1
0
mirror of https://gitea.com/Sirherobrine23/tea.git synced 2024-08-20 20:57:25 +00:00
tea/vendor/golang.org/x/sys/cpu/hwcap_linux.go
6543 6cff3b1cc7 migrate src-d/go-git -> go-git/go-git (#128)
Merge branch 'master' into vendor-migrate-go-git

Merge branch 'master' into vendor-migrate-go-git

migrate src-d/go-git -> go-git/go-git

Co-authored-by: 6543 <6543@obermui.de>
Reviewed-on: https://gitea.com/gitea/tea/pulls/128
Reviewed-by: techknowlogick <techknowlogick@gitea.io>
Reviewed-by: Lunny Xiao <xiaolunwen@gmail.com>
2020-04-30 02:02:15 +00:00

57 lines
1.2 KiB
Go

// 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 {
buf, err := ioutil.ReadFile(procAuxv)
if err != 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 err
}
bo := hostByteOrder()
for len(buf) >= 2*(uintSize/8) {
var tag, val uint
switch uintSize {
case 32:
tag = uint(bo.Uint32(buf[0:]))
val = uint(bo.Uint32(buf[4:]))
buf = buf[8:]
case 64:
tag = uint(bo.Uint64(buf[0:]))
val = uint(bo.Uint64(buf[8:]))
buf = buf[16:]
}
switch tag {
case _AT_HWCAP:
hwCap = val
case _AT_HWCAP2:
hwCap2 = val
}
}
return nil
}