123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133 |
- <!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) 1991-2017 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: ESA/390 Syntax</title>
- <meta name="description" content="Using as: ESA/390 Syntax">
- <meta name="keywords" content="Using as: ESA/390 Syntax">
- <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="ESA_002f390_002dDependent.html#ESA_002f390_002dDependent" rel="up" title="ESA/390-Dependent">
- <link href="ESA_002f390-Floating-Point.html#ESA_002f390-Floating-Point" rel="next" title="ESA/390 Floating Point">
- <link href="ESA_002f390-Options.html#ESA_002f390-Options" rel="prev" title="ESA/390 Options">
- <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="ESA_002f390-Syntax"></a>
- <div class="header">
- <p>
- Next: <a href="ESA_002f390-Floating-Point.html#ESA_002f390-Floating-Point" accesskey="n" rel="next">ESA/390 Floating Point</a>, Previous: <a href="ESA_002f390-Options.html#ESA_002f390-Options" accesskey="p" rel="prev">ESA/390 Options</a>, Up: <a href="ESA_002f390_002dDependent.html#ESA_002f390_002dDependent" accesskey="u" rel="up">ESA/390-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>
- </div>
- <hr>
- <a name="Syntax-13"></a>
- <h4 class="subsection">9.14.3 Syntax</h4>
- <p>The opcode/operand syntax follows the ESA/390 Principles of Operation
- manual; assembler directives and general syntax are loosely based on the
- prevailing AT&T/SVR4/ELF/Solaris style notation. HLASM-style directives
- are <em>not</em> supported for the most part, with the exception of those
- described herein.
- </p>
- <p>A leading dot in front of directives is optional, and the case of
- directives is ignored; thus for example, .using and USING have the same
- effect.
- </p>
- <p>A colon may immediately follow a label definition. This is
- simply for compatibility with how most assembly language programmers
- write code.
- </p>
- <p>‘<samp>#</samp>’ is the line comment character.
- </p>
- <p>‘<samp>;</samp>’ can be used instead of a newline to separate statements.
- </p>
- <p>Since ‘<samp>$</samp>’ has no special meaning, you may use it in symbol names.
- </p>
- <p>Registers can be given the symbolic names r0..r15, fp0, fp2, fp4, fp6.
- By using thesse symbolic names, <code>as</code> can detect simple
- syntax errors. The name rarg or r.arg is a synonym for r11, rtca or r.tca
- for r12, sp, r.sp, dsa r.dsa for r13, lr or r.lr for r14, rbase or r.base
- for r3 and rpgt or r.pgt for r4.
- </p>
- <p>‘<samp>*</samp>’ is the current location counter. Unlike ‘<samp>.</samp>’ it is always
- relative to the last USING directive. Note that this means that
- expressions cannot use multiplication, as any occurrence of ‘<samp>*</samp>’
- will be interpreted as a location counter.
- </p>
- <p>All labels are relative to the last USING. Thus, branches to a label
- always imply the use of base+displacement.
- </p>
- <p>Many of the usual forms of address constants / address literals
- are supported. Thus,
- </p><div class="example">
- <pre class="example"> .using *,r3
- L r15,=A(some_routine)
- LM r6,r7,=V(some_longlong_extern)
- A r1,=F'12'
- AH r0,=H'42'
- ME r6,=E'3.1416'
- MD r6,=D'3.14159265358979'
- O r6,=XL4'cacad0d0'
- .ltorg
- </pre></div>
- <p>should all behave as expected: that is, an entry in the literal
- pool will be created (or reused if it already exists), and the
- instruction operands will be the displacement into the literal pool
- using the current base register (as last declared with the <code>.using</code>
- directive).
- </p>
- <hr>
- <div class="header">
- <p>
- Next: <a href="ESA_002f390-Floating-Point.html#ESA_002f390-Floating-Point" accesskey="n" rel="next">ESA/390 Floating Point</a>, Previous: <a href="ESA_002f390-Options.html#ESA_002f390-Options" accesskey="p" rel="prev">ESA/390 Options</a>, Up: <a href="ESA_002f390_002dDependent.html#ESA_002f390_002dDependent" accesskey="u" rel="up">ESA/390-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>
- </div>
- </body>
- </html>
|