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