You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.

121 lines
4.8KB

  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) 1991-2020 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 6.5, http://www.gnu.org/software/texinfo/ -->
  13. <head>
  14. <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
  15. <title>AArch64-Relocations (Using as)</title>
  16. <meta name="description" content="AArch64-Relocations (Using as)">
  17. <meta name="keywords" content="AArch64-Relocations (Using as)">
  18. <meta name="resource-type" content="document">
  19. <meta name="distribution" content="global">
  20. <meta name="Generator" content="makeinfo">
  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="AArch64-Syntax.html#AArch64-Syntax" rel="up" title="AArch64 Syntax">
  25. <link href="AArch64-Floating-Point.html#AArch64-Floating-Point" rel="next" title="AArch64 Floating Point">
  26. <link href="AArch64_002dRegs.html#AArch64_002dRegs" rel="prev" title="AArch64-Regs">
  27. <style type="text/css">
  28. <!--
  29. a.summary-letter {text-decoration: none}
  30. blockquote.indentedblock {margin-right: 0em}
  31. blockquote.smallindentedblock {margin-right: 0em; font-size: smaller}
  32. blockquote.smallquotation {font-size: smaller}
  33. div.display {margin-left: 3.2em}
  34. div.example {margin-left: 3.2em}
  35. div.lisp {margin-left: 3.2em}
  36. div.smalldisplay {margin-left: 3.2em}
  37. div.smallexample {margin-left: 3.2em}
  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.nolinebreak {white-space: nowrap}
  49. span.roman {font-family: initial; font-weight: normal}
  50. span.sansserif {font-family: sans-serif; font-weight: normal}
  51. ul.no-bullet {list-style: none}
  52. -->
  53. </style>
  54. </head>
  55. <body lang="en">
  56. <a name="AArch64_002dRelocations"></a>
  57. <div class="header">
  58. <p>
  59. Previous: <a href="AArch64_002dRegs.html#AArch64_002dRegs" accesskey="p" rel="prev">AArch64-Regs</a>, Up: <a href="AArch64-Syntax.html#AArch64-Syntax" accesskey="u" rel="up">AArch64 Syntax</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>
  60. </div>
  61. <hr>
  62. <a name="Relocations"></a>
  63. <h4 class="subsubsection">9.1.3.3 Relocations</h4>
  64. <a name="index-relocations_002c-AArch64"></a>
  65. <a name="index-AArch64-relocations"></a>
  66. <a name="index-MOVN_002c-MOVZ-and-MOVK-group-relocations_002c-AArch64"></a>
  67. <p>Relocations for &lsquo;<samp>MOVZ</samp>&rsquo; and &lsquo;<samp>MOVK</samp>&rsquo; instructions can be generated
  68. by prefixing the label with &lsquo;<samp>#:abs_g2:</samp>&rsquo; etc.
  69. For example to load the 48-bit absolute address of <var>foo</var> into x0:
  70. </p>
  71. <div class="smallexample">
  72. <pre class="smallexample"> movz x0, #:abs_g2:foo // bits 32-47, overflow check
  73. movk x0, #:abs_g1_nc:foo // bits 16-31, no overflow check
  74. movk x0, #:abs_g0_nc:foo // bits 0-15, no overflow check
  75. </pre></div>
  76. <a name="index-ADRP_002c-ADD_002c-LDR_002fSTR-group-relocations_002c-AArch64"></a>
  77. <p>Relocations for &lsquo;<samp>ADRP</samp>&rsquo;, and &lsquo;<samp>ADD</samp>&rsquo;, &lsquo;<samp>LDR</samp>&rsquo; or &lsquo;<samp>STR</samp>&rsquo;
  78. instructions can be generated by prefixing the label with
  79. &lsquo;<samp>:pg_hi21:</samp>&rsquo; and &lsquo;<samp>#:lo12:</samp>&rsquo; respectively.
  80. </p>
  81. <p>For example to use 33-bit (+/-4GB) pc-relative addressing to
  82. load the address of <var>foo</var> into x0:
  83. </p>
  84. <div class="smallexample">
  85. <pre class="smallexample"> adrp x0, :pg_hi21:foo
  86. add x0, x0, #:lo12:foo
  87. </pre></div>
  88. <p>Or to load the value of <var>foo</var> into x0:
  89. </p>
  90. <div class="smallexample">
  91. <pre class="smallexample"> adrp x0, :pg_hi21:foo
  92. ldr x0, [x0, #:lo12:foo]
  93. </pre></div>
  94. <p>Note that &lsquo;<samp>:pg_hi21:</samp>&rsquo; is optional.
  95. </p>
  96. <div class="smallexample">
  97. <pre class="smallexample"> adrp x0, foo
  98. </pre></div>
  99. <p>is equivalent to
  100. </p>
  101. <div class="smallexample">
  102. <pre class="smallexample"> adrp x0, :pg_hi21:foo
  103. </pre></div>
  104. </body>
  105. </html>