1<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> 2<html> 3<!-- Copyright (C) 1988-2021 Free Software Foundation, Inc. 4 5Permission is granted to copy, distribute and/or modify this document 6under the terms of the GNU Free Documentation License, Version 1.3 or 7any later version published by the Free Software Foundation; with the 8Invariant Sections being "Free Software" and "Free Software Needs 9Free Documentation", with the Front-Cover Texts being "A GNU Manual," 10and with the Back-Cover Texts as in (a) below. 11 12(a) The FSF's Back-Cover Text is: "You are free to copy and modify 13this GNU Manual. 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Normally, you can simply allow 79these subroutines to communicate, and ignore the details. (If you’re 80implementing your own stub file, you can still ignore the details: start 81with one of the existing stub files. <samp>sparc-stub.c</samp> is the best 82organized, and therefore the easiest to read.) 83</p> 84<a name="index-remote-serial-debugging_002c-overview"></a> 85<p>To debug a program running on another machine (the debugging 86<em>target</em> machine), you must first arrange for all the usual 87prerequisites for the program to run by itself. For example, for a C 88program, you need: 89</p> 90<ol> 91<li> A startup routine to set up the C runtime environment; these usually 92have a name like <samp>crt0</samp>. The startup routine may be supplied by 93your hardware supplier, or you may have to write your own. 94 95</li><li> A C subroutine library to support your program’s 96subroutine calls, notably managing input and output. 97 98</li><li> A way of getting your program to the other machine—for example, a 99download program. These are often supplied by the hardware 100manufacturer, but you may have to write your own from hardware 101documentation. 102</li></ol> 103 104<p>The next step is to arrange for your program to use a serial port to 105communicate with the machine where <small>GDB</small> is running (the <em>host</em> 106machine). In general terms, the scheme looks like this: 107</p> 108<dl compact="compact"> 109<dt><em>On the host,</em></dt> 110<dd><p><small>GDB</small> already understands how to use this protocol; when everything 111else is set up, you can simply use the ‘<samp>target remote</samp>’ command 112(see <a href="Targets.html#Targets">Specifying a Debugging Target</a>). 113</p> 114</dd> 115<dt><em>On the target,</em></dt> 116<dd><p>you must link with your program a few special-purpose subroutines that 117implement the <small>GDB</small> remote serial protocol. The file containing these 118subroutines is called a <em>debugging stub</em>. 119</p> 120<p>On certain remote targets, you can use an auxiliary program 121<code>gdbserver</code> instead of linking a stub into your program. 122See <a href="Server.html#Server">Using the <code>gdbserver</code> Program</a>, for details. 123</p></dd> 124</dl> 125 126<p>The debugging stub is specific to the architecture of the remote 127machine; for example, use <samp>sparc-stub.c</samp> to debug programs on 128<small>SPARC</small> boards. 129</p> 130<a name="index-remote-serial-stub-list"></a> 131<p>These working remote stubs are distributed with <small>GDB</small>: 132</p> 133<dl compact="compact"> 134<dt><code>i386-stub.c</code></dt> 135<dd><a name="index-i386_002dstub_002ec"></a> 136<a name="index-Intel"></a> 137<a name="index-i386"></a> 138<p>For Intel 386 and compatible architectures. 139</p> 140</dd> 141<dt><code>m68k-stub.c</code></dt> 142<dd><a name="index-m68k_002dstub_002ec"></a> 143<a name="index-Motorola-680x0"></a> 144<a name="index-m680x0"></a> 145<p>For Motorola 680x0 architectures. 146</p> 147</dd> 148<dt><code>sh-stub.c</code></dt> 149<dd><a name="index-sh_002dstub_002ec"></a> 150<a name="index-Renesas"></a> 151<a name="index-SH"></a> 152<p>For Renesas SH architectures. 153</p> 154</dd> 155<dt><code>sparc-stub.c</code></dt> 156<dd><a name="index-sparc_002dstub_002ec"></a> 157<a name="index-Sparc"></a> 158<p>For <small>SPARC</small> architectures. 159</p> 160</dd> 161<dt><code>sparcl-stub.c</code></dt> 162<dd><a name="index-sparcl_002dstub_002ec"></a> 163<a name="index-Fujitsu"></a> 164<a name="index-SparcLite"></a> 165<p>For Fujitsu <small>SPARCLITE</small> architectures. 166</p> 167</dd> 168</dl> 169 170<p>The <samp>README</samp> file in the <small>GDB</small> distribution may list other 171recently added stubs. 172</p> 173<table class="menu" border="0" cellspacing="0"> 174<tr><td align="left" valign="top">• <a href="Stub-Contents.html#Stub-Contents" accesskey="1">Stub Contents</a>:</td><td> </td><td align="left" valign="top">What the stub can do for you 175</td></tr> 176<tr><td align="left" valign="top">• <a href="Bootstrapping.html#Bootstrapping" accesskey="2">Bootstrapping</a>:</td><td> </td><td align="left" valign="top">What you must do for the stub 177</td></tr> 178<tr><td align="left" valign="top">• <a href="Debug-Session.html#Debug-Session" accesskey="3">Debug Session</a>:</td><td> </td><td align="left" valign="top">Putting it all together 179</td></tr> 180</table> 181 182<hr> 183<div class="header"> 184<p> 185Previous: <a href="Remote-Configuration.html#Remote-Configuration" accesskey="p" rel="previous">Remote Configuration</a>, Up: <a href="Remote-Debugging.html#Remote-Debugging" accesskey="u" rel="up">Remote Debugging</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> 186</div> 187 188 189 190</body> 191</html> 192