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8 | <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> |
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9 | 00002 <span class="comment">//*****************************************************************************</span> |
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10 | 00003 <span class="comment">//</span> |
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11 | 00004 <span class="comment">// File Name : 'fixedpt.c'</span> |
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12 | 00005 <span class="comment">// Title : Fixed-point math function library</span> |
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13 | 00006 <span class="comment">// Author : Pascal Stang - Copyright (C) 2003</span> |
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14 | 00007 <span class="comment">// Created : 2003.01.26</span> |
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15 | 00008 <span class="comment">// Revised : 2003.02.02</span> |
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16 | 00009 <span class="comment">// Version : 0.1</span> |
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17 | 00010 <span class="comment">// Target MCU : Atmel AVR Series</span> |
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18 | 00011 <span class="comment">// Editor Tabs : 4</span> |
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19 | 00012 <span class="comment">//</span> |
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20 | 00013 <span class="comment">// NOTE: This code is currently below version 1.0, and therefore is considered</span> |
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21 | 00014 <span class="comment">// to be lacking in some functionality or documentation, or may not be fully</span> |
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22 | 00015 <span class="comment">// tested. Nonetheless, you can expect most functions to work.</span> |
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23 | 00016 <span class="comment">//</span> |
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24 | 00017 <span class="comment">// This code is distributed under the GNU Public License</span> |
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25 | 00018 <span class="comment">// which can be found at http://www.gnu.org/licenses/gpl.txt</span> |
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26 | 00019 <span class="comment">//</span> |
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27 | 00020 <span class="comment">//*****************************************************************************</span> |
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28 | 00021 |
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29 | 00022 |
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30 | 00023 <span class="preprocessor">#include "<a class="code" href="fixedpt_8h.html">fixedpt.h</a>"</span> |
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31 | 00024 |
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32 | 00025 <span class="comment">// Program ROM constants</span> |
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33 | 00026 |
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34 | 00027 <span class="comment">// Global variables</span> |
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35 | 00028 u08 FixedPtBits; |
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36 | 00029 |
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37 | 00030 <span class="comment">// Functions</span> |
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38 | 00031 |
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39 | 00032 <span class="comment">// fixedptInit() initializes fixed-point math function library</span> |
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40 | <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) |
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41 | 00034 { |
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42 | 00035 <span class="comment">// set the number of bits to use behind the point</span> |
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43 | 00036 FixedPtBits = fixedPtBits; |
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44 | 00037 } |
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45 | 00038 |
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46 | <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) |
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47 | 00040 { |
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48 | 00041 <span class="comment">// convert integer to fixed-point number</span> |
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49 | 00042 <span class="keywordflow">return</span> (int_number<<FixedPtBits); |
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50 | 00043 } |
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51 | 00044 |
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52 | <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) |
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53 | 00046 { |
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54 | 00047 <span class="comment">// convert fixed-point number to integer</span> |
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55 | 00048 <span class="comment">// do rounding</span> |
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56 | 00049 <span class="keywordflow">if</span>( fp_number & 1<<(FixedPtBits-1) ) |
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57 | 00050 { |
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58 | 00051 <span class="comment">// bit behind the point was a '1'</span> |
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59 | 00052 <span class="comment">// round up to next higher integer</span> |
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60 | 00053 <span class="keywordflow">return</span> (fp_number>>FixedPtBits)+1; |
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61 | 00054 } |
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62 | 00055 <span class="keywordflow">else</span> |
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63 | 00056 { |
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64 | 00057 <span class="comment">// bit behind the point was a '0'</span> |
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65 | 00058 <span class="comment">// round down (truncate) to next lower integer</span> |
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66 | 00059 <span class="keywordflow">return</span> (fp_number>>FixedPtBits); |
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67 | 00060 } |
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68 | 00061 } |
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69 | 00062 |
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70 | <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) |
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71 | 00064 { |
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72 | 00065 <span class="comment">// add a and b (a+b) with fixed-point math</span> |
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73 | 00066 <span class="keywordflow">return</span> a+b; |
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74 | 00067 } |
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75 | 00068 |
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76 | <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) |
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77 | 00070 { |
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78 | 00071 <span class="comment">// subtract a and b (a-b) with fixed-point math</span> |
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79 | 00072 <span class="keywordflow">return</span> a-b; |
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80 | 00073 } |
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81 | 00074 |
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82 | <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) |
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83 | 00076 { |
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84 | 00077 <span class="comment">// multiply a and b (a*b) with fixed-point math</span> |
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85 | 00078 <span class="keywordflow">return</span> (a*b)>>FixedPtBits; |
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86 | 00079 } |
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87 | 00080 |
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88 | <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) |
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89 | 00082 { |
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90 | 00083 <span class="comment">// divide numer by denom (numer/denom) with fixed-point math</span> |
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91 | 00084 <span class="keywordflow">return</span> (numer<<FixedPtBits)/denom; |
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92 | 00085 } |
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93 | </pre></div><hr size="1"><address style="align: right;"><small>Generated on Sun Oct 29 03:41:06 2006 for Procyon AVRlib by |
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95 | <img src="doxygen.png" alt="doxygen" align="middle" border="0"></a> 1.4.2 </small></address> |
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