<html lang="en"> <head> <title>H8/300 Opcodes - Using as</title> <meta http-equiv="Content-Type" content="text/html"> <meta name="description" content="Using as"> <meta name="generator" content="makeinfo 4.13"> <link title="Top" rel="start" href="index.html#Top"> <link rel="up" href="H8_002f300_002dDependent.html#H8_002f300_002dDependent" title="H8/300-Dependent"> <link rel="prev" href="H8_002f300-Directives.html#H8_002f300-Directives" title="H8/300 Directives"> <link href="http://www.gnu.org/software/texinfo/" rel="generator-home" title="Texinfo Homepage"> <!-- This file documents the GNU Assembler "as". Copyright (C) 1991-2015 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 1.3 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''. --> <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; } span.sansserif { font-family:sans-serif; font-weight:normal; } --></style> </head> <body> <div class="node"> <a name="H8%2f300-Opcodes"></a> <a name="H8_002f300-Opcodes"></a> <p> Previous: <a rel="previous" accesskey="p" href="H8_002f300-Directives.html#H8_002f300-Directives">H8/300 Directives</a>, Up: <a rel="up" accesskey="u" href="H8_002f300_002dDependent.html#H8_002f300_002dDependent">H8/300-Dependent</a> <hr> </div> <h4 class="subsection">9.12.5 Opcodes</h4> <p><a name="index-H8_002f300-opcode-summary-960"></a><a name="index-opcode-summary_002c-H8_002f300-961"></a><a name="index-mnemonics_002c-H8_002f300-962"></a><a name="index-instruction-summary_002c-H8_002f300-963"></a>For detailed information on the H8/300 machine instruction set, see <cite>H8/300 Series Programming Manual</cite>. For information specific to the H8/300H, see <cite>H8/300H Series Programming Manual</cite> (Renesas). <p><code>as</code> implements all the standard H8/300 opcodes. No additional pseudo-instructions are needed on this family. <p><a name="index-size-suffixes_002c-H8_002f300-964"></a><a name="index-H8_002f300-size-suffixes-965"></a>Four H8/300 instructions (<code>add</code>, <code>cmp</code>, <code>mov</code>, <code>sub</code>) are defined with variants using the suffixes ‘<samp><span class="samp">.b</span></samp>’, ‘<samp><span class="samp">.w</span></samp>’, and ‘<samp><span class="samp">.l</span></samp>’ to specify the size of a memory operand. <code>as</code> supports these suffixes, but does not require them; since one of the operands is always a register, <code>as</code> can deduce the correct size. <p>For example, since <code>r0</code> refers to a 16-bit register, <pre class="example"> mov r0,@foo <br>is equivalent to<br> mov.w r0,@foo </pre> <p>If you use the size suffixes, <code>as</code> issues a warning when the suffix and the register size do not match. <!-- Copyright (C) 1991-2015 Free Software Foundation, Inc. --> <!-- This is part of the GAS manual. --> <!-- For copying conditions, see the file as.texinfo. --> </body></html>