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1 // Copyright 2017 The Go Authors. All rights reserved.
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2 // Use of this source code is governed by a BSD-style
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3 // license that can be found in the LICENSE file.
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4
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5 // Functions to access/create device major and minor numbers matching the
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6 // encoding used in NetBSD's sys/types.h header.
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7
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8 package unix
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9
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10 // Major returns the major component of a NetBSD device number.
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11 func Major(dev uint64) uint32 {
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12 return uint32((dev & 0x000fff00) >> 8)
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13 }
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14
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15 // Minor returns the minor component of a NetBSD device number.
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16 func Minor(dev uint64) uint32 {
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17 minor := uint32((dev & 0x000000ff) >> 0)
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18 minor |= uint32((dev & 0xfff00000) >> 12)
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19 return minor
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20 }
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21
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22 // Mkdev returns a NetBSD device number generated from the given major and minor
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23 // components.
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24 func Mkdev(major, minor uint32) uint64 {
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25 dev := (uint64(major) << 8) & 0x000fff00
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26 dev |= (uint64(minor) << 12) & 0xfff00000
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27 dev |= (uint64(minor) << 0) & 0x000000ff
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28 return dev
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29 }
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