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  64. Next: <a href="PRU-Pragmas.html#PRU-Pragmas" accesskey="n" rel="next">PRU Pragmas</a>, Previous: <a href="M32C-Pragmas.html#M32C-Pragmas" accesskey="p" rel="prev">M32C Pragmas</a>, Up: <a href="Pragmas.html#Pragmas" accesskey="u" rel="up">Pragmas</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Option-Index.html#Option-Index" title="Index" rel="index">Index</a>]</p>
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  67. <a name="MeP-Pragmas-1"></a>
  68. <h4 class="subsection">6.62.4 MeP Pragmas</h4>
  69. <dl compact="compact">
  70. <dt><code>custom io_volatile (on|off)</code></dt>
  71. <dd><a name="index-pragma_002c-custom-io_005fvolatile"></a>
  72. <p>Overrides the command-line option <code>-mio-volatile</code> for the current
  73. file. Note that for compatibility with future GCC releases, this
  74. option should only be used once before any <code>io</code> variables in each
  75. file.
  76. </p>
  77. </dd>
  78. <dt><code>GCC coprocessor available <var>registers</var></code></dt>
  79. <dd><a name="index-pragma_002c-coprocessor-available"></a>
  80. <p>Specifies which coprocessor registers are available to the register
  81. allocator. <var>registers</var> may be a single register, register range
  82. separated by ellipses, or comma-separated list of those. Example:
  83. </p>
  84. <div class="smallexample">
  85. <pre class="smallexample">#pragma GCC coprocessor available $c0...$c10, $c28
  86. </pre></div>
  87. </dd>
  88. <dt><code>GCC coprocessor call_saved <var>registers</var></code></dt>
  89. <dd><a name="index-pragma_002c-coprocessor-call_005fsaved"></a>
  90. <p>Specifies which coprocessor registers are to be saved and restored by
  91. any function using them. <var>registers</var> may be a single register,
  92. register range separated by ellipses, or comma-separated list of
  93. those. Example:
  94. </p>
  95. <div class="smallexample">
  96. <pre class="smallexample">#pragma GCC coprocessor call_saved $c4...$c6, $c31
  97. </pre></div>
  98. </dd>
  99. <dt><code>GCC coprocessor subclass '(A|B|C|D)' = <var>registers</var></code></dt>
  100. <dd><a name="index-pragma_002c-coprocessor-subclass"></a>
  101. <p>Creates and defines a register class. These register classes can be
  102. used by inline <code>asm</code> constructs. <var>registers</var> may be a single
  103. register, register range separated by ellipses, or comma-separated
  104. list of those. Example:
  105. </p>
  106. <div class="smallexample">
  107. <pre class="smallexample">#pragma GCC coprocessor subclass 'B' = $c2, $c4, $c6
  108. asm (&quot;cpfoo %0&quot; : &quot;=B&quot; (x));
  109. </pre></div>
  110. </dd>
  111. <dt><code>GCC disinterrupt <var>name</var> , <var>name</var> &hellip;</code></dt>
  112. <dd><a name="index-pragma_002c-disinterrupt"></a>
  113. <p>For the named functions, the compiler adds code to disable interrupts
  114. for the duration of those functions. If any functions so named
  115. are not encountered in the source, a warning is emitted that the pragma is
  116. not used. Examples:
  117. </p>
  118. <div class="smallexample">
  119. <pre class="smallexample">#pragma disinterrupt foo
  120. #pragma disinterrupt bar, grill
  121. int foo () { &hellip; }
  122. </pre></div>
  123. </dd>
  124. <dt><code>GCC call <var>name</var> , <var>name</var> &hellip;</code></dt>
  125. <dd><a name="index-pragma_002c-call"></a>
  126. <p>For the named functions, the compiler always uses a register-indirect
  127. call model when calling the named functions. Examples:
  128. </p>
  129. <div class="smallexample">
  130. <pre class="smallexample">extern int foo ();
  131. #pragma call foo
  132. </pre></div>
  133. </dd>
  134. </dl>
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