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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Moreover, <em>flags</em> and <em>PC</em> 76registers, which are important to <small>GDB</small>, are not “core” registers in 77ARC. Therefore, there are two features that their presence is mandatory: 78‘<samp>org.gnu.gdb.arc.core</samp>’ and ‘<samp>org.gnu.gdb.arc.aux</samp>’. 79</p> 80<p>The ‘<samp>org.gnu.gdb.arc.core</samp>’ feature is required for all targets. It must 81contain registers: 82</p> 83<ul class="no-bullet"> 84<li>- ‘<samp>r0</samp>’ through ‘<samp>r25</samp>’ for normal register file targets. 85</li><li>- ‘<samp>r0</samp>’ through ‘<samp>r3</samp>’, and ‘<samp>r10</samp>’ through ‘<samp>r15</samp>’ for reduced 86register file targets. 87</li><li>- ‘<samp>gp</samp>’, ‘<samp>fp</samp>’, ‘<samp>sp</samp>’, ‘<samp>r30</samp>’<a name="DOCF21" href="#FOOT21"><sup>21</sup></a>, 88‘<samp>blink</samp>’, ‘<samp>lp_count</samp>’, ‘<samp>pcl</samp>’. 89</li></ul> 90 91<p>In case of an ARCompact target (ARCv1 ISA), the ‘<samp>org.gnu.gdb.arc.core</samp>’ 92feature may contain registers ‘<samp>ilink1</samp>’ and ‘<samp>ilink2</samp>’. While in case 93of ARC EM and ARC HS targets (ARCv2 ISA), register ‘<samp>ilink</samp>’ may be present. 94The difference between ARCv1 and ARCv2 is the naming of registers <em>29th</em> 95and <em>30th</em>. They are called ‘<samp>ilink1</samp>’ and ‘<samp>ilink2</samp>’ for ARCv1 and 96are optional. For ARCv2, they are called ‘<samp>ilink</samp>’ and ‘<samp>r30</samp>’ and only 97‘<samp>ilink</samp>’ is optional. The optionality of ‘<samp>ilink*</samp>’ registers is 98because of their inaccessibility during user space debugging sessions. 99</p> 100<p>Extension core registers ‘<samp>r32</samp>’ through ‘<samp>r59</samp>’ are optional and their 101existence depends on the configuration. When debugging GNU/Linux applications, 102i.e. user space debugging, these core registers are not available. 103</p> 104<p>The ‘<samp>org.gnu.gdb.arc.aux</samp>’ feature is required for all ARC targets. Here 105is the list of registers pertinent to this feature: 106</p> 107<ul class="no-bullet"> 108<li>- mandatory: ‘<samp>pc</samp>’ and ‘<samp>status32</samp>’. 109</li><li>- optional: ‘<samp>lp_start</samp>’, ‘<samp>lp_end</samp>’, and ‘<samp>bta</samp>’. 110</li></ul> 111 112<div class="footnote"> 113<hr> 114<h4 class="footnotes-heading">Footnotes</h4> 115 116<h3><a name="FOOT21" href="#DOCF21">(21)</a></h3> 117<p>Not necessary for ARCv1.</p> 118</div> 119 120 121 122</body> 123</html> 124