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https://gitlab.com/infected_/linaro_aarch64-linux-gnu-4.9.x
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  16. <title>Using as: M</title>
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  63. <a name="M"></a>
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  64. <div class="header">
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  65. <p>
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  66. Next: <a href="MD.html#MD" accesskey="n" rel="next">MD</a>, Previous: <a href="listing.html#listing" accesskey="p" rel="prev">listing</a>, Up: <a href="Invoking.html#Invoking" accesskey="u" rel="up">Invoking</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>
    67. 

  67. </div>
    68. 

  68. <hr>
    69. 

  69. <a name="Assemble-in-MRI-Compatibility-Mode_003a-_002dM"></a>
    70. 

  70. <h3 class="section">2.9 Assemble in MRI Compatibility Mode: <samp>-M</samp></h3>
    71. 

  71. 

  72. <a name="index-_002dM"></a>
    73. 

  73. <a name="index-MRI-compatibility-mode"></a>
    74. 

  74. <p>The <samp>-M</samp> or <samp>--mri</samp> option selects MRI compatibility mode.  This
    75. 

  75. changes the syntax and pseudo-op handling of <code>as</code> to make it
    76. 

  76. compatible with the <code>ASM68K</code> or the <code>ASM960</code> (depending upon the
    77. 

  77. configured target) assembler from Microtec Research.  The exact nature of the
    78. 

  78. MRI syntax will not be documented here; see the MRI manuals for more
    79. 

  79. information.  Note in particular that the handling of macros and macro
    80. 

  80. arguments is somewhat different.  The purpose of this option is to permit
    81. 

  81. assembling existing MRI assembler code using <code>as</code>.
    82. 

  82. </p>
    83. 

  83. <p>The MRI compatibility is not complete.  Certain operations of the MRI assembler
    84. 

  84. depend upon its object file format, and can not be supported using other object
    85. 

  85. file formats.  Supporting these would require enhancing each object file format
    86. 

  86. individually.  These are:
    87. 

  87. </p>
    88. 

  88. <ul>
    89. 

  89. <li> global symbols in common section
    90. 

  90. 

  91. <p>The m68k MRI assembler supports common sections which are merged by the linker.
    92. 

  92. Other object file formats do not support this.  <code>as</code> handles
    93. 

  93. common sections by treating them as a single common symbol.  It permits local
    94. 

  94. symbols to be defined within a common section, but it can not support global
    95. 

  95. symbols, since it has no way to describe them.
    96. 

  96. </p>
    97. 

  97. </li><li> complex relocations
    98. 

  98. 

  99. <p>The MRI assemblers support relocations against a negated section address, and
    100. 

  100. relocations which combine the start addresses of two or more sections.  These
    101. 

  101. are not support by other object file formats.
    102. 

  102. </p>
    103. 

  103. </li><li> <code>END</code> pseudo-op specifying start address
    104. 

  104. 

  105. <p>The MRI <code>END</code> pseudo-op permits the specification of a start address.
    106. 

  106. This is not supported by other object file formats.  The start address may
    107. 

  107. instead be specified using the <samp>-e</samp> option to the linker, or in a linker
    108. 

  108. script.
    109. 

  109. </p>
    110. 

  110. </li><li> <code>IDNT</code>, <code>.ident</code> and <code>NAME</code> pseudo-ops
    111. 

  111. 

  112. <p>The MRI <code>IDNT</code>, <code>.ident</code> and <code>NAME</code> pseudo-ops assign a module
    113. 

  113. name to the output file.  This is not supported by other object file formats.
    114. 

  114. </p>
    115. 

  115. </li><li> <code>ORG</code> pseudo-op
    116. 

  116. 

  117. <p>The m68k MRI <code>ORG</code> pseudo-op begins an absolute section at a given
    118. 

  118. address.  This differs from the usual <code>as</code> <code>.org</code> pseudo-op,
    119. 

  119. which changes the location within the current section.  Absolute sections are
    120. 

  120. not supported by other object file formats.  The address of a section may be
    121. 

  121. assigned within a linker script.
    122. 

  122. </p></li></ul>
    123. 

  123. 

  124. <p>There are some other features of the MRI assembler which are not supported by
    125. 

  125. <code>as</code>, typically either because they are difficult or because they
    126. 

  126. seem of little consequence.  Some of these may be supported in future releases.
    127. 

  127. </p>
    128. 

  128. <ul>
    129. 

  129. <li> EBCDIC strings
    130. 

  130. 

  131. <p>EBCDIC strings are not supported.
    132. 

  132. </p>
    133. 

  133. </li><li> packed binary coded decimal
    134. 

  134. 

  135. <p>Packed binary coded decimal is not supported.  This means that the <code>DC.P</code>
    136. 

  136. and <code>DCB.P</code> pseudo-ops are not supported.
    137. 

  137. </p>
    138. 

  138. </li><li> <code>FEQU</code> pseudo-op
    139. 

  139. 

  140. <p>The m68k <code>FEQU</code> pseudo-op is not supported.
    141. 

  141. </p>
    142. 

  142. </li><li> <code>NOOBJ</code> pseudo-op
    143. 

  143. 

  144. <p>The m68k <code>NOOBJ</code> pseudo-op is not supported.
    145. 

  145. </p>
    146. 

  146. </li><li> <code>OPT</code> branch control options
    147. 

  147. 

  148. <p>The m68k <code>OPT</code> branch control options&mdash;<code>B</code>, <code>BRS</code>, <code>BRB</code>,
    149. 

  149. <code>BRL</code>, and <code>BRW</code>&mdash;are ignored.  <code>as</code> automatically
    150. 

  150. relaxes all branches, whether forward or backward, to an appropriate size, so
    151. 

  151. these options serve no purpose.
    152. 

  152. </p>
    153. 

  153. </li><li> <code>OPT</code> list control options
    154. 

  154. 

  155. <p>The following m68k <code>OPT</code> list control options are ignored: <code>C</code>,
    156. 

  156. <code>CEX</code>, <code>CL</code>, <code>CRE</code>, <code>E</code>, <code>G</code>, <code>I</code>, <code>M</code>,
    157. 

  157. <code>MEX</code>, <code>MC</code>, <code>MD</code>, <code>X</code>.
    158. 

  158. </p>
    159. 

  159. </li><li> other <code>OPT</code> options
    160. 

  160. 

  161. <p>The following m68k <code>OPT</code> options are ignored: <code>NEST</code>, <code>O</code>,
    162. 

  162. <code>OLD</code>, <code>OP</code>, <code>P</code>, <code>PCO</code>, <code>PCR</code>, <code>PCS</code>, <code>R</code>.
    163. 

  163. </p>
    164. 

  164. </li><li> <code>OPT</code> <code>D</code> option is default
    165. 

  165. 

  166. <p>The m68k <code>OPT</code> <code>D</code> option is the default, unlike the MRI assembler.
    167. 

  167. <code>OPT NOD</code> may be used to turn it off.
    168. 

  168. </p>
    169. 

  169. </li><li> <code>XREF</code> pseudo-op.
    170. 

  170. 

  171. <p>The m68k <code>XREF</code> pseudo-op is ignored.
    172. 

  172. </p>
    173. 

  173. </li><li> <code>.debug</code> pseudo-op
    174. 

  174. 

  175. <p>The i960 <code>.debug</code> pseudo-op is not supported.
    176. 

  176. </p>
    177. 

  177. </li><li> <code>.extended</code> pseudo-op
    178. 

  178. 

  179. <p>The i960 <code>.extended</code> pseudo-op is not supported.
    180. 

  180. </p>
    181. 

  181. </li><li> <code>.list</code> pseudo-op.
    182. 

  182. 

  183. <p>The various options of the i960 <code>.list</code> pseudo-op are not supported.
    184. 

  184. </p>
    185. 

  185. </li><li> <code>.optimize</code> pseudo-op
    186. 

  186. 

  187. <p>The i960 <code>.optimize</code> pseudo-op is not supported.
    188. 

  188. </p>
    189. 

  189. </li><li> <code>.output</code> pseudo-op
    190. 

  190. 

  191. <p>The i960 <code>.output</code> pseudo-op is not supported.
    192. 

  192. </p>
    193. 

  193. </li><li> <code>.setreal</code> pseudo-op
    194. 

  194. 

  195. <p>The i960 <code>.setreal</code> pseudo-op is not supported.
    196. 

  196. </p>
    197. 

  197. </li></ul>
    198. 

  198. 

  199. <hr>
    200. 

  200. <div class="header">
    201. 

  201. <p>
    202. 

  202. Next: <a href="MD.html#MD" accesskey="n" rel="next">MD</a>, Previous: <a href="listing.html#listing" accesskey="p" rel="prev">listing</a>, Up: <a href="Invoking.html#Invoking" accesskey="u" rel="up">Invoking</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>
    203. 

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    204. 

  204. 

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    209. 

  209.