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 }

0106          ; mapped                 ; 0107          # 1.1  LATIN CAPITAL LETTER C WITH ACUTE
0107          ; valid                                  # 1.1  LATIN SMALL LETTER C WITH ACUTE
0108          ; mapped                 ; 0109          # 1.1  LATIN CAPITAL LETTER C WITH CIRCUMFLEX
0109          ; valid                                  # 1.1  LATIN SMALL LETTER C WITH CIRCUMFLEX

	INSW                                    // 666d
	//TODO: INT $3                          // cc
	INT $7                                  // cd07
	INVD                                    // 0f08
	INVLPG (BX)                             // 0f013b
	INVLPG (R11)                            // 410f013b
	INVPCID (BX), DX                        // 660f388213
	INVPCID (R11), DX                       // 66410f388213

</p>

<p>
After a backslash, certain single-character escapes represent special values:
</p>

<pre class="grammar">
\a   U+0007 alert or bell
\b   U+0008 backspace
\f   U+000C form feed
\n   U+000A line feed or newline
\r   U+000D carriage return
\t   U+0009 horizontal tab
\v   U+000B vertical tab
\\   U+005C backslash