}
		// https://www.w3.org/TR/css3-syntax/#SUBTOK-escape
		// escape ::= unicode | '\' [#x20-#x7E#x80-#xD7FF#xE000-#xFFFD#x10000-#x10FFFF]
		if isHex(s[1]) {
			// https://www.w3.org/TR/css3-syntax/#SUBTOK-unicode
			//   unicode ::= '\' [0-9a-fA-F]{1,6} wc?
			j := 2
			for j < len(s) && j < 7 && isHex(s[j]) {
				j++
			}
			r := hexDecode(s[1:j])
			if r > unicode.MaxRune {
				r, j = r/16, j-1
			}

	// Count %, check that they're well-formed.
	percents := 0
	for i := 0; i < len(s); {
		if s[i] != '%' {
			i++
			continue
		}
		percents++
		if i+2 >= len(s) || !ishex(s[i+1]) || !ishex(s[i+2]) {
			s = s[i:]
			if len(s) > 3 {
				s = s[0:3]
			}
			return "", fmt.Errorf("mime: bogus characters after %%: %q", s)
		}
		i += 3
	}
	if percents == 0 {
		return s, nil

		// created by URI producers
		case '-', '.', '_', '~':
			continue
		case '%':
			// When normalizing do not re-encode valid escapes.
			if norm && i+2 < len(s) && isHex(s[i+1]) && isHex(s[i+2]) {
				continue
			}
		default:
			// Unreserved according to RFC 3986 sec 2.3
			if 'a' <= c && c <= 'z' {
				continue
			}
			if 'A' <= c && c <= 'Z' {
				continue
			}

		a := inst.Args[i]
		if a == nil {
			continue
		}
		args = append(args, plan9Arg(&inst, pc, symname, a))
	}

	var rep string
	var last Prefix
	for _, p := range inst.Prefix {
		if p == 0 || p.IsREX() || p.IsVEX() {
			break
		}

		switch {
		// Don't show prefixes implied by the instruction text.
		case p&0xFF00 == PrefixImplicit:
			continue
		// Only REP and REPN are recognized repeaters. Plan 9 syntax