<html lang="en"> <head> <title>AVR-Modifiers - Using as</title> <meta http-equiv="Content-Type" content="text/html"> <meta name="description" content="Using as"> <meta name="generator" content="makeinfo 4.7"> <link title="Top" rel="start" href="index.html#Top"> <link rel="up" href="AVR-Syntax.html#AVR-Syntax" title="AVR Syntax"> <link rel="prev" href="AVR_002dRegs.html#AVR_002dRegs" title="AVR-Regs"> <link href="http://www.gnu.org/software/texinfo/" rel="generator-home" title="Texinfo Homepage"> <!-- This file documents the GNU Assembler "as". Copyright (C) 1991, 92, 93, 94, 95, 96, 97, 98, 99, 2000, 2001, 2002, 2006, 2007 Free Software Foundation, Inc. Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.1 or any later version published by the Free Software Foundation; with no Invariant Sections, with no Front-Cover Texts, and with no Back-Cover Texts. A copy of the license is included in the section entitled ``GNU Free Documentation License''. man end--> <meta http-equiv="Content-Style-Type" content="text/css"> <style type="text/css"><!-- pre.display { font-family:inherit } pre.format { font-family:inherit } pre.smalldisplay { font-family:inherit; font-size:smaller } pre.smallformat { font-family:inherit; font-size:smaller } pre.smallexample { font-size:smaller } pre.smalllisp { font-size:smaller } span.sc { font-variant:small-caps } span.roman { font-family: serif; font-weight: normal; } --></style> </head> <body> <div class="node"> <p> <a name="AVR_002dModifiers"></a>Previous: <a rel="previous" accesskey="p" href="AVR_002dRegs.html#AVR_002dRegs">AVR-Regs</a>, Up: <a rel="up" accesskey="u" href="AVR-Syntax.html#AVR-Syntax">AVR Syntax</a> <hr><br> </div> <h5 class="subsubsection">9.4.2.3 Relocatable Expression Modifiers</h5> <p><a name="index-AVR-modifiers-654"></a><a name="index-syntax_002c-AVR-655"></a> The assembler supports several modifiers when using relocatable addresses in AVR instruction operands. The general syntax is the following: <pre class="smallexample"> modifier(relocatable-expression) </pre> <a name="index-symbol-modifiers-656"></a> <dl> <dt><code>lo8</code><dd> This modifier allows you to use bits 0 through 7 of an address expression as 8 bit relocatable expression. <br><dt><code>hi8</code><dd> This modifier allows you to use bits 7 through 15 of an address expression as 8 bit relocatable expression. This is useful with, for example, the AVR <span class="samp">ldi</span> instruction and <span class="samp">lo8</span> modifier. <p>For example <pre class="smallexample"> ldi r26, lo8(sym+10) ldi r27, hi8(sym+10) </pre> <br><dt><code>hh8</code><dd> This modifier allows you to use bits 16 through 23 of an address expression as 8 bit relocatable expression. Also, can be useful for loading 32 bit constants. <br><dt><code>hlo8</code><dd> Synonym of <span class="samp">hh8</span>. <br><dt><code>hhi8</code><dd> This modifier allows you to use bits 24 through 31 of an expression as 8 bit expression. This is useful with, for example, the AVR <span class="samp">ldi</span> instruction and <span class="samp">lo8</span>, <span class="samp">hi8</span>, <span class="samp">hlo8</span>, <span class="samp">hhi8</span>, modifier. <p>For example <pre class="smallexample"> ldi r26, lo8(285774925) ldi r27, hi8(285774925) ldi r28, hlo8(285774925) ldi r29, hhi8(285774925) ; r29,r28,r27,r26 = 285774925 </pre> <br><dt><code>pm_lo8</code><dd> This modifier allows you to use bits 0 through 7 of an address expression as 8 bit relocatable expression. This modifier useful for addressing data or code from Flash/Program memory. The using of <span class="samp">pm_lo8</span> similar to <span class="samp">lo8</span>. <br><dt><code>pm_hi8</code><dd> This modifier allows you to use bits 8 through 15 of an address expression as 8 bit relocatable expression. This modifier useful for addressing data or code from Flash/Program memory. <br><dt><code>pm_hh8</code><dd> This modifier allows you to use bits 15 through 23 of an address expression as 8 bit relocatable expression. This modifier useful for addressing data or code from Flash/Program memory. </dl> </body></html>