for _, c := range s {
		if c >= 0x80 || c == 0x00 {
			return false
		}
	}
	return true
}

// toASCII converts the input to an ASCII C-style string.
// This is a best effort conversion, so invalid characters are dropped.
func toASCII(s string) string {
	if isASCII(s) {
		return s
	}
	b := make([]byte, 0, len(s))
	for _, c := range s {
		if c < 0x80 && c != 0x00 {
			b = append(b, byte(c))
		}
	}

		0x07, 0x00, 0x00, 0x00, 0x07, 0x00, 0x00, 0x00,
		0x50, 0x4b, 0x01, 0x02, 0x14, 0x03, 0x14, 0x00,
		0x08, 0x00, 0x00, 0x00, 0x6b, 0xb4, 0xba, 0x46,
		0x1d, 0x88, 0x77, 0xb0, 0x07, 0x00, 0x00, 0x00,
		0x07, 0x00, 0x00, 0x00, 0x03, 0x00, 0x18, 0x00,
		0x20, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
		0xa0, 0x81, 0x00, 0x00, 0x00, 0x00, 0xca, 0x64,
		0x55, 0x75, 0x78, 0x0b, 0x00, 0x50, 0x4b, 0x05,

	LDAXRB (R19), R16                          // 70fe5f08
	LDAXRH (R5), R8                            // a8fc5f48
	//TODO LDNP 0xcc(RSP), ZR, R12             // ecff5928
	//TODO LDNP 0x40(R28), R9, R5              // 852744a8
	//TODO LDPSW -0xd0(R2), R0, R12            // 4c00e668
	//TODO LDPSW 0x5c(R4), R8, R5              // 85a0cb69
	//TODO LDPSW 0x6c(R12), R2, R27            // 9b894d69

	r13 := new(rot13Reader)
	r13.r = r
	return r13
}

func (r13 *rot13Reader) Read(p []byte) (int, error) {
	n, err := r13.r.Read(p)
	for i := 0; i < n; i++ {
		c := p[i] | 0x20 // lowercase byte
		if 'a' <= c && c <= 'm' {
			p[i] += 13
		} else if 'n' <= c && c <= 'z' {
			p[i] -= 13
		}
	}
	return n, err
}

// Call ReadByte to accumulate the text of a file

			prefix = p.parseString(ustar.prefix())

			// For Format detection, check if block is properly formatted since
			// the parser is more liberal than what USTAR actually permits.
			notASCII := func(r rune) bool { return r >= 0x80 }
			if bytes.IndexFunc(tr.blk[:], notASCII) >= 0 {
				hdr.Format = FormatUnknown // Non-ASCII characters in block.
			}
			nul := func(b []byte) bool { return int(b[len(b)-1]) == 0 }

	MOVF.NE	(g), F3                                   // 003a9a1d
	MOVD	(g), F3                                   // 003b9aed
	MOVF	0x20(R3), F9       // MOVF 32(R3), F9     // 089a93ed
	MOVD.EQ	0x20(R4), F9       // MOVD.EQ 32(R4), F9  // 089b940d
	MOVF.NE	-0x20(g), F3       // MOVF.NE -32(g), F3  // 083a1a1d
	MOVD	-0x20(g), F3       // MOVD -32(g), F3     // 083b1aed
	MOVF	F9, (R4)                                  // 009a84ed

	MOVHU	R3, 0x20(R4)         // MOVHU R3, 32(R4)          // b032c4e1
	MOVHU.W	R3, 0x20(R4)         // MOVHU.W R3, 32(R4)        // b032e4e1
	MOVHU.P	R3, 0x20(R4)         // MOVHU.P R3, 32(R4)        // b032c4e0
	MOVH	R3, -0x20(R4)        // MOVH R3, -32(R4)          // b03244e1
	MOVH.W	R3, -0x20(R4)        // MOVH.W R3, -32(R4)        // b03264e1
	MOVH.P	R3, -0x20(R4)        // MOVH.P R3, -32(R4)        // b03244e0

			Devminor: 0,
			Format:   FormatGNU,
		}, {
			Name:     "sparse-posix-0.0",
			Mode:     420,
			Uid:      1000,
			Gid:      1000,
			Size:     200,
			ModTime:  time.Unix(1392342187, 0),
			Typeflag: 0x30,
			Linkname: "",
			Uname:    "david",
			Gname:    "david",
			Devmajor: 0,
			Devminor: 0,
			PAXRecords: map[string]string{
				"GNU.sparse.size":      "200",
				"GNU.sparse.numblocks": "95",

	MOVD	$0xffffff(R7), R1             // MOVD	$16777215(R7), R1           // e1fc7f9121fc3f91
	MOVD	$-0x1(R7), R1                 // MOVD	$-1(R7), R1                 // e10400d1
	MOVD	$-0x30(R7), R1                // MOVD	$-48(R7), R1                // e1c000d1
	MOVD	$-0x708(R7), R1               // MOVD	$-1800(R7), R1              // e1201cd1

	utf8Valid1, utf8Require1 := detectUTF8(fh.Name)
	utf8Valid2, utf8Require2 := detectUTF8(fh.Comment)
	switch {
	case fh.NonUTF8:
		fh.Flags &^= 0x800
	case (utf8Require1 || utf8Require2) && (utf8Valid1 && utf8Valid2):
		fh.Flags |= 0x800
	}

	fh.CreatorVersion = fh.CreatorVersion&0xff00 | zipVersion20 // preserve compatibility byte
	fh.ReaderVersion = zipVersion20