72 lines
3.7 KiB
HTML
72 lines
3.7 KiB
HTML
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<html lang="en">
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<title>H8/300-Regs - Using as</title>
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<link title="Top" rel="start" href="index.html#Top">
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<link rel="up" href="H8_002f300-Syntax.html#H8_002f300-Syntax" title="H8/300 Syntax">
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<link rel="prev" href="H8_002f300_002dChars.html#H8_002f300_002dChars" title="H8/300-Chars">
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<link rel="next" href="H8_002f300_002dAddressing.html#H8_002f300_002dAddressing" title="H8/300-Addressing">
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<link href="http://www.gnu.org/software/texinfo/" rel="generator-home" title="Texinfo Homepage">
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<!--
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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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</head>
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<body>
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<div class="node">
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<a name="H8%2f300-Regs"></a>
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<a name="H8_002f300_002dRegs"></a>
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<p>
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Next: <a rel="next" accesskey="n" href="H8_002f300_002dAddressing.html#H8_002f300_002dAddressing">H8/300-Addressing</a>,
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Previous: <a rel="previous" accesskey="p" href="H8_002f300_002dChars.html#H8_002f300_002dChars">H8/300-Chars</a>,
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Up: <a rel="up" accesskey="u" href="H8_002f300-Syntax.html#H8_002f300-Syntax">H8/300 Syntax</a>
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<hr>
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</div>
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<h5 class="subsubsection">9.14.2.2 Register Names</h5>
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<p><a name="index-H8_002f300-registers-1049"></a><a name="index-register-names_002c-H8_002f300-1050"></a>You can use predefined symbols of the form ‘<samp><span class="samp">r</span><var>n</var><span class="samp">h</span></samp>’ and
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‘<samp><span class="samp">r</span><var>n</var><span class="samp">l</span></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><span class="samp">0</span></samp>’ to
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‘<samp><span class="samp">7</span></samp>’); for instance, both ‘<samp><span class="samp">r0h</span></samp>’ and ‘<samp><span class="samp">r7l</span></samp>’ are valid
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register names.
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<p>You can also use the eight predefined symbols ‘<samp><span class="samp">r</span><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>On the H8/300H, you can also use the eight predefined symbols
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‘<samp><span class="samp">er</span><var>n</var></samp>’ (‘<samp><span class="samp">er0</span></samp>’ <small class="dots">...</small> ‘<samp><span class="samp">er7</span></samp>’) to refer to the 32-bit
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general purpose registers.
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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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</body></html>
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