66 lines
1.8 KiB
Go
66 lines
1.8 KiB
Go
// Copyright 2019 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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package cpu
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import (
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"runtime"
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)
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// byteOrder is a subset of encoding/binary.ByteOrder.
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type byteOrder interface {
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Uint32([]byte) uint32
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Uint64([]byte) uint64
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}
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type littleEndian struct{}
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type bigEndian struct{}
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func (littleEndian) Uint32(b []byte) uint32 {
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_ = b[3] // bounds check hint to compiler; see golang.org/issue/14808
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return uint32(b[0]) | uint32(b[1])<<8 | uint32(b[2])<<16 | uint32(b[3])<<24
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}
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func (littleEndian) Uint64(b []byte) uint64 {
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_ = b[7] // bounds check hint to compiler; see golang.org/issue/14808
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return uint64(b[0]) | uint64(b[1])<<8 | uint64(b[2])<<16 | uint64(b[3])<<24 |
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uint64(b[4])<<32 | uint64(b[5])<<40 | uint64(b[6])<<48 | uint64(b[7])<<56
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}
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func (bigEndian) Uint32(b []byte) uint32 {
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_ = b[3] // bounds check hint to compiler; see golang.org/issue/14808
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return uint32(b[3]) | uint32(b[2])<<8 | uint32(b[1])<<16 | uint32(b[0])<<24
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}
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func (bigEndian) Uint64(b []byte) uint64 {
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_ = b[7] // bounds check hint to compiler; see golang.org/issue/14808
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return uint64(b[7]) | uint64(b[6])<<8 | uint64(b[5])<<16 | uint64(b[4])<<24 |
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uint64(b[3])<<32 | uint64(b[2])<<40 | uint64(b[1])<<48 | uint64(b[0])<<56
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}
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// hostByteOrder returns littleEndian on little-endian machines and
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// bigEndian on big-endian machines.
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func hostByteOrder() byteOrder {
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switch runtime.GOARCH {
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case "386", "amd64", "amd64p32",
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"alpha",
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"arm", "arm64",
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"mipsle", "mips64le", "mips64p32le",
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"nios2",
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"ppc64le",
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"riscv", "riscv64",
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"sh":
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return littleEndian{}
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case "armbe", "arm64be",
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"m68k",
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"mips", "mips64", "mips64p32",
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"ppc", "ppc64",
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"s390", "s390x",
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"shbe",
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"sparc", "sparc64":
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return bigEndian{}
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}
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panic("unknown architecture")
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}
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