154 lines
6.7 KiB
HTML
154 lines
6.7 KiB
HTML
|
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
|
||
|
|
<html>
|
||
|
|
<!-- This file documents the GNU Assembler "as".
|
||
|
|
|
||
|
|
Copyright (C) 1991-2016 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".
|
||
|
|
-->
|
||
|
|
<!-- Created by GNU Texinfo 5.2, http://www.gnu.org/software/texinfo/ -->
|
||
|
|
<head>
|
||
|
|
<title>Using as: s390 Operands</title>
|
||
|
|
|
||
|
|
<meta name="description" content="Using as: s390 Operands">
|
||
|
|
<meta name="keywords" content="Using as: s390 Operands">
|
||
|
|
<meta name="resource-type" content="document">
|
||
|
|
<meta name="distribution" content="global">
|
||
|
|
<meta name="Generator" content="makeinfo">
|
||
|
|
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
|
||
|
|
<link href="index.html#Top" rel="start" title="Top">
|
||
|
|
<link href="AS-Index.html#AS-Index" rel="index" title="AS Index">
|
||
|
|
<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
|
||
|
|
<link href="s390-Syntax.html#s390-Syntax" rel="up" title="s390 Syntax">
|
||
|
|
<link href="s390-Formats.html#s390-Formats" rel="next" title="s390 Formats">
|
||
|
|
<link href="s390-Mnemonics.html#s390-Mnemonics" rel="prev" title="s390 Mnemonics">
|
||
|
|
<style type="text/css">
|
||
|
|
<!--
|
||
|
|
a.summary-letter {text-decoration: none}
|
||
|
|
blockquote.smallquotation {font-size: smaller}
|
||
|
|
div.display {margin-left: 3.2em}
|
||
|
|
div.example {margin-left: 3.2em}
|
||
|
|
div.indentedblock {margin-left: 3.2em}
|
||
|
|
div.lisp {margin-left: 3.2em}
|
||
|
|
div.smalldisplay {margin-left: 3.2em}
|
||
|
|
div.smallexample {margin-left: 3.2em}
|
||
|
|
div.smallindentedblock {margin-left: 3.2em; font-size: smaller}
|
||
|
|
div.smalllisp {margin-left: 3.2em}
|
||
|
|
kbd {font-style:oblique}
|
||
|
|
pre.display {font-family: inherit}
|
||
|
|
pre.format {font-family: inherit}
|
||
|
|
pre.menu-comment {font-family: serif}
|
||
|
|
pre.menu-preformatted {font-family: serif}
|
||
|
|
pre.smalldisplay {font-family: inherit; font-size: smaller}
|
||
|
|
pre.smallexample {font-size: smaller}
|
||
|
|
pre.smallformat {font-family: inherit; font-size: smaller}
|
||
|
|
pre.smalllisp {font-size: smaller}
|
||
|
|
span.nocodebreak {white-space:nowrap}
|
||
|
|
span.nolinebreak {white-space:nowrap}
|
||
|
|
span.roman {font-family:serif; font-weight:normal}
|
||
|
|
span.sansserif {font-family:sans-serif; font-weight:normal}
|
||
|
|
ul.no-bullet {list-style: none}
|
||
|
|
-->
|
||
|
|
</style>
|
||
|
|
|
||
|
|
|
||
|
|
</head>
|
||
|
|
|
||
|
|
<body lang="en" bgcolor="#FFFFFF" text="#000000" link="#0000FF" vlink="#800080" alink="#FF0000">
|
||
|
|
<a name="s390-Operands"></a>
|
||
|
|
<div class="header">
|
||
|
|
<p>
|
||
|
|
Next: <a href="s390-Formats.html#s390-Formats" accesskey="n" rel="next">s390 Formats</a>, Previous: <a href="s390-Mnemonics.html#s390-Mnemonics" accesskey="p" rel="prev">s390 Mnemonics</a>, Up: <a href="s390-Syntax.html#s390-Syntax" accesskey="u" rel="up">s390 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>
|
||
|
|
</div>
|
||
|
|
<hr>
|
||
|
|
<a name="Instruction-Operands"></a>
|
||
|
|
<h4 class="subsubsection">9.38.3.3 Instruction Operands</h4>
|
||
|
|
<a name="index-instruction-operands_002c-s390"></a>
|
||
|
|
<a name="index-s390-instruction-operands"></a>
|
||
|
|
|
||
|
|
<p>Instruction operands can be grouped into three classes, operands located
|
||
|
|
in registers, immediate operands, and operands in storage.
|
||
|
|
</p>
|
||
|
|
<p>A register operand can be located in general, floating-point, access,
|
||
|
|
or control register. The register is identified by a four-bit field.
|
||
|
|
The field containing the register operand is called the R field.
|
||
|
|
</p>
|
||
|
|
<p>Immediate operands are contained within the instruction and can have
|
||
|
|
8, 16 or 32 bits. The field containing the immediate operand is called
|
||
|
|
the I field. Dependent on the instruction the I field is either signed
|
||
|
|
or unsigned.
|
||
|
|
</p>
|
||
|
|
<p>A storage operand consists of an address and a length. The address of a
|
||
|
|
storage operands can be specified in any of these ways:
|
||
|
|
</p>
|
||
|
|
<ul>
|
||
|
|
<li> The content of a single general R
|
||
|
|
</li><li> The sum of the content of a general register called the base
|
||
|
|
register B plus the content of a displacement field D
|
||
|
|
</li><li> The sum of the contents of two general registers called the
|
||
|
|
index register X and the base register B plus the content of a
|
||
|
|
displacement field
|
||
|
|
</li><li> The sum of the current instruction address and a 32-bit signed
|
||
|
|
immediate field multiplied by two.
|
||
|
|
</li></ul>
|
||
|
|
|
||
|
|
<p>The length of a storage operand can be:
|
||
|
|
</p>
|
||
|
|
<ul>
|
||
|
|
<li> Implied by the instruction
|
||
|
|
</li><li> Specified by a bitmask
|
||
|
|
</li><li> Specified by a four-bit or eight-bit length field L
|
||
|
|
</li><li> Specified by the content of a general register
|
||
|
|
</li></ul>
|
||
|
|
|
||
|
|
<p>The notation for storage operand addresses formed from multiple fields is
|
||
|
|
as follows:
|
||
|
|
</p>
|
||
|
|
<dl compact="compact">
|
||
|
|
<dt><code>Dn(Bn)</code></dt>
|
||
|
|
<dd><p>the address for operand number n is formed from the content of general
|
||
|
|
register Bn called the base register and the displacement field Dn.
|
||
|
|
</p></dd>
|
||
|
|
<dt><code>Dn(Xn,Bn)</code></dt>
|
||
|
|
<dd><p>the address for operand number n is formed from the content of general
|
||
|
|
register Xn called the index register, general register Bn called the
|
||
|
|
base register and the displacement field Dn.
|
||
|
|
</p></dd>
|
||
|
|
<dt><code>Dn(Ln,Bn)</code></dt>
|
||
|
|
<dd><p>the address for operand number n is formed from the content of general
|
||
|
|
regiser Bn called the base register and the displacement field Dn.
|
||
|
|
The length of the operand n is specified by the field Ln.
|
||
|
|
</p></dd>
|
||
|
|
</dl>
|
||
|
|
|
||
|
|
<p>The base registers Bn and the index registers Xn of a storage operand can
|
||
|
|
be skipped. If Bn and Xn are skipped, a zero will be stored to the operand
|
||
|
|
field. The notation changes as follows:
|
||
|
|
</p>
|
||
|
|
<div class="display">
|
||
|
|
<table>
|
||
|
|
<thead><tr><th width="30%"><pre class="display">full notation</pre></th><th width="30%"><pre class="display">short notation</pre></th></tr></thead>
|
||
|
|
<tr><td width="30%"><pre class="display">Dn(0,Bn)</pre></td><td width="30%"><pre class="display">Dn(Bn)</pre></td></tr>
|
||
|
|
<tr><td width="30%"><pre class="display">Dn(0,0)</pre></td><td width="30%"><pre class="display">Dn</pre></td></tr>
|
||
|
|
<tr><td width="30%"><pre class="display">Dn(0)</pre></td><td width="30%"><pre class="display">Dn</pre></td></tr>
|
||
|
|
<tr><td width="30%"><pre class="display">Dn(Ln,0)</pre></td><td width="30%"><pre class="display">Dn(Ln)</pre></td></tr>
|
||
|
|
</table>
|
||
|
|
</div>
|
||
|
|
|
||
|
|
|
||
|
|
<hr>
|
||
|
|
<div class="header">
|
||
|
|
<p>
|
||
|
|
Next: <a href="s390-Formats.html#s390-Formats" accesskey="n" rel="next">s390 Formats</a>, Previous: <a href="s390-Mnemonics.html#s390-Mnemonics" accesskey="p" rel="prev">s390 Mnemonics</a>, Up: <a href="s390-Syntax.html#s390-Syntax" accesskey="u" rel="up">s390 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>
|
||
|
|
</div>
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
</body>
|
||
|
|
</html>
|