internal/xcpu: Vendor golang.org/x/sys/cpu

Standard library does this too. Unfortunate wish they just exposed it in the
standard library. Perhaps we can isolate the specific code we need later.

go.mod

@@ -1,5 +1,3 @@
 module nhooyr.io/websocket
 
 go 1.19
-
-require golang.org/x/sys v0.17.0

go.sum

@@ -1,2 +0,0 @@
-golang.org/x/sys v0.17.0 h1:25cE3gD+tdBA7lp7QfhuV+rJiE9YXTcS3VG1SqssI/Y=
-golang.org/x/sys v0.17.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=

internal/xcpu/.gitattributes

@@ -0,0 +1,10 @@
+# Treat all files in this repo as binary, with no git magic updating
+# line endings. Windows users contributing to Go will need to use a
+# modern version of git and editors capable of LF line endings.
+#
+# We'll prevent accidental CRLF line endings from entering the repo
+# via the git-review gofmt checks.
+#
+# See golang.org/issue/9281
+
+* -text

internal/xcpu/.gitignore

@@ -0,0 +1,2 @@
+# Add no patterns to .gitignore except for files generated by the build.
+last-change

internal/xcpu/README.md

@@ -0,0 +1,3 @@
+# cpu
+
+Vendored from https://github.com/golang/sys

internal/xcpu/asm_aix_ppc64.s

@@ -0,0 +1,17 @@
+// Copyright 2018 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.
+
+//go:build gc
+
+#include "textflag.h"
+
+//
+// System calls for ppc64, AIX are implemented in runtime/syscall_aix.go
+//
+
+TEXT ·syscall6(SB),NOSPLIT,$0-88
+	JMP	syscall·syscall6(SB)
+
+TEXT ·rawSyscall6(SB),NOSPLIT,$0-88
+	JMP	syscall·rawSyscall6(SB)

internal/xcpu/byteorder.go

@@ -0,0 +1,66 @@
+// 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 xcpu
+
+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",
+		"loong64",
+		"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")
+}