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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html><head><meta http-equiv="Content-Type" content="text/html;charset=iso-8859-1"><title>Procyon AVRlib: fixedpt.c Source File</title><link href="dox.css" rel="stylesheet" type="text/css"></head><body><!-- Generated by Doxygen 1.4.2 --><div class="qindex"><a class="qindex" href="main.html">Main Page</a> | <a class="qindex" href="modules.html">Modules</a> | <a class="qindex" href="annotated.html">Data Structures</a> | <a class="qindex" href="dirs.html">Directories</a> | <a class="qindex" href="files.html">File List</a> | <a class="qindex" href="functions.html">Data Fields</a> | <a class="qindex" href="globals.html">Globals</a> | <a class="qindex" href="pages.html">Related Pages</a></div><h1>fixedpt.c</h1><a href="fixedpt_8c.html">Go to the documentation of this file.</a><div class="fragment"><pre class="fragment">00001 <span class="comment">/*! \file fixedpt.c \brief Fixed-point math function library. */</span>00002 <span class="comment">//*****************************************************************************</span>00003 <span class="comment">//</span>00004 <span class="comment">// File Name : 'fixedpt.c'</span>00005 <span class="comment">// Title : Fixed-point math function library</span>00006 <span class="comment">// Author : Pascal Stang - Copyright (C) 2003</span>00007 <span class="comment">// Created : 2003.01.26</span>00008 <span class="comment">// Revised : 2003.02.02</span>00009 <span class="comment">// Version : 0.1</span>00010 <span class="comment">// Target MCU : Atmel AVR Series</span>00011 <span class="comment">// Editor Tabs : 4</span>00012 <span class="comment">//</span>00013 <span class="comment">// NOTE: This code is currently below version 1.0, and therefore is considered</span>00014 <span class="comment">// to be lacking in some functionality or documentation, or may not be fully</span>00015 <span class="comment">// tested. Nonetheless, you can expect most functions to work.</span>00016 <span class="comment">//</span>00017 <span class="comment">// This code is distributed under the GNU Public License</span>00018 <span class="comment">// which can be found at http://www.gnu.org/licenses/gpl.txt</span>00019 <span class="comment">//</span>00020 <span class="comment">//*****************************************************************************</span>00021 00022 00023 <span class="preprocessor">#include "<a class="code" href="fixedpt_8h.html">fixedpt.h</a>"</span>00024 00025 <span class="comment">// Program ROM constants</span>00026 00027 <span class="comment">// Global variables</span>00028 u08 FixedPtBits;00029 00030 <span class="comment">// Functions</span>00031 00032 <span class="comment">// fixedptInit() initializes fixed-point math function library</span><a name="l00033"></a><a class="code" href="fixedpt_8h.html#a0">00033</a> <span class="keywordtype">void</span> <a class="code" href="fixedpt_8c.html#a1">fixedptInit</a>(u08 fixedPtBits)00034 {00035 <span class="comment">// set the number of bits to use behind the point</span>00036 FixedPtBits = fixedPtBits;00037 }00038 <a name="l00039"></a><a class="code" href="fixedpt_8h.html#a1">00039</a> s32 <a class="code" href="fixedpt_8c.html#a2">fixedptConvertFromInt</a>(s32 int_number)00040 {00041 <span class="comment">// convert integer to fixed-point number</span>00042 <span class="keywordflow">return</span> (int_number<<FixedPtBits);00043 }00044 <a name="l00045"></a><a class="code" href="fixedpt_8h.html#a2">00045</a> s32 <a class="code" href="fixedpt_8c.html#a3">fixedptConvertToInt</a>(s32 fp_number)00046 {00047 <span class="comment">// convert fixed-point number to integer</span>00048 <span class="comment">// do rounding</span>00049 <span class="keywordflow">if</span>( fp_number & 1<<(FixedPtBits-1) )00050 {00051 <span class="comment">// bit behind the point was a '1'</span>00052 <span class="comment">// round up to next higher integer</span>00053 <span class="keywordflow">return</span> (fp_number>>FixedPtBits)+1;00054 }00055 <span class="keywordflow">else</span>00056 {00057 <span class="comment">// bit behind the point was a '0'</span>00058 <span class="comment">// round down (truncate) to next lower integer</span>00059 <span class="keywordflow">return</span> (fp_number>>FixedPtBits);00060 }00061 }00062 <a name="l00063"></a><a class="code" href="fixedpt_8h.html#a3">00063</a> s32 <a class="code" href="fixedpt_8c.html#a4">fixedptAdd</a>(s32 a, s32 b)00064 {00065 <span class="comment">// add a and b (a+b) with fixed-point math</span>00066 <span class="keywordflow">return</span> a+b;00067 }00068 <a name="l00069"></a><a class="code" href="fixedpt_8h.html#a4">00069</a> s32 <a class="code" href="fixedpt_8c.html#a5">fixedptSubtract</a>(s32 a, s32 b)00070 {00071 <span class="comment">// subtract a and b (a-b) with fixed-point math</span>00072 <span class="keywordflow">return</span> a-b;00073 }00074 <a name="l00075"></a><a class="code" href="fixedpt_8h.html#a5">00075</a> s32 <a class="code" href="fixedpt_8c.html#a6">fixedptMultiply</a>(s32 a, s32 b)00076 {00077 <span class="comment">// multiply a and b (a*b) with fixed-point math</span>00078 <span class="keywordflow">return</span> (a*b)>>FixedPtBits;00079 }00080 <a name="l00081"></a><a class="code" href="fixedpt_8h.html#a6">00081</a> s32 <a class="code" href="fixedpt_8c.html#a7">fixedptDivide</a>(s32 numer, s32 denom)00082 {00083 <span class="comment">// divide numer by denom (numer/denom) with fixed-point math</span>00084 <span class="keywordflow">return</span> (numer<<FixedPtBits)/denom;00085 }</pre></div><hr size="1"><address style="align: right;"><small>Generated on Mon Oct 24 16:03:54 2005 for Procyon AVRlib by <a href="http://www.doxygen.org/index.html"><img src="doxygen.png" alt="doxygen" align="middle" border="0"></a> 1.4.2 </small></address></body></html>⌨️ 快捷键说明
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