// FileInfo fields.
	if sys, ok := fi.Sys().(*Header); ok {
		// This FileInfo came from a Header (not the OS). Use the
		// original Header to populate all remaining fields.
		h.Uid = sys.Uid
		h.Gid = sys.Gid
		h.Uname = sys.Uname
		h.Gname = sys.Gname
		h.AccessTime = sys.AccessTime
		h.ChangeTime = sys.ChangeTime
		if sys.Xattrs != nil {
			h.Xattrs = make(map[string]string)

		var buf bytes.Buffer
		for pb.Next() {
			runOnce(&buf)
		}
	})
}

func writeTestsToFS(tests []WriteTest) fs.FS {
	fsys := fstest.MapFS{}
	for _, wt := range tests {
		fsys[wt.Name] = &fstest.MapFile{
			Data: wt.Data,
			Mode: wt.Mode,
		}
	}
	return fsys
}

func TestWriterAddFS(t *testing.T) {
	buf := new(bytes.Buffer)
	w := NewWriter(buf)
	tests := []WriteTest{
		{

pkg syscall (linux-arm-cgo), func TimevalToNsec(Timeval) int64
pkg syscall (linux-arm), func TimevalToNsec(Timeval) int64
pkg syscall (openbsd-386), const SYS_KILL = 122
pkg syscall (openbsd-386-cgo), const SYS_KILL = 122
pkg syscall (openbsd-amd64), const SYS_KILL = 122
pkg syscall (openbsd-amd64-cgo), const SYS_KILL = 122
pkg syscall (windows-386), const ERROR_DIR_NOT_EMPTY = 145
pkg syscall (windows-386), const ERROR_DIR_NOT_EMPTY Errno

	}
	return fi.fh.Modified.UTC()
}
func (fi headerFileInfo) Mode() fs.FileMode { return fi.fh.Mode() }
func (fi headerFileInfo) Type() fs.FileMode { return fi.fh.Mode().Type() }
func (fi headerFileInfo) Sys() any          { return fi.fh }

func (fi headerFileInfo) Info() (fs.FileInfo, error) { return fi, nil }

func (fi headerFileInfo) String() string {
	return fs.FormatFileInfo(fi)
}

The document is not comprehensive.
</p>

<p>
The assembler is based on the input style of the Plan 9 assemblers, which is documented in detail
<a href="https://9p.io/sys/doc/asm.html">elsewhere</a>.
If you plan to write assembly language, you should read that document although much of it is Plan 9-specific.
The current document provides a summary of the syntax and the differences with

func (f *fileListEntry) Mode() fs.FileMode { return fs.ModeDir | 0555 }
func (f *fileListEntry) Type() fs.FileMode { return fs.ModeDir }
func (f *fileListEntry) IsDir() bool       { return true }
func (f *fileListEntry) Sys() any          { return nil }

func (f *fileListEntry) ModTime() time.Time {
	if f.file == nil {
		return time.Time{}
	}
	return f.file.FileHeader.Modified.UTC()
}

		} else {
			items = make([]lex.Token, 0, 3)
		}
		for {
			tok = p.nextToken()
			if len(operands) == 0 && len(items) == 0 {
				if p.arch.InFamily(sys.ARM, sys.ARM64, sys.AMD64, sys.I386, sys.RISCV64) && tok == '.' {
					// Suffixes: ARM conditionals, RISCV rounding mode or x86 modifiers.
					tok = p.nextToken()
					str := p.lex.Text()
					if tok != scanner.Ident {

// It walks the directory tree starting at the root of the filesystem
// adding each file to the tar archive while maintaining the directory structure.
func (tw *Writer) AddFS(fsys fs.FS) error {
	return fs.WalkDir(fsys, ".", func(name string, d fs.DirEntry, err error) error {
		if err != nil {
			return err
		}
		if d.IsDir() {
			return nil
		}
		info, err := d.Info()
		if err != nil {

	}
	if got, want := fh2.ModifiedDate, fh.ModifiedDate; got != want {
		t.Errorf("ModifiedDate: got %d, want %d\n", got, want)
	}

	if sysfh, ok := fi.Sys().(*FileHeader); !ok && sysfh != fh {
		t.Errorf("Sys didn't return original *FileHeader")
	}
}

func TestFileHeaderRoundTrip(t *testing.T) {
	fh := &FileHeader{
		Name:             "foo.txt",
		UncompressedSize: 987654321,

pkg syscall (openbsd-386), const SYS_LSTAT = 293
pkg syscall (openbsd-386), const SYS_NANOSLEEP = 240
pkg syscall (openbsd-386), const SYS_SELECT = 93
pkg syscall (openbsd-386), const SYS_SETITIMER = 83
pkg syscall (openbsd-386), const SYS_SETTIMEOFDAY = 122
pkg syscall (openbsd-386), const SYS_STAT = 291
pkg syscall (openbsd-386), const SYS_STATFS = 307
pkg syscall (openbsd-386), const SYS_UTIMENSAT = 326