// Copyright 2019 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package cpu

import (
	"io/ioutil"
)

const (
	_AT_HWCAP  = 16
	_AT_HWCAP2 = 26

	procAuxv = "/proc/self/auxv"

	uintSize = int(32 << (^uint(0) >> 63))
)

// For those platforms don't have a 'cpuid' equivalent we use HWCAP/HWCAP2
// These are initialized in cpu_$GOARCH.go
// and should not be changed after they are initialized.
var hwCap uint
var hwCap2 uint

func readHWCAP() error {
	,  := ioutil.ReadFile(procAuxv)
	if  != nil {
		// e.g. on android /proc/self/auxv is not accessible, so silently
		// ignore the error and leave Initialized = false. On some
		// architectures (e.g. arm64) doinit() implements a fallback
		// readout and will set Initialized = true again.
		return 
	}
	 := hostByteOrder()
	for len() >= 2*(uintSize/8) {
		var ,  uint
		switch uintSize {
		case 32:
			 = uint(.Uint32([0:]))
			 = uint(.Uint32([4:]))
			 = [8:]
		case 64:
			 = uint(.Uint64([0:]))
			 = uint(.Uint64([8:]))
			 = [16:]
		}
		switch  {
		case _AT_HWCAP:
			hwCap = 
		case _AT_HWCAP2:
			hwCap2 = 
		}
	}
	return nil
}