<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
|
<html>
|
<!-- Copyright (C) 1988-2016 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 the
|
Invariant Sections being "Funding Free Software", the Front-Cover
|
Texts being (a) (see below), and with the Back-Cover Texts being (b)
|
(see below). A copy of the license is included in the section entitled
|
"GNU Free Documentation License".
|
|
(a) The FSF's Front-Cover Text is:
|
|
A GNU Manual
|
|
(b) The FSF's Back-Cover Text is:
|
|
You have freedom to copy and modify this GNU Manual, like GNU
|
software. Copies published by the Free Software Foundation raise
|
funds for GNU development. -->
|
<!-- Created by GNU Texinfo 5.2, http://www.gnu.org/software/texinfo/ -->
|
<head>
|
<title>Using the GNU Compiler Collection (GCC): MSP430 Function Attributes</title>
|
|
<meta name="description" content="Using the GNU Compiler Collection (GCC): MSP430 Function Attributes">
|
<meta name="keywords" content="Using the GNU Compiler Collection (GCC): MSP430 Function Attributes">
|
<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="Option-Index.html#Option-Index" rel="index" title="Option Index">
|
<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
|
<link href="Function-Attributes.html#Function-Attributes" rel="up" title="Function Attributes">
|
<link href="NDS32-Function-Attributes.html#NDS32-Function-Attributes" rel="next" title="NDS32 Function Attributes">
|
<link href="MIPS-Function-Attributes.html#MIPS-Function-Attributes" rel="prev" title="MIPS Function Attributes">
|
<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="MSP430-Function-Attributes"></a>
|
<div class="header">
|
<p>
|
Next: <a href="NDS32-Function-Attributes.html#NDS32-Function-Attributes" accesskey="n" rel="next">NDS32 Function Attributes</a>, Previous: <a href="MIPS-Function-Attributes.html#MIPS-Function-Attributes" accesskey="p" rel="prev">MIPS Function Attributes</a>, Up: <a href="Function-Attributes.html#Function-Attributes" accesskey="u" rel="up">Function Attributes</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Option-Index.html#Option-Index" title="Index" rel="index">Index</a>]</p>
|
</div>
|
<hr>
|
<a name="MSP430-Function-Attributes-1"></a>
|
<h4 class="subsection">6.31.19 MSP430 Function Attributes</h4>
|
|
<p>These function attributes are supported by the MSP430 back end:
|
</p>
|
<dl compact="compact">
|
<dt><code>critical</code></dt>
|
<dd><a name="index-critical-function-attribute_002c-MSP430"></a>
|
<p>Critical functions disable interrupts upon entry and restore the
|
previous interrupt state upon exit. Critical functions cannot also
|
have the <code>naked</code> or <code>reentrant</code> attributes. They can have
|
the <code>interrupt</code> attribute.
|
</p>
|
</dd>
|
<dt><code>interrupt</code></dt>
|
<dd><a name="index-interrupt-function-attribute_002c-MSP430"></a>
|
<p>Use this attribute to indicate
|
that the specified function is an interrupt handler. The compiler generates
|
function entry and exit sequences suitable for use in an interrupt handler
|
when this attribute is present.
|
</p>
|
<p>You can provide an argument to the interrupt
|
attribute which specifies a name or number. If the argument is a
|
number it indicates the slot in the interrupt vector table (0 - 31) to
|
which this handler should be assigned. If the argument is a name it
|
is treated as a symbolic name for the vector slot. These names should
|
match up with appropriate entries in the linker script. By default
|
the names <code>watchdog</code> for vector 26, <code>nmi</code> for vector 30 and
|
<code>reset</code> for vector 31 are recognized.
|
</p>
|
</dd>
|
<dt><code>naked</code></dt>
|
<dd><a name="index-naked-function-attribute_002c-MSP430"></a>
|
<p>This attribute allows the compiler to construct the
|
requisite function declaration, while allowing the body of the
|
function to be assembly code. The specified function will not have
|
prologue/epilogue sequences generated by the compiler. Only basic
|
<code>asm</code> statements can safely be included in naked functions
|
(see <a href="Basic-Asm.html#Basic-Asm">Basic Asm</a>). While using extended <code>asm</code> or a mixture of
|
basic <code>asm</code> and C code may appear to work, they cannot be
|
depended upon to work reliably and are not supported.
|
</p>
|
</dd>
|
<dt><code>reentrant</code></dt>
|
<dd><a name="index-reentrant-function-attribute_002c-MSP430"></a>
|
<p>Reentrant functions disable interrupts upon entry and enable them
|
upon exit. Reentrant functions cannot also have the <code>naked</code>
|
or <code>critical</code> attributes. They can have the <code>interrupt</code>
|
attribute.
|
</p>
|
</dd>
|
<dt><code>wakeup</code></dt>
|
<dd><a name="index-wakeup-function-attribute_002c-MSP430"></a>
|
<p>This attribute only applies to interrupt functions. It is silently
|
ignored if applied to a non-interrupt function. A wakeup interrupt
|
function will rouse the processor from any low-power state that it
|
might be in when the function exits.
|
</p>
|
</dd>
|
<dt><code>lower</code></dt>
|
<dt><code>upper</code></dt>
|
<dt><code>either</code></dt>
|
<dd><a name="index-lower-function-attribute_002c-MSP430"></a>
|
<a name="index-upper-function-attribute_002c-MSP430"></a>
|
<a name="index-either-function-attribute_002c-MSP430"></a>
|
<p>On the MSP430 target these attributes can be used to specify whether
|
the function or variable should be placed into low memory, high
|
memory, or the placement should be left to the linker to decide. The
|
attributes are only significant if compiling for the MSP430X
|
architecture.
|
</p>
|
<p>The attributes work in conjunction with a linker script that has been
|
augmented to specify where to place sections with a <code>.lower</code> and
|
a <code>.upper</code> prefix. So, for example, as well as placing the
|
<code>.data</code> section, the script also specifies the placement of a
|
<code>.lower.data</code> and a <code>.upper.data</code> section. The intention
|
is that <code>lower</code> sections are placed into a small but easier to
|
access memory region and the upper sections are placed into a larger, but
|
slower to access, region.
|
</p>
|
<p>The <code>either</code> attribute is special. It tells the linker to place
|
the object into the corresponding <code>lower</code> section if there is
|
room for it. If there is insufficient room then the object is placed
|
into the corresponding <code>upper</code> section instead. Note that the
|
placement algorithm is not very sophisticated. It does not attempt to
|
find an optimal packing of the <code>lower</code> sections. It just makes
|
one pass over the objects and does the best that it can. Using the
|
<samp>-ffunction-sections</samp> and <samp>-fdata-sections</samp> command-line
|
options can help the packing, however, since they produce smaller,
|
easier to pack regions.
|
</p></dd>
|
</dl>
|
|
<hr>
|
<div class="header">
|
<p>
|
Next: <a href="NDS32-Function-Attributes.html#NDS32-Function-Attributes" accesskey="n" rel="next">NDS32 Function Attributes</a>, Previous: <a href="MIPS-Function-Attributes.html#MIPS-Function-Attributes" accesskey="p" rel="prev">MIPS Function Attributes</a>, Up: <a href="Function-Attributes.html#Function-Attributes" accesskey="u" rel="up">Function Attributes</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Option-Index.html#Option-Index" title="Index" rel="index">Index</a>]</p>
|
</div>
|
|
|
|
</body>
|
</html>
|
