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 <a name="Trace-File-Format"></a>
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 Next: <a href="Index-Section-Format.html#Index-Section-Format" accesskey="n" rel="next">Index Section Format</a>, Previous: <a href="Operating-System-Information.html#Operating-System-Information" accesskey="p" rel="prev">Operating System Information</a>, Up: <a href="index.html#Top" accesskey="u" rel="up">Top</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html#Concept-Index" title="Index" rel="index">Index</a>]</p>
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 <hr>
 <a name="Trace-File-Format-1"></a>
 <h2 class="appendix">Appendix I Trace File Format</h2>
 <a name="index-trace-file-format"></a>

 <p>The trace file comes in three parts: a header, a textual description
 section, and a trace frame section with binary data.
 </p>
 <p>The header has the form <code>\x7fTRACE0\n</code>.  The first byte is
 <code>0x7f</code> so as to indicate that the file contains binary data,
 while the <code>0</code> is a version number that may have different values
 in the future.
 </p>
 <p>The description section consists of multiple lines of <small>ASCII</small> text
 separated by newline characters (<code>0xa</code>).  The lines may include a
 variety of optional descriptive or context-setting information, such
 as tracepoint definitions or register set size.  <small>GDB</small> will
 ignore any line that it does not recognize.  An empty line marks the end
 of this section.
 </p>

 <p>The trace frame section consists of a number of consecutive frames.
 Each frame begins with a two-byte tracepoint number, followed by a
 four-byte size giving the amount of data in the frame.  The data in
 the frame consists of a number of blocks, each introduced by a
 character indicating its type (at least register, memory, and trace
 state variable).  The data in this section is raw binary, not a
 hexadecimal or other encoding; its endianness matches the target&rsquo;s
 endianness.
 </p>

 <dl compact="compact">
 <dt><code>R <var>bytes</var></code></dt>
 <dd><p>Register block.  The number and ordering of bytes matches that of a
 <code>g</code> packet in the remote protocol.  Note that these are the
 actual bytes, in target order and <small>GDB</small> register order, not a
 hexadecimal encoding.
 </p>
 </dd>
 <dt><code>M <var>address</var> <var>length</var> <var>bytes</var>...</code></dt>
 <dd><p>Memory block.  This is a contiguous block of memory, at the 8-byte
 address <var>address</var>, with a 2-byte length <var>length</var>, followed by
 <var>length</var> bytes.
 </p>
 </dd>
 <dt><code>V <var>number</var> <var>value</var></code></dt>
 <dd><p>Trace state variable block.  This records the 8-byte signed value
 <var>value</var> of trace state variable numbered <var>number</var>.
 </p>
 </dd>
 </dl>

 <p>Future enhancements of the trace file format may include additional types
 of blocks.
 </p>
 <hr>
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 Next: <a href="Index-Section-Format.html#Index-Section-Format" accesskey="n" rel="next">Index Section Format</a>, Previous: <a href="Operating-System-Information.html#Operating-System-Information" accesskey="p" rel="prev">Operating System Information</a>, Up: <a href="index.html#Top" accesskey="u" rel="up">Top</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html#Concept-Index" title="Index" rel="index">Index</a>]</p>
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	<a name="Trace-File-Format"></a>
	<div class="header">
	<p>
	Next: <a href="Index-Section-Format.html#Index-Section-Format" accesskey="n" rel="next">Index Section Format</a>, Previous: <a href="Operating-System-Information.html#Operating-System-Information" accesskey="p" rel="prev">Operating System Information</a>, Up: <a href="index.html#Top" accesskey="u" rel="up">Top</a>   [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html#Concept-Index" title="Index" rel="index">Index</a>]</p>
	</div>
	<hr>
	<a name="Trace-File-Format-1"></a>
	<h2 class="appendix">Appendix I Trace File Format</h2>
	<a name="index-trace-file-format"></a>

	<p>The trace file comes in three parts: a header, a textual description
	section, and a trace frame section with binary data.
	</p>
	<p>The header has the form <code>\x7fTRACE0\n</code>. The first byte is
	<code>0x7f</code> so as to indicate that the file contains binary data,
	while the <code>0</code> is a version number that may have different values
	in the future.
	</p>
	<p>The description section consists of multiple lines of <small>ASCII</small> text
	separated by newline characters (<code>0xa</code>). The lines may include a
	variety of optional descriptive or context-setting information, such
	as tracepoint definitions or register set size. <small>GDB</small> will
	ignore any line that it does not recognize. An empty line marks the end
	of this section.
	</p>

	<p>The trace frame section consists of a number of consecutive frames.
	Each frame begins with a two-byte tracepoint number, followed by a
	four-byte size giving the amount of data in the frame. The data in
	the frame consists of a number of blocks, each introduced by a
	character indicating its type (at least register, memory, and trace
	state variable). The data in this section is raw binary, not a
	hexadecimal or other encoding; its endianness matches the target’s
	endianness.
	</p>

	<dl compact="compact">
	<dt><code>R <var>bytes</var></code></dt>
	<dd><p>Register block. The number and ordering of bytes matches that of a
	<code>g</code> packet in the remote protocol. Note that these are the
	actual bytes, in target order and <small>GDB</small> register order, not a
	hexadecimal encoding.
	</p>
	</dd>
	<dt><code>M <var>address</var> <var>length</var> <var>bytes</var>...</code></dt>
	<dd><p>Memory block. This is a contiguous block of memory, at the 8-byte
	address <var>address</var>, with a 2-byte length <var>length</var>, followed by
	<var>length</var> bytes.
	</p>
	</dd>
	<dt><code>V <var>number</var> <var>value</var></code></dt>
	<dd><p>Trace state variable block. This records the 8-byte signed value
	<var>value</var> of trace state variable numbered <var>number</var>.
	</p>
	</dd>
	</dl>

	<p>Future enhancements of the trace file format may include additional types
	of blocks.
	</p>
	<hr>
	<div class="header">
	<p>
	Next: <a href="Index-Section-Format.html#Index-Section-Format" accesskey="n" rel="next">Index Section Format</a>, Previous: <a href="Operating-System-Information.html#Operating-System-Information" accesskey="p" rel="prev">Operating System Information</a>, Up: <a href="index.html#Top" accesskey="u" rel="up">Top</a>   [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html#Concept-Index" title="Index" rel="index">Index</a>]</p>
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