MIPS-insn.html 4.5 KB

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109
  1. <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
  2. <html>
  3. <!-- This file documents the GNU Assembler "as".
  4. Copyright (C) 1991-2017 Free Software Foundation, Inc.
  5. Permission is granted to copy, distribute and/or modify this document
  6. under the terms of the GNU Free Documentation License, Version 1.3
  7. or any later version published by the Free Software Foundation;
  8. with no Invariant Sections, with no Front-Cover Texts, and with no
  9. Back-Cover Texts. A copy of the license is included in the
  10. section entitled "GNU Free Documentation License".
  11. -->
  12. <!-- Created by GNU Texinfo 5.2, http://www.gnu.org/software/texinfo/ -->
  13. <head>
  14. <title>Using as: MIPS insn</title>
  15. <meta name="description" content="Using as: MIPS insn">
  16. <meta name="keywords" content="Using as: MIPS insn">
  17. <meta name="resource-type" content="document">
  18. <meta name="distribution" content="global">
  19. <meta name="Generator" content="makeinfo">
  20. <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
  21. <link href="index.html#Top" rel="start" title="Top">
  22. <link href="AS-Index.html#AS-Index" rel="index" title="AS Index">
  23. <link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
  24. <link href="MIPS_002dDependent.html#MIPS_002dDependent" rel="up" title="MIPS-Dependent">
  25. <link href="MIPS-FP-ABIs.html#MIPS-FP-ABIs" rel="next" title="MIPS FP ABIs">
  26. <link href="MIPS-autoextend.html#MIPS-autoextend" rel="prev" title="MIPS autoextend">
  27. <style type="text/css">
  28. <!--
  29. a.summary-letter {text-decoration: none}
  30. blockquote.smallquotation {font-size: smaller}
  31. div.display {margin-left: 3.2em}
  32. div.example {margin-left: 3.2em}
  33. div.indentedblock {margin-left: 3.2em}
  34. div.lisp {margin-left: 3.2em}
  35. div.smalldisplay {margin-left: 3.2em}
  36. div.smallexample {margin-left: 3.2em}
  37. div.smallindentedblock {margin-left: 3.2em; font-size: smaller}
  38. div.smalllisp {margin-left: 3.2em}
  39. kbd {font-style:oblique}
  40. pre.display {font-family: inherit}
  41. pre.format {font-family: inherit}
  42. pre.menu-comment {font-family: serif}
  43. pre.menu-preformatted {font-family: serif}
  44. pre.smalldisplay {font-family: inherit; font-size: smaller}
  45. pre.smallexample {font-size: smaller}
  46. pre.smallformat {font-family: inherit; font-size: smaller}
  47. pre.smalllisp {font-size: smaller}
  48. span.nocodebreak {white-space:nowrap}
  49. span.nolinebreak {white-space:nowrap}
  50. span.roman {font-family:serif; font-weight:normal}
  51. span.sansserif {font-family:sans-serif; font-weight:normal}
  52. ul.no-bullet {list-style: none}
  53. -->
  54. </style>
  55. </head>
  56. <body lang="en" bgcolor="#FFFFFF" text="#000000" link="#0000FF" vlink="#800080" alink="#FF0000">
  57. <a name="MIPS-insn"></a>
  58. <div class="header">
  59. <p>
  60. Next: <a href="MIPS-FP-ABIs.html#MIPS-FP-ABIs" accesskey="n" rel="next">MIPS FP ABIs</a>, Previous: <a href="MIPS-autoextend.html#MIPS-autoextend" accesskey="p" rel="prev">MIPS autoextend</a>, Up: <a href="MIPS_002dDependent.html#MIPS_002dDependent" accesskey="u" rel="up">MIPS-Dependent</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>
  61. </div>
  62. <hr>
  63. <a name="Directive-to-mark-data-as-an-instruction"></a>
  64. <h4 class="subsection">9.27.8 Directive to mark data as an instruction</h4>
  65. <a name="index-_002einsn"></a>
  66. <p>The <code>.insn</code> directive tells <code>as</code> that the following
  67. data is actually instructions. This makes a difference in MIPS 16 and
  68. microMIPS modes: when loading the address of a label which precedes
  69. instructions, <code>as</code> automatically adds 1 to the value, so
  70. that jumping to the loaded address will do the right thing.
  71. </p>
  72. <a name="index-_002eglobal"></a>
  73. <p>The <code>.global</code> and <code>.globl</code> directives supported by
  74. <code>as</code> will by default mark the symbol as pointing to a
  75. region of data not code. This means that, for example, any
  76. instructions following such a symbol will not be disassembled by
  77. <code>objdump</code> as it will regard them as data. To change this
  78. behavior an optional section name can be placed after the symbol name
  79. in the <code>.global</code> directive. If this section exists and is known
  80. to be a code section, then the symbol will be marked as pointing at
  81. code not data. Ie the syntax for the directive is:
  82. </p>
  83. <p><code>.global <var>symbol</var>[ <var>section</var>][, <var>symbol</var>[ <var>section</var>]] ...</code>,
  84. </p>
  85. <p>Here is a short example:
  86. </p>
  87. <div class="example">
  88. <pre class="example"> .global foo .text, bar, baz .data
  89. foo:
  90. nop
  91. bar:
  92. .word 0x0
  93. baz:
  94. .word 0x1
  95. </pre></div>
  96. </body>
  97. </html>