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. Buying copies from GNU Press supports the FSF in 14developing GNU and promoting software freedom." --> 15<!-- Created by GNU Texinfo 5.1, http://www.gnu.org/software/texinfo/ --> 16<head> 17<title>Debugging with GDB: Varying Target Capabilities</title> 18 19<meta name="description" content="Debugging with GDB: Varying Target Capabilities"> 20<meta name="keywords" content="Debugging with GDB: Varying Target Capabilities"> 21<meta name="resource-type" content="document"> 22<meta name="distribution" content="global"> 23<meta name="Generator" content="makeinfo"> 24<meta http-equiv="Content-Type" content="text/html; charset=utf-8"> 25<link href="index.html#Top" rel="start" title="Top"> 26<link href="Concept-Index.html#Concept-Index" rel="index" title="Concept Index"> 27<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents"> 28<link href="Agent-Expressions.html#Agent-Expressions" rel="up" title="Agent Expressions"> 29<link href="Rationale.html#Rationale" rel="next" title="Rationale"> 30<link href="Using-Agent-Expressions.html#Using-Agent-Expressions" rel="previous" title="Using Agent Expressions"> 31<style type="text/css"> 32<!-- 33a.summary-letter {text-decoration: none} 34blockquote.smallquotation {font-size: smaller} 35div.display {margin-left: 3.2em} 36div.example {margin-left: 3.2em} 37div.indentedblock {margin-left: 3.2em} 38div.lisp {margin-left: 3.2em} 39div.smalldisplay {margin-left: 3.2em} 40div.smallexample {margin-left: 3.2em} 41div.smallindentedblock {margin-left: 3.2em; font-size: smaller} 42div.smalllisp {margin-left: 3.2em} 43kbd {font-style:oblique} 44pre.display {font-family: inherit} 45pre.format {font-family: inherit} 46pre.menu-comment {font-family: serif} 47pre.menu-preformatted {font-family: serif} 48pre.smalldisplay {font-family: inherit; font-size: smaller} 49pre.smallexample {font-size: smaller} 50pre.smallformat {font-family: inherit; font-size: smaller} 51pre.smalllisp {font-size: smaller} 52span.nocodebreak {white-space:nowrap} 53span.nolinebreak {white-space:nowrap} 54span.roman {font-family:serif; font-weight:normal} 55span.sansserif {font-family:sans-serif; font-weight:normal} 56ul.no-bullet {list-style: none} 57--> 58</style> 59 60 61</head> 62 63<body lang="en" bgcolor="#FFFFFF" text="#000000" link="#0000FF" vlink="#800080" alink="#FF0000"> 64<a name="Varying-Target-Capabilities"></a> 65<div class="header"> 66<p> 67Next: <a href="Rationale.html#Rationale" accesskey="n" rel="next">Rationale</a>, Previous: <a href="Using-Agent-Expressions.html#Using-Agent-Expressions" accesskey="p" rel="previous">Using Agent Expressions</a>, Up: <a href="Agent-Expressions.html#Agent-Expressions" accesskey="u" rel="up">Agent Expressions</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> 68</div> 69<hr> 70<a name="Varying-Target-Capabilities-1"></a> 71<h3 class="section">F.4 Varying Target Capabilities</h3> 72 73<p>Some targets don’t support floating-point, and some would rather not 74have to deal with <code>long long</code> operations. Also, different targets 75will have different stack sizes, and different bytecode buffer lengths. 76</p> 77<p>Thus, GDB needs a way to ask the target about itself. We haven’t worked 78out the details yet, but in general, GDB should be able to send the 79target a packet asking it to describe itself. The reply should be a 80packet whose length is explicit, so we can add new information to the 81packet in future revisions of the agent, without confusing old versions 82of GDB, and it should contain a version number. It should contain at 83least the following information: 84</p> 85<ul> 86<li> whether floating point is supported 87 88</li><li> whether <code>long long</code> is supported 89 90</li><li> maximum acceptable size of bytecode stack 91 92</li><li> maximum acceptable length of bytecode expressions 93 94</li><li> which registers are actually available for collection 95 96</li><li> whether the target supports disabled tracepoints 97 98</li></ul> 99 100 101 102 103</body> 104</html> 105