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97 lines
4.4 KiB
HTML
97 lines
4.4 KiB
HTML
4 years ago
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<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
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<html>
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<!-- This file documents the GNU Assembler "as".
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Copyright (C) 1991-2019 Free Software Foundation, Inc.
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Permission is granted to copy, distribute and/or modify this document
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under the terms of the GNU Free Documentation License, Version 1.3
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or any later version published by the Free Software Foundation;
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with no Invariant Sections, with no Front-Cover Texts, and with no
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Back-Cover Texts. A copy of the license is included in the
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section entitled "GNU Free Documentation License".
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-->
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<!-- Created by GNU Texinfo 6.4, http://www.gnu.org/software/texinfo/ -->
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<head>
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<title>H8/300-Regs (Using as)</title>
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<meta name="description" content="H8/300-Regs (Using as)">
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<meta name="keywords" content="H8/300-Regs (Using as)">
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<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
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<link href="index.html#Top" rel="start" title="Top">
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<link href="AS-Index.html#AS-Index" rel="index" title="AS Index">
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<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
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<link href="H8_002f300-Syntax.html#H8_002f300-Syntax" rel="up" title="H8/300 Syntax">
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<link href="H8_002f300_002dAddressing.html#H8_002f300_002dAddressing" rel="next" title="H8/300-Addressing">
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<link href="H8_002f300_002dChars.html#H8_002f300_002dChars" rel="prev" title="H8/300-Chars">
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</style>
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</head>
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<body lang="en">
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<a name="H8_002f300_002dRegs"></a>
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<div class="header">
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<p>
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Next: <a href="H8_002f300_002dAddressing.html#H8_002f300_002dAddressing" accesskey="n" rel="next">H8/300-Addressing</a>, Previous: <a href="H8_002f300_002dChars.html#H8_002f300_002dChars" accesskey="p" rel="prev">H8/300-Chars</a>, Up: <a href="H8_002f300-Syntax.html#H8_002f300-Syntax" accesskey="u" rel="up">H8/300 Syntax</a> [<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>
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</div>
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<hr>
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<a name="Register-Names-7"></a>
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<h4 class="subsubsection">9.13.2.2 Register Names</h4>
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<a name="index-H8_002f300-registers"></a>
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<a name="index-register-names_002c-H8_002f300"></a>
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<p>You can use predefined symbols of the form ‘<samp>r<var>n</var>h</samp>’ and
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‘<samp>r<var>n</var>l</samp>’ to refer to the H8/300 registers as sixteen 8-bit
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general-purpose registers. <var>n</var> is a digit from ‘<samp>0</samp>’ to
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‘<samp>7</samp>’); for instance, both ‘<samp>r0h</samp>’ and ‘<samp>r7l</samp>’ are valid
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register names.
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</p>
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<p>You can also use the eight predefined symbols ‘<samp>r<var>n</var></samp>’ to refer
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to the H8/300 registers as 16-bit registers (you must use this form for
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addressing).
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</p>
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<p>On the H8/300H, you can also use the eight predefined symbols
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‘<samp>er<var>n</var></samp>’ (‘<samp>er0</samp>’ … ‘<samp>er7</samp>’) to refer to the 32-bit
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general purpose registers.
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</p>
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<p>The two control registers are called <code>pc</code> (program counter; a
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16-bit register, except on the H8/300H where it is 24 bits) and
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<code>ccr</code> (condition code register; an 8-bit register). <code>r7</code> is
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used as the stack pointer, and can also be called <code>sp</code>.
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</p>
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</body>
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</html>
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