126 lines
6.8 KiB
HTML
126 lines
6.8 KiB
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<html lang="en">
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<head>
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<title>XGATE-Syntax - Using as</title>
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<meta name="description" content="Using as">
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<link title="Top" rel="start" href="index.html#Top">
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<link rel="up" href="XGATE_002dDependent.html#XGATE_002dDependent" title="XGATE-Dependent">
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<link rel="prev" href="XGATE_002dOpts.html#XGATE_002dOpts" title="XGATE-Opts">
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<link rel="next" href="XGATE_002dDirectives.html#XGATE_002dDirectives" title="XGATE-Directives">
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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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--></style>
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</head>
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<body>
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<div class="node">
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<a name="XGATE-Syntax"></a>
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<a name="XGATE_002dSyntax"></a>
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<p>
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Next: <a rel="next" accesskey="n" href="XGATE_002dDirectives.html#XGATE_002dDirectives">XGATE-Directives</a>,
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Previous: <a rel="previous" accesskey="p" href="XGATE_002dOpts.html#XGATE_002dOpts">XGATE-Opts</a>,
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Up: <a rel="up" accesskey="u" href="XGATE_002dDependent.html#XGATE_002dDependent">XGATE-Dependent</a>
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<hr>
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</div>
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<h4 class="subsection">9.53.2 Syntax</h4>
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<p><a name="index-XGATE-syntax-2566"></a><a name="index-syntax_002c-XGATE-2567"></a>
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In XGATE RISC syntax, the instruction name comes first and it may
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be followed by up to three operands. Operands are separated by commas
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(‘<samp><span class="samp">,</span></samp>’). <code>as</code> will complain if too many operands are specified
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for a given instruction. The same will happen if you specified too few
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operands.
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<pre class="smallexample"> nop
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ldl #23
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CMP R1, R2
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</pre>
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<p><a name="index-line-comment-character_002c-XGATE-2568"></a><a name="index-XGATE-line-comment-character-2569"></a>The presence of a ‘<samp><span class="samp">;</span></samp>’ character or a ‘<samp><span class="samp">!</span></samp>’ character anywhere
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on a line indicates the start of a comment that extends to the end of
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that line.
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<p>A ‘<samp><span class="samp">*</span></samp>’ or a ‘<samp><span class="samp">#</span></samp>’ character at the start of a line also
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introduces a line comment, but these characters do not work elsewhere
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on the line. If the first character of the line is a ‘<samp><span class="samp">#</span></samp>’ then as
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well as starting a comment, the line could also be logical line number
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directive (see <a href="Comments.html#Comments">Comments</a>) or a preprocessor control command
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(see <a href="Preprocessing.html#Preprocessing">Preprocessing</a>).
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<p><a name="index-line-separator_002c-XGATE-2570"></a><a name="index-statement-separator_002c-XGATE-2571"></a><a name="index-XGATE-line-separator-2572"></a>The XGATE assembler does not currently support a line separator
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character.
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<p><a name="index-XGATE-addressing-modes-2573"></a><a name="index-addressing-modes_002c-XGATE-2574"></a>The following addressing modes are understood for XGATE:
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<dl>
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<dt><dfn>Inherent</dfn><dd>‘<samp></samp>’
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<br><dt><dfn>Immediate 3 Bit Wide</dfn><dd>‘<samp><span class="samp">#</span><var>number</var></samp>’
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<br><dt><dfn>Immediate 4 Bit Wide</dfn><dd>‘<samp><span class="samp">#</span><var>number</var></samp>’
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<br><dt><dfn>Immediate 8 Bit Wide</dfn><dd>‘<samp><span class="samp">#</span><var>number</var></samp>’
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<br><dt><dfn>Monadic Addressing</dfn><dd>‘<samp><var>reg</var></samp>’
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<br><dt><dfn>Dyadic Addressing</dfn><dd>‘<samp><var>reg</var><span class="samp">, </span><var>reg</var></samp>’
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<br><dt><dfn>Triadic Addressing</dfn><dd>‘<samp><var>reg</var><span class="samp">, </span><var>reg</var><span class="samp">, </span><var>reg</var></samp>’
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<br><dt><dfn>Relative Addressing 9 Bit Wide</dfn><dd>‘<samp><span class="samp">*</span><var>symbol</var></samp>’
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<br><dt><dfn>Relative Addressing 10 Bit Wide</dfn><dd>‘<samp><span class="samp">*</span><var>symbol</var></samp>’
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<br><dt><dfn>Index Register plus Immediate Offset</dfn><dd>‘<samp><var>reg</var><span class="samp">, (</span><var>reg</var><span class="samp">, #</span><var>number</var><span class="samp">)</span></samp>’
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<br><dt><dfn>Index Register plus Register Offset</dfn><dd>‘<samp><var>reg</var><span class="samp">, </span><var>reg</var><span class="samp">, </span><var>reg</var></samp>’
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<br><dt><dfn>Index Register plus Register Offset with Post-increment</dfn><dd>‘<samp><var>reg</var><span class="samp">, </span><var>reg</var><span class="samp">, </span><var>reg</var><span class="samp">+</span></samp>’
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<br><dt><dfn>Index Register plus Register Offset with Pre-decrement</dfn><dd>‘<samp><var>reg</var><span class="samp">, </span><var>reg</var><span class="samp">, -</span><var>reg</var></samp>’
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<p>The register can be either ‘<samp><span class="samp">R0</span></samp>’, ‘<samp><span class="samp">R1</span></samp>’, ‘<samp><span class="samp">R2</span></samp>’, ‘<samp><span class="samp">R3</span></samp>’,
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‘<samp><span class="samp">R4</span></samp>’, ‘<samp><span class="samp">R5</span></samp>’, ‘<samp><span class="samp">R6</span></samp>’ or ‘<samp><span class="samp">R7</span></samp>’.
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</dl>
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<p>Convene macro opcodes to deal with 16-bit values have been added.
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<dl>
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<dt><dfn>Immediate 16 Bit Wide</dfn><dd>‘<samp><span class="samp">#</span><var>number</var></samp>’, or ‘<samp><span class="samp">*</span><var>symbol</var></samp>’
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<p>For example:
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<pre class="smallexample"> ldw R1, #1024
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ldw R3, timer
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ldw R1, (R1, #0)
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COM R1
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stw R2, (R1, #0)
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</pre>
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</dl>
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</body></html>
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