256 lines
11 KiB
HTML
256 lines
11 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: Blackfin Syntax</title>
|
||
|
|
|
||
|
|
<meta name="description" content="Using as: Blackfin Syntax">
|
||
|
|
<meta name="keywords" content="Using as: Blackfin 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="Blackfin_002dDependent.html#Blackfin_002dDependent" rel="up" title="Blackfin-Dependent">
|
||
|
|
<link href="Blackfin-Directives.html#Blackfin-Directives" rel="next" title="Blackfin Directives">
|
||
|
|
<link href="Blackfin-Options.html#Blackfin-Options" rel="prev" title="Blackfin 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="Blackfin-Syntax"></a>
|
||
|
|
<div class="header">
|
||
|
|
<p>
|
||
|
|
Next: <a href="Blackfin-Directives.html#Blackfin-Directives" accesskey="n" rel="next">Blackfin Directives</a>, Previous: <a href="Blackfin-Options.html#Blackfin-Options" accesskey="p" rel="prev">Blackfin Options</a>, Up: <a href="Blackfin_002dDependent.html#Blackfin_002dDependent" accesskey="u" rel="up">Blackfin-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-7"></a>
|
||
|
|
<h4 class="subsection">9.6.2 Syntax</h4>
|
||
|
|
<a name="index-Blackfin-syntax"></a>
|
||
|
|
<a name="index-syntax_002c-Blackfin"></a>
|
||
|
|
|
||
|
|
<dl compact="compact">
|
||
|
|
<dt><code>Special Characters</code></dt>
|
||
|
|
<dd><p>Assembler input is free format and may appear anywhere on the line.
|
||
|
|
One instruction may extend across multiple lines or more than one
|
||
|
|
instruction may appear on the same line. White space (space, tab,
|
||
|
|
comments or newline) may appear anywhere between tokens. A token must
|
||
|
|
not have embedded spaces. Tokens include numbers, register names,
|
||
|
|
keywords, user identifiers, and also some multicharacter special
|
||
|
|
symbols like "+=", "/*" or "||".
|
||
|
|
</p>
|
||
|
|
<p>Comments are introduced by the ‘<samp>#</samp>’ character and extend to the
|
||
|
|
end of the current line. If the ‘<samp>#</samp>’ appears as the first
|
||
|
|
character of a line, the whole line is treated as a comment, but in
|
||
|
|
this case the line can also be a logical line number directive
|
||
|
|
(see <a href="Comments.html#Comments">Comments</a>) or a preprocessor control command
|
||
|
|
(see <a href="Preprocessing.html#Preprocessing">Preprocessing</a>).
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code>Instruction Delimiting</code></dt>
|
||
|
|
<dd><p>A semicolon must terminate every instruction. Sometimes a complete
|
||
|
|
instruction will consist of more than one operation. There are two
|
||
|
|
cases where this occurs. The first is when two general operations
|
||
|
|
are combined. Normally a comma separates the different parts, as in
|
||
|
|
</p>
|
||
|
|
<div class="smallexample">
|
||
|
|
<pre class="smallexample">a0= r3.h * r2.l, a1 = r3.l * r2.h ;
|
||
|
|
</pre></div>
|
||
|
|
|
||
|
|
<p>The second case occurs when a general instruction is combined with one
|
||
|
|
or two memory references for joint issue. The latter portions are
|
||
|
|
set off by a "||" token.
|
||
|
|
</p>
|
||
|
|
<div class="smallexample">
|
||
|
|
<pre class="smallexample">a0 = r3.h * r2.l || r1 = [p3++] || r4 = [i2++];
|
||
|
|
</pre></div>
|
||
|
|
|
||
|
|
<p>Multiple instructions can occur on the same line. Each must be
|
||
|
|
terminated by a semicolon character.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code>Register Names</code></dt>
|
||
|
|
<dd>
|
||
|
|
<p>The assembler treats register names and instruction keywords in a case
|
||
|
|
insensitive manner. User identifiers are case sensitive. Thus, R3.l,
|
||
|
|
R3.L, r3.l and r3.L are all equivalent input to the assembler.
|
||
|
|
</p>
|
||
|
|
<p>Register names are reserved and may not be used as program identifiers.
|
||
|
|
</p>
|
||
|
|
<p>Some operations (such as "Move Register") require a register pair.
|
||
|
|
Register pairs are always data registers and are denoted using a colon,
|
||
|
|
eg., R3:2. The larger number must be written firsts. Note that the
|
||
|
|
hardware only supports odd-even pairs, eg., R7:6, R5:4, R3:2, and R1:0.
|
||
|
|
</p>
|
||
|
|
<p>Some instructions (such as –SP (Push Multiple)) require a group of
|
||
|
|
adjacent registers. Adjacent registers are denoted in the syntax by
|
||
|
|
the range enclosed in parentheses and separated by a colon, eg., (R7:3).
|
||
|
|
Again, the larger number appears first.
|
||
|
|
</p>
|
||
|
|
<p>Portions of a particular register may be individually specified. This
|
||
|
|
is written with a dot (".") following the register name and then a
|
||
|
|
letter denoting the desired portion. For 32-bit registers, ".H"
|
||
|
|
denotes the most significant ("High") portion. ".L" denotes the
|
||
|
|
least-significant portion. The subdivisions of the 40-bit registers
|
||
|
|
are described later.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code>Accumulators</code></dt>
|
||
|
|
<dd><p>The set of 40-bit registers A1 and A0 that normally contain data that
|
||
|
|
is being manipulated. Each accumulator can be accessed in four ways.
|
||
|
|
</p>
|
||
|
|
<dl compact="compact">
|
||
|
|
<dt><code>one 40-bit register</code></dt>
|
||
|
|
<dd><p>The register will be referred to as A1 or A0.
|
||
|
|
</p></dd>
|
||
|
|
<dt><code>one 32-bit register</code></dt>
|
||
|
|
<dd><p>The registers are designated as A1.W or A0.W.
|
||
|
|
</p></dd>
|
||
|
|
<dt><code>two 16-bit registers</code></dt>
|
||
|
|
<dd><p>The registers are designated as A1.H, A1.L, A0.H or A0.L.
|
||
|
|
</p></dd>
|
||
|
|
<dt><code>one 8-bit register</code></dt>
|
||
|
|
<dd><p>The registers are designated as A1.X or A0.X for the bits that
|
||
|
|
extend beyond bit 31.
|
||
|
|
</p></dd>
|
||
|
|
</dl>
|
||
|
|
|
||
|
|
</dd>
|
||
|
|
<dt><code>Data Registers</code></dt>
|
||
|
|
<dd><p>The set of 32-bit registers (R0, R1, R2, R3, R4, R5, R6 and R7) that
|
||
|
|
normally contain data for manipulation. These are abbreviated as
|
||
|
|
D-register or Dreg. Data registers can be accessed as 32-bit registers
|
||
|
|
or as two independent 16-bit registers. The least significant 16 bits
|
||
|
|
of each register is called the "low" half and is designated with ".L"
|
||
|
|
following the register name. The most significant 16 bits are called
|
||
|
|
the "high" half and is designated with ".H" following the name.
|
||
|
|
</p>
|
||
|
|
<div class="smallexample">
|
||
|
|
<pre class="smallexample"> R7.L, r2.h, r4.L, R0.H
|
||
|
|
</pre></div>
|
||
|
|
|
||
|
|
</dd>
|
||
|
|
<dt><code>Pointer Registers</code></dt>
|
||
|
|
<dd><p>The set of 32-bit registers (P0, P1, P2, P3, P4, P5, SP and FP) that
|
||
|
|
normally contain byte addresses of data structures. These are
|
||
|
|
abbreviated as P-register or Preg.
|
||
|
|
</p>
|
||
|
|
<div class="smallexample">
|
||
|
|
<pre class="smallexample">p2, p5, fp, sp
|
||
|
|
</pre></div>
|
||
|
|
|
||
|
|
</dd>
|
||
|
|
<dt><code>Stack Pointer SP</code></dt>
|
||
|
|
<dd><p>The stack pointer contains the 32-bit address of the last occupied
|
||
|
|
byte location in the stack. The stack grows by decrementing the
|
||
|
|
stack pointer.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code>Frame Pointer FP</code></dt>
|
||
|
|
<dd><p>The frame pointer contains the 32-bit address of the previous frame
|
||
|
|
pointer in the stack. It is located at the top of a frame.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code>Loop Top</code></dt>
|
||
|
|
<dd><p>LT0 and LT1. These registers contain the 32-bit address of the top of
|
||
|
|
a zero overhead loop.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code>Loop Count</code></dt>
|
||
|
|
<dd><p>LC0 and LC1. These registers contain the 32-bit counter of the zero
|
||
|
|
overhead loop executions.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code>Loop Bottom</code></dt>
|
||
|
|
<dd><p>LB0 and LB1. These registers contain the 32-bit address of the bottom
|
||
|
|
of a zero overhead loop.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code>Index Registers</code></dt>
|
||
|
|
<dd><p>The set of 32-bit registers (I0, I1, I2, I3) that normally contain byte
|
||
|
|
addresses of data structures. Abbreviated I-register or Ireg.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code>Modify Registers</code></dt>
|
||
|
|
<dd><p>The set of 32-bit registers (M0, M1, M2, M3) that normally contain
|
||
|
|
offset values that are added and subtracted to one of the index
|
||
|
|
registers. Abbreviated as Mreg.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code>Length Registers</code></dt>
|
||
|
|
<dd><p>The set of 32-bit registers (L0, L1, L2, L3) that normally contain the
|
||
|
|
length in bytes of the circular buffer. Abbreviated as Lreg. Clear
|
||
|
|
the Lreg to disable circular addressing for the corresponding Ireg.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code>Base Registers</code></dt>
|
||
|
|
<dd><p>The set of 32-bit registers (B0, B1, B2, B3) that normally contain the
|
||
|
|
base address in bytes of the circular buffer. Abbreviated as Breg.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code>Floating Point</code></dt>
|
||
|
|
<dd><p>The Blackfin family has no hardware floating point but the .float
|
||
|
|
directive generates ieee floating point numbers for use with software
|
||
|
|
floating point libraries.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code>Blackfin Opcodes</code></dt>
|
||
|
|
<dd><p>For detailed information on the Blackfin machine instruction set, see
|
||
|
|
the Blackfin(r) Processor Instruction Set Reference.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
</dl>
|
||
|
|
|
||
|
|
<hr>
|
||
|
|
<div class="header">
|
||
|
|
<p>
|
||
|
|
Next: <a href="Blackfin-Directives.html#Blackfin-Directives" accesskey="n" rel="next">Blackfin Directives</a>, Previous: <a href="Blackfin-Options.html#Blackfin-Options" accesskey="p" rel="prev">Blackfin Options</a>, Up: <a href="Blackfin_002dDependent.html#Blackfin_002dDependent" accesskey="u" rel="up">Blackfin-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>
|