VFPv4 = 1 << 16
    17  	hwcap_IDIVA = 1 << 17
    18  )
    19  
    20  func doinit() {
    21  	options = []option{
    22  		{Name: "vfpv4", Feature: &ARM.HasVFPv4},
    23  		{Name: "idiva", Feature: &ARM.HasIDIVA},
    24  	}
    25  
    26  	// HWCAP feature bits
    27  	ARM.HasVFPv4 = isSet(HWCap, hwcap_VFPv4)
    28  	ARM.HasIDIVA = isSet(HWCap, hwcap_IDIVA)
    29  }
    30  
    31  func isSet(hwc uint, value uint) bool {
    32  	return hwc&value != 0
    33  }