You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
116 lines
6.2 KiB
HTML
116 lines
6.2 KiB
HTML
<html lang="en">
|
|
<head>
|
|
<title>Options-i960 - Using as</title>
|
|
<meta http-equiv="Content-Type" content="text/html">
|
|
<meta name="description" content="Using as">
|
|
<meta name="generator" content="makeinfo 4.7">
|
|
<link title="Top" rel="start" href="index.html#Top">
|
|
<link rel="up" href="i960_002dDependent.html#i960_002dDependent" title="i960-Dependent">
|
|
<link rel="next" href="Floating-Point_002di960.html#Floating-Point_002di960" title="Floating Point-i960">
|
|
<link href="http://www.gnu.org/software/texinfo/" rel="generator-home" title="Texinfo Homepage">
|
|
<!--
|
|
This file documents the GNU Assembler "as".
|
|
|
|
Copyright (C) 1991, 92, 93, 94, 95, 96, 97, 98, 99, 2000, 2001, 2002,
|
|
2006, 2007 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 1.1
|
|
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''.
|
|
|
|
man end-->
|
|
<meta http-equiv="Content-Style-Type" content="text/css">
|
|
<style type="text/css"><!--
|
|
pre.display { font-family:inherit }
|
|
pre.format { font-family:inherit }
|
|
pre.smalldisplay { font-family:inherit; font-size:smaller }
|
|
pre.smallformat { font-family:inherit; font-size:smaller }
|
|
pre.smallexample { font-size:smaller }
|
|
pre.smalllisp { font-size:smaller }
|
|
span.sc { font-variant:small-caps }
|
|
span.roman { font-family: serif; font-weight: normal; }
|
|
--></style>
|
|
</head>
|
|
<body>
|
|
<div class="node">
|
|
<p>
|
|
<a name="Options_002di960"></a>Next: <a rel="next" accesskey="n" href="Floating-Point_002di960.html#Floating-Point_002di960">Floating Point-i960</a>,
|
|
Up: <a rel="up" accesskey="u" href="i960_002dDependent.html#i960_002dDependent">i960-Dependent</a>
|
|
<hr><br>
|
|
</div>
|
|
|
|
<h4 class="subsection">9.15.1 i960 Command-line Options</h4>
|
|
|
|
<p><a name="index-i960-options-975"></a><a name="index-options_002c-i960-976"></a>
|
|
|
|
<a name="index-i960-architecture-options-977"></a>
|
|
<a name="index-architecture-options_002c-i960-978"></a>
|
|
<a name="index-_0040code_007b_002dA_007d-options_002c-i960-979"></a>
|
|
<dl><dt><code>-ACA | -ACA_A | -ACB | -ACC | -AKA | -AKB | -AKC | -AMC</code><dd>Select the 80960 architecture. Instructions or features not supported
|
|
by the selected architecture cause fatal errors.
|
|
|
|
<p><span class="samp">-ACA</span> is equivalent to <span class="samp">-ACA_A</span>; <span class="samp">-AKC</span> is equivalent to
|
|
<span class="samp">-AMC</span>. Synonyms are provided for compatibility with other tools.
|
|
|
|
<p>If you do not specify any of these options, <code>as</code> generates code
|
|
for any instruction or feature that is supported by <em>some</em> version of the
|
|
960 (even if this means mixing architectures!). In principle,
|
|
<code>as</code> attempts to deduce the minimal sufficient processor type if
|
|
none is specified; depending on the object code format, the processor type may
|
|
be recorded in the object file. If it is critical that the <code>as</code>
|
|
output match a specific architecture, specify that architecture explicitly.
|
|
|
|
<p><a name="index-_0040code_007b_002db_007d-option_002c-i960-980"></a><a name="index-branch-recording_002c-i960-981"></a><a name="index-i960-branch-recording-982"></a><br><dt><code>-b</code><dd>Add code to collect information about conditional branches taken, for
|
|
later optimization using branch prediction bits. (The conditional branch
|
|
instructions have branch prediction bits in the CA, CB, and CC
|
|
architectures.) If <var>BR</var> represents a conditional branch instruction,
|
|
the following represents the code generated by the assembler when
|
|
<span class="samp">-b</span> is specified:
|
|
|
|
<pre class="smallexample"> call <var>increment routine</var>
|
|
.word 0 # pre-counter
|
|
Label: <var>BR</var>
|
|
call <var>increment routine</var>
|
|
.word 0 # post-counter
|
|
</pre>
|
|
<p>The counter following a branch records the number of times that branch
|
|
was <em>not</em> taken; the difference between the two counters is the
|
|
number of times the branch <em>was</em> taken.
|
|
|
|
<p><a name="index-_0040code_007bgbr960_007d_002c-i960-postprocessor-983"></a><a name="index-branch-statistics-table_002c-i960-984"></a>A table of every such <code>Label</code> is also generated, so that the
|
|
external postprocessor <code>gbr960</code> (supplied by Intel) can locate all
|
|
the counters. This table is always labeled <span class="samp">__BRANCH_TABLE__</span>;
|
|
this is a local symbol to permit collecting statistics for many separate
|
|
object files. The table is word aligned, and begins with a two-word
|
|
header. The first word, initialized to 0, is used in maintaining linked
|
|
lists of branch tables. The second word is a count of the number of
|
|
entries in the table, which follow immediately: each is a word, pointing
|
|
to one of the labels illustrated above.
|
|
|
|
<!-- TEXI2ROFF-KILL -->
|
|
<!-- END TEXI2ROFF-KILL -->
|
|
<p>The first word of the header is used to locate multiple branch tables,
|
|
since each object file may contain one. Normally the links are
|
|
maintained with a call to an initialization routine, placed at the
|
|
beginning of each function in the file. The <span class="sc">gnu</span> C compiler
|
|
generates these calls automatically when you give it a <span class="samp">-b</span> option.
|
|
For further details, see the documentation of <span class="samp">gbr960</span>.
|
|
|
|
<p><a name="index-_0040code_007b_002dno_002drelax_007d-option_002c-i960-985"></a><br><dt><code>-no-relax</code><dd>Normally, Compare-and-Branch instructions with targets that require
|
|
displacements greater than 13 bits (or that have external targets) are
|
|
replaced with the corresponding compare (or <span class="samp">chkbit</span>) and branch
|
|
instructions. You can use the <span class="samp">-no-relax</span> option to specify that
|
|
<code>as</code> should generate errors instead, if the target displacement
|
|
is larger than 13 bits.
|
|
|
|
<p>This option does not affect the Compare-and-Jump instructions; the code
|
|
emitted for them is <em>always</em> adjusted when necessary (depending on
|
|
displacement size), regardless of whether you use <span class="samp">-no-relax</span>.
|
|
</dl>
|
|
|
|
</body></html>
|
|
|