62 lines
1.3 KiB
Go
62 lines
1.3 KiB
Go
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// Copyright 2018 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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//+build !amd64,!amd64p32,!386
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package cpu
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import (
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"encoding/binary"
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"io/ioutil"
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"runtime"
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)
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const (
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_AT_HWCAP = 16
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_AT_HWCAP2 = 26
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procAuxv = "/proc/self/auxv"
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uintSize uint = 32 << (^uint(0) >> 63)
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)
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// For those platforms don't have a 'cpuid' equivalent we use HWCAP/HWCAP2
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// These are initialized in cpu_$GOARCH.go
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// and should not be changed after they are initialized.
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var HWCap uint
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var HWCap2 uint
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func init() {
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buf, err := ioutil.ReadFile(procAuxv)
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if err != nil {
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panic("read proc auxv failed: " + err.Error())
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}
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pb := int(uintSize / 8)
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for i := 0; i < len(buf)-pb*2; i += pb * 2 {
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var tag, val uint
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switch uintSize {
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case 32:
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tag = uint(binary.LittleEndian.Uint32(buf[i:]))
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val = uint(binary.LittleEndian.Uint32(buf[i+pb:]))
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case 64:
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if runtime.GOARCH == "ppc64" {
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tag = uint(binary.BigEndian.Uint64(buf[i:]))
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val = uint(binary.BigEndian.Uint64(buf[i+pb:]))
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} else {
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tag = uint(binary.LittleEndian.Uint64(buf[i:]))
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val = uint(binary.LittleEndian.Uint64(buf[i+pb:]))
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}
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}
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switch tag {
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case _AT_HWCAP:
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HWCap = val
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case _AT_HWCAP2:
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HWCap2 = val
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}
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}
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doinit()
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}
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