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123 lines
5.3 KiB
HTML
123 lines
5.3 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>Z80 Opcodes (Using as)</title>
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<meta name="description" content="Z80 Opcodes (Using as)">
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<meta name="keywords" content="Z80 Opcodes (Using as)">
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<meta name="resource-type" content="document">
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<meta name="distribution" content="global">
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<meta name="Generator" content="makeinfo">
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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="Z80_002dDependent.html#Z80_002dDependent" rel="up" title="Z80-Dependent">
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<link href="Z8000_002dDependent.html#Z8000_002dDependent" rel="next" title="Z8000-Dependent">
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<link href="Z80-Directives.html#Z80-Directives" rel="prev" title="Z80 Directives">
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<style type="text/css">
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a.summary-letter {text-decoration: none}
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div.display {margin-left: 3.2em}
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div.example {margin-left: 3.2em}
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span.nolinebreak {white-space: nowrap}
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span.roman {font-family: initial; font-weight: normal}
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span.sansserif {font-family: sans-serif; font-weight: normal}
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ul.no-bullet {list-style: none}
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-->
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</style>
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</head>
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<body lang="en">
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<a name="Z80-Opcodes"></a>
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<div class="header">
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<p>
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Previous: <a href="Z80-Directives.html#Z80-Directives" accesskey="p" rel="prev">Z80 Directives</a>, Up: <a href="Z80_002dDependent.html#Z80_002dDependent" accesskey="u" rel="up">Z80-Dependent</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="Opcodes-22"></a>
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<h4 class="subsection">9.55.5 Opcodes</h4>
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<p>In line with common practice, Z80 mnemonics are used for both the Z80 and
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the R800.
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</p>
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<p>In many instructions it is possible to use one of the half index
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registers (‘<samp>ixl</samp>’,‘<samp>ixh</samp>’,‘<samp>iyl</samp>’,‘<samp>iyh</samp>’) in stead of an
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8-bit general purpose register. This yields instructions that are
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documented on the R800 and undocumented on the Z80.
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Similarly <code>in f,(c)</code> is documented on the R800 and undocumented on
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the Z80.
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</p>
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<p>The assembler also supports the following undocumented Z80-instructions,
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that have not been adopted in the R800 instruction set:
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</p><dl compact="compact">
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<dt><code>out (c),0</code></dt>
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<dd><p>Sends zero to the port pointed to by register c.
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</p>
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</dd>
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<dt><code>sli <var>m</var></code></dt>
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<dd><p>Equivalent to <code><var>m</var> = (<var>m</var><<1)+1</code>, the operand <var>m</var> can
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be any operand that is valid for ‘<samp>sla</samp>’. One can use ‘<samp>sll</samp>’ as a
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synonym for ‘<samp>sli</samp>’.
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</p>
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</dd>
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<dt><code><var>op</var> (ix+<var>d</var>), <var>r</var></code></dt>
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<dd><p>This is equivalent to
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</p>
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<div class="example">
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<pre class="example">ld <var>r</var>, (ix+<var>d</var>)
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<var>opc</var> <var>r</var>
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ld (ix+<var>d</var>), <var>r</var>
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</pre></div>
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<p>The operation ‘<samp><var>opc</var></samp>’ may be any of ‘<samp>res <var>b</var>,</samp>’,
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‘<samp>set <var>b</var>,</samp>’, ‘<samp>rl</samp>’, ‘<samp>rlc</samp>’, ‘<samp>rr</samp>’, ‘<samp>rrc</samp>’,
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‘<samp>sla</samp>’, ‘<samp>sli</samp>’, ‘<samp>sra</samp>’ and ‘<samp>srl</samp>’, and the register
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‘<samp><var>r</var></samp>’ may be any of ‘<samp>a</samp>’, ‘<samp>b</samp>’, ‘<samp>c</samp>’, ‘<samp>d</samp>’,
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‘<samp>e</samp>’, ‘<samp>h</samp>’ and ‘<samp>l</samp>’.
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</p>
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</dd>
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<dt><code><var>opc</var> (iy+<var>d</var>), <var>r</var></code></dt>
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<dd><p>As above, but with ‘<samp>iy</samp>’ instead of ‘<samp>ix</samp>’.
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</p></dd>
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</dl>
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<p>The web site at <a href="http://www.z80.info">http://www.z80.info</a> is a good starting place to
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find more information on programming the Z80.
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</p>
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</body>
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</html>
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