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65<p>
66Next: <a href="Loc_005fmark_005flabels.html#Loc_005fmark_005flabels" accesskey="n" rel="next">Loc_mark_labels</a>, Previous: <a href="Ln.html#Ln" accesskey="p" rel="previous">Ln</a>, Up: <a href="Pseudo-Ops.html#Pseudo-Ops" accesskey="u" rel="up">Pseudo Ops</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="AS-Index.html#AS-Index" title="Index" rel="index">Index</a>]</p>
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69<a name="g_t_002eloc-fileno-lineno-_005bcolumn_005d-_005boptions_005d"></a>
70<h3 class="section">7.58 <code>.loc <var>fileno</var> <var>lineno</var> [<var>column</var>] [<var>options</var>]</code></h3>
71<a name="index-loc-directive"></a>
72<p>When emitting DWARF2 line number information,
73the <code>.loc</code> directive will add a row to the <code>.debug_line</code> line
74number matrix corresponding to the immediately following assembly
75instruction.  The <var>fileno</var>, <var>lineno</var>, and optional <var>column</var>
76arguments will be applied to the <code>.debug_line</code> state machine before
77the row is added.  It is an error for the input assembly file to generate
78a non-empty <code>.debug_line</code> and also use <code>loc</code> directives.
79</p>
80<p>The <var>options</var> are a sequence of the following tokens in any order:
81</p>
82<dl compact="compact">
83<dt><code>basic_block</code></dt>
84<dd><p>This option will set the <code>basic_block</code> register in the
85<code>.debug_line</code> state machine to <code>true</code>.
86</p>
87</dd>
88<dt><code>prologue_end</code></dt>
89<dd><p>This option will set the <code>prologue_end</code> register in the
90<code>.debug_line</code> state machine to <code>true</code>.
91</p>
92</dd>
93<dt><code>epilogue_begin</code></dt>
94<dd><p>This option will set the <code>epilogue_begin</code> register in the
95<code>.debug_line</code> state machine to <code>true</code>.
96</p>
97</dd>
98<dt><code>is_stmt <var>value</var></code></dt>
99<dd><p>This option will set the <code>is_stmt</code> register in the
100<code>.debug_line</code> state machine to <code>value</code>, which must be
101either 0 or 1.
102</p>
103</dd>
104<dt><code>isa <var>value</var></code></dt>
105<dd><p>This directive will set the <code>isa</code> register in the <code>.debug_line</code>
106state machine to <var>value</var>, which must be an unsigned integer.
107</p>
108</dd>
109<dt><code>discriminator <var>value</var></code></dt>
110<dd><p>This directive will set the <code>discriminator</code> register in the <code>.debug_line</code>
111state machine to <var>value</var>, which must be an unsigned integer.
112</p>
113</dd>
114<dt><code>view <var>value</var></code></dt>
115<dd><p>This option causes a row to be added to <code>.debug_line</code> in reference to the
116current address (which might not be the same as that of the following assembly
117instruction), and to associate <var>value</var> with the <code>view</code> register in the
118<code>.debug_line</code> state machine.  If <var>value</var> is a label, both the
119<code>view</code> register and the label are set to the number of prior <code>.loc</code>
120directives at the same program location.  If <var>value</var> is the literal
121<code>0</code>, the <code>view</code> register is set to zero, and the assembler asserts
122that there aren&rsquo;t any prior <code>.loc</code> directives at the same program
123location.  If <var>value</var> is the literal <code>-0</code>, the assembler arrange for
124the <code>view</code> register to be reset in this row, even if there are prior
125<code>.loc</code> directives at the same program location.
126</p>
127</dd>
128</dl>
129
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