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86 lines
2.1 KiB
C
Executable File
86 lines
2.1 KiB
C
Executable File
/*! \file fixedpt.c \brief Fixed-point math function library. */
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//*****************************************************************************
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//
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// File Name : 'fixedpt.c'
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// Title : Fixed-point math function library
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// Author : Pascal Stang - Copyright (C) 2003
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// Created : 2003.01.26
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// Revised : 2003.02.02
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// Version : 0.1
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// Target MCU : Atmel AVR Series
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// Editor Tabs : 4
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//
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// NOTE: This code is currently below version 1.0, and therefore is considered
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// to be lacking in some functionality or documentation, or may not be fully
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// tested. Nonetheless, you can expect most functions to work.
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//
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// This code is distributed under the GNU Public License
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// which can be found at http://www.gnu.org/licenses/gpl.txt
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//
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//*****************************************************************************
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#include "fixedpt.h"
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// Program ROM constants
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// Global variables
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u08 FixedPtBits;
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// Functions
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// fixedptInit() initializes fixed-point math function library
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void fixedptInit(u08 fixedPtBits)
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{
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// set the number of bits to use behind the point
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FixedPtBits = fixedPtBits;
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}
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s32 fixedptConvertFromInt(s32 int_number)
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{
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// convert integer to fixed-point number
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return (int_number<<FixedPtBits);
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}
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s32 fixedptConvertToInt(s32 fp_number)
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{
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// convert fixed-point number to integer
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// do rounding
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if( fp_number & 1<<(FixedPtBits-1) )
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{
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// bit behind the point was a '1'
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// round up to next higher integer
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return (fp_number>>FixedPtBits)+1;
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}
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else
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{
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// bit behind the point was a '0'
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// round down (truncate) to next lower integer
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return (fp_number>>FixedPtBits);
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}
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}
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s32 fixedptAdd(s32 a, s32 b)
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{
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// add a and b (a+b) with fixed-point math
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return a+b;
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}
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s32 fixedptSubtract(s32 a, s32 b)
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{
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// subtract a and b (a-b) with fixed-point math
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return a-b;
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}
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s32 fixedptMultiply(s32 a, s32 b)
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{
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// multiply a and b (a*b) with fixed-point math
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return (a*b)>>FixedPtBits;
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}
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s32 fixedptDivide(s32 numer, s32 denom)
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{
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// divide numer by denom (numer/denom) with fixed-point math
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return (numer<<FixedPtBits)/denom;
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}
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