1<html><head><meta http-equiv="Content-Type" content="text/html; charset=ANSI_X3.4-1968"><title>Accessing Port Space</title><meta name="generator" content="DocBook XSL Stylesheets V1.78.1"><link rel="home" href="index.html" title="Bus-Independent Device Accesses"><link rel="up" href="port_space_accesses.html" title="Chapter&#160;4.&#160;Port Space Accesses"><link rel="prev" href="port_space_accesses.html" title="Chapter&#160;4.&#160;Port Space Accesses"><link rel="next" href="pubfunctions.html" title="Chapter&#160;5.&#160;Public Functions Provided"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Accessing Port Space</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="port_space_accesses.html">Prev</a>&#160;</td><th width="60%" align="center">Chapter&#160;4.&#160;Port Space Accesses</th><td width="20%" align="right">&#160;<a accesskey="n" href="pubfunctions.html">Next</a></td></tr></table><hr></div><div class="sect1"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="accessing_port_space"></a>Accessing Port Space</h2></div></div></div><p>
2	Accesses to this space are provided through a set of functions
3	which allow 8-bit, 16-bit and 32-bit accesses; also
4	known as byte, word and long.  These functions are
5	<code class="function">inb</code>, <code class="function">inw</code>,
6	<code class="function">inl</code>, <code class="function">outb</code>,
7	<code class="function">outw</code> and <code class="function">outl</code>.
8      </p><p>
9	Some variants are provided for these functions.  Some devices
10	require that accesses to their ports are slowed down.  This
11	functionality is provided by appending a <code class="function">_p</code>
12	to the end of the function.  There are also equivalents to memcpy.
13	The <code class="function">ins</code> and <code class="function">outs</code>
14	functions copy bytes, words or longs to the given port.
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