| <!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) 1991-2013 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: Compare-and-branch-i960</title> |
| |
| <meta name="description" content="Using as: Compare-and-branch-i960"> |
| <meta name="keywords" content="Using as: Compare-and-branch-i960"> |
| <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="Opcodes-for-i960.html#Opcodes-for-i960" rel="up" title="Opcodes for i960"> |
| <link href="Syntax-of-i960.html#Syntax-of-i960" rel="next" title="Syntax of i960"> |
| <link href="callj_002di960.html#callj_002di960" rel="prev" title="callj-i960"> |
| <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="Compare_002dand_002dbranch_002di960"></a> |
| <div class="header"> |
| <p> |
| Previous: <a href="callj_002di960.html#callj_002di960" accesskey="p" rel="prev">callj-i960</a>, Up: <a href="Opcodes-for-i960.html#Opcodes-for-i960" accesskey="u" rel="up">Opcodes for i960</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="Compare_002dand_002dBranch"></a> |
| <h4 class="subsubsection">9.17.4.2 Compare-and-Branch</h4> |
| |
| <a name="index-i960-compare_002fbranch-instructions"></a> |
| <a name="index-compare_002fbranch-instructions_002c-i960"></a> |
| <p>The 960 architectures provide combined Compare-and-Branch instructions |
| that permit you to store the branch target in the lower 13 bits of the |
| instruction word itself. However, if you specify a branch target far |
| enough away that its address won’t fit in 13 bits, the assembler can |
| either issue an error, or convert your Compare-and-Branch instruction |
| into separate instructions to do the compare and the branch. |
| </p> |
| <a name="index-compare-and-jump-expansions_002c-i960"></a> |
| <a name="index-i960-compare-and-jump-expansions"></a> |
| <p>Whether <code>as</code> gives an error or expands the instruction depends |
| on two choices you can make: whether you use the ‘<samp>-no-relax</samp>’ option, |
| and whether you use a “Compare and Branch” instruction or a “Compare |
| and Jump” instruction. The “Jump” instructions are <em>always</em> |
| expanded if necessary; the “Branch” instructions are expanded when |
| necessary <em>unless</em> you specify <code>-no-relax</code>—in which case |
| <code>as</code> gives an error instead. |
| </p> |
| <p>These are the Compare-and-Branch instructions, their “Jump” variants, |
| and the instruction pairs they may expand into: |
| </p> |
| |
| |
| |
| |
| </body> |
| </html> |
