SD	X5, 4294967296(X6)		// ERROR "constant 4294967296 too large"
	SRLI	$1, X5, F1			// ERROR "expected integer register in rd position but got non-integer register F1"
	SRLI	$1, F1, X5			// ERROR "expected integer register in rs1 position but got non-integer register F1"
	FNES	F1, (X5)			// ERROR "needs an integer register output"

	// Don't skip comments: we need to count newlines.
	s.Mode = scanner.ScanChars |
		scanner.ScanFloats |
		scanner.ScanIdents |
		scanner.ScanInts |
		scanner.ScanStrings |
		scanner.ScanComments
	s.Position.Filename = name
	s.IsIdentRune = isIdentRune
	return &Tokenizer{
		s:    &s,
		base: src.NewFileBase(name, objabi.AbsFile(objabi.WorkingDir(), name, *flags.TrimPath)),
		line: 1,
		file: file,
	}
}

// a semicolon. We only have to worry about cases that can occur in an
// expression passed through gofmt, which means composite literals and
// (due to the printer possibly inserting newlines because of position
// information) operators.
var gofmtLineReplacer = strings.NewReplacer(
	// Want to replace \n without ; after everything from
	// https://golang.org/ref/spec#Operators_and_punctuation
	// EXCEPT ++ -- ) ] }

		abs = r.i + offset
	case io.SeekEnd:
		abs = int64(len(r.s)) + offset
	default:
		return 0, errors.New("bytes.Reader.Seek: invalid whence")
	}
	if abs < 0 {
		return 0, errors.New("bytes.Reader.Seek: negative position")
	}
	r.i = abs
	return abs, nil
}

// WriteTo implements the [io.WriterTo] interface.
func (r *Reader) WriteTo(w io.Writer) (n int64, err error) {
	r.prevRune = -1
	if r.i >= int64(len(r.s)) {

		{seek: io.SeekStart, off: 1, n: 1, want: "1"},
		{seek: io.SeekCurrent, off: 1, wantpos: 3, n: 2, want: "34"},
		{seek: io.SeekStart, off: -1, seekerr: "bytes.Reader.Seek: negative position"},
		{seek: io.SeekStart, off: 1 << 33, wantpos: 1 << 33, readerr: io.EOF},
		{seek: io.SeekCurrent, off: 1, wantpos: 1<<33 + 1, readerr: io.EOF},
		{seek: io.SeekStart, n: 5, want: "01234"},

	// but be prepared.
	s.base = base
}

func (s *Slice) Line() int {
	return s.line
}

func (s *Slice) Col() int {
	// TODO: Col is only called when defining a macro and all it cares about is increasing
	// position to discover whether there is a blank before the parenthesis.
	// We only get here if defining a macro inside a macro.
	// This imperfect implementation means we cannot tell the difference between
	//	#define A #define B(x) x

	// Text returns the original string representation of the token.
	Text() string
	// File reports the source file name of the token.
	File() string
	// Base reports the position base of the token.
	Base() *src.PosBase
	// SetBase sets the position base.
	SetBase(*src.PosBase)
	// Line reports the source line number of the token.
	Line() int
	// Col reports the source column number of the token.
	Col() int