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| Previous: <a rel="previous" accesskey="p" href="Remote-Configuration.html#Remote-Configuration">Remote Configuration</a>, |
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| <h3 class="section">20.5 Implementing a Remote Stub</h3> |
| |
| <p><a name="index-debugging-stub_002c-example-1405"></a><a name="index-remote-stub_002c-example-1406"></a><a name="index-stub-example_002c-remote-debugging-1407"></a>The stub files provided with <span class="sc">gdb</span> implement the target side of the |
| communication protocol, and the <span class="sc">gdb</span> side is implemented in the |
| <span class="sc">gdb</span> source file <samp><span class="file">remote.c</span></samp>. Normally, you can simply allow |
| these subroutines to communicate, and ignore the details. (If you're |
| implementing your own stub file, you can still ignore the details: start |
| with one of the existing stub files. <samp><span class="file">sparc-stub.c</span></samp> is the best |
| organized, and therefore the easiest to read.) |
| |
| <p><a name="index-remote-serial-debugging_002c-overview-1408"></a>To debug a program running on another machine (the debugging |
| <dfn>target</dfn> machine), you must first arrange for all the usual |
| prerequisites for the program to run by itself. For example, for a C |
| program, you need: |
| |
| <ol type=1 start=1> |
| <li>A startup routine to set up the C runtime environment; these usually |
| have a name like <samp><span class="file">crt0</span></samp>. The startup routine may be supplied by |
| your hardware supplier, or you may have to write your own. |
| |
| <li>A C subroutine library to support your program's |
| subroutine calls, notably managing input and output. |
| |
| <li>A way of getting your program to the other machine—for example, a |
| download program. These are often supplied by the hardware |
| manufacturer, but you may have to write your own from hardware |
| documentation. |
| </ol> |
| |
| <p>The next step is to arrange for your program to use a serial port to |
| communicate with the machine where <span class="sc">gdb</span> is running (the <dfn>host</dfn> |
| machine). In general terms, the scheme looks like this: |
| |
| <dl> |
| <dt><em>On the host,</em><dd><span class="sc">gdb</span> already understands how to use this protocol; when everything |
| else is set up, you can simply use the ‘<samp><span class="samp">target remote</span></samp>’ command |
| (see <a href="Targets.html#Targets">Specifying a Debugging Target</a>). |
| |
| <br><dt><em>On the target,</em><dd>you must link with your program a few special-purpose subroutines that |
| implement the <span class="sc">gdb</span> remote serial protocol. The file containing these |
| subroutines is called a <dfn>debugging stub</dfn>. |
| |
| <p>On certain remote targets, you can use an auxiliary program |
| <code>gdbserver</code> instead of linking a stub into your program. |
| See <a href="Server.html#Server">Using the <code>gdbserver</code> Program</a>, for details. |
| </dl> |
| |
| <p>The debugging stub is specific to the architecture of the remote |
| machine; for example, use <samp><span class="file">sparc-stub.c</span></samp> to debug programs on |
| <span class="sc">sparc</span> boards. |
| |
| <p><a name="index-remote-serial-stub-list-1409"></a>These working remote stubs are distributed with <span class="sc">gdb</span>: |
| |
| <dl> |
| <dt><code>i386-stub.c</code><dd><a name="index-g_t_0040file_007bi386_002dstub_002ec_007d-1410"></a><a name="index-Intel-1411"></a><a name="index-i386-1412"></a>For Intel 386 and compatible architectures. |
| |
| <br><dt><code>m68k-stub.c</code><dd><a name="index-g_t_0040file_007bm68k_002dstub_002ec_007d-1413"></a><a name="index-Motorola-680x0-1414"></a><a name="index-m680x0-1415"></a>For Motorola 680x0 architectures. |
| |
| <br><dt><code>sh-stub.c</code><dd><a name="index-g_t_0040file_007bsh_002dstub_002ec_007d-1416"></a><a name="index-Renesas-1417"></a><a name="index-SH-1418"></a>For Renesas SH architectures. |
| |
| <br><dt><code>sparc-stub.c</code><dd><a name="index-g_t_0040file_007bsparc_002dstub_002ec_007d-1419"></a><a name="index-Sparc-1420"></a>For <span class="sc">sparc</span> architectures. |
| |
| <br><dt><code>sparcl-stub.c</code><dd><a name="index-g_t_0040file_007bsparcl_002dstub_002ec_007d-1421"></a><a name="index-Fujitsu-1422"></a><a name="index-SparcLite-1423"></a>For Fujitsu <span class="sc">sparclite</span> architectures. |
| |
| </dl> |
| |
| <p>The <samp><span class="file">README</span></samp> file in the <span class="sc">gdb</span> distribution may list other |
| recently added stubs. |
| |
| <ul class="menu"> |
| <li><a accesskey="1" href="Stub-Contents.html#Stub-Contents">Stub Contents</a>: What the stub can do for you |
| <li><a accesskey="2" href="Bootstrapping.html#Bootstrapping">Bootstrapping</a>: What you must do for the stub |
| <li><a accesskey="3" href="Debug-Session.html#Debug-Session">Debug Session</a>: Putting it all together |
| </ul> |
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