/** * \file fixedmath.h * \author Wei Yongming <ymwei@minigui.org> * \date 2002/01/12 *  *  This file includes fixed point and three-dimension math routines. * \verbatim    Copyright (C) 1998-2002 Wei Yongming.    Copyright (C) 2002-2003 Feynman Software.    This file is part of MiniGUI, a lightweight Graphics User Interface    support library for real-time embedded Linux.    This program is free software; you can redistribute it and/or modify    it under the terms of the GNU General Public License as published by    the Free Software Foundation; either version 2 of the License, or    (at your option) any later version.    This program is distributed in the hope that it will be useful,    but WITHOUT ANY WARRANTY; without even the implied warranty of    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the    GNU General Public License for more details.    You should have received a copy of the GNU General Public License    along with this program; if not, write to the Free Software    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA \endverbatim *//* * $Id: fixedmath.h,v 1.18 2004/02/25 02:34:49 weiym Exp $ * *             MiniGUI for Linux, uClinux, eCos, and uC/OS-II version 1.5.x *             Copyright (C) 1998-2002 Wei Yongming. *             Copyright (C) 2002-2004 Feynman Software. * *             Fix point math routins come from Allegro *             By Shawn Hargreaves and others. *             So thank for their great work and good license. * *             "Allegro is a gift-software"  * *         ______   ___    ___ *        /\  _  \ /\_ \  /\_ \ *        \ \ \L\ \\//\ \ \//\ \      __     __   _ __   ___ *         \ \  __ \ \ \ \  \ \ \   /'__`\ /'_ `\/\`'__\/ __`\ *          \ \ \/\ \ \_\ \_ \_\ \_/\  __//\ \L\ \ \ \//\ \L\ \ *           \ \_\ \_\/\____\/\____\ \____\ \____ \ \_\\ \____/ *            \/_/\/_/\/____/\/____/\/____/\/___L\ \/_/ \/___/ *                                           /\____/ *                                           \_/__/ * */#ifndef _MGUI_FIXED_MATH_H#define _MGUI_FIXED_MATH_H#include <errno.h>#include <math.h>/* Set up for C function definitions, even when using C++ */#ifdef __cplusplusextern "C" {#endif#ifdef _FIXED_MATH    /**     * \addtogroup fns Functions     * @{     */    /**     * \addtogroup global_fns Global/general functions     * @{     */    /**     * \defgroup fixed_math_fns Fixed point math functions     *      * You know that the float point mathematics routines are very     * expensive. If you do not want precision mathematics result,      * you can use fixed point. MiniGUI uses a double word (32-bit)     * integer to represent a fixed point ranged from -32767.0 to      * 32767.0, and defines some fixed point mathematics routines for      * your application. Some GDI functions need fixed point      * math routines, like \a Arc.     *     * Example 1:     *      * \include fixed_point.c     *     * Example 2:     *      * \include fixedpoint.c     * @{     *//** * \fn fixed fsqrt (fixed x) * \brief Returns the non-negative square root of a fixed point value. * * This function returns the non-negative square root of \a x. * It fails and sets errno to EDOM, if x is negative. * * \sa fhypot */fixed fsqrt (fixed x);/** * \fn fixed fhypot (fixed x, fixed y) * \brief Returns the Euclidean distance from the origin. *  * The function returns the \a sqrt(x*x+y*y). This is the length of  * the hypotenuse of a right-angle triangle with sides of length \a x and \a y,  * or the distance of the point \a (x,y) from the origin. * * \sa fsqrt */fixed fhypot (fixed x, fixed y);/** * \fn fixed fatan (fixed x) * \brief Calculates the arc tangent of a fixed point value. * * This function calculates the arc tangent of \a x; that is the value  * whose tangent is \a x. * * \return Returns the arc tangent in radians and the value is  *         mathematically defined to be between -PI/2 and PI/2 (inclusive). * * \sa fatan2 */fixed fatan (fixed x);/** * \fn fixed fatan2 (fixed y, fixed x) * \brief Calclulates the arc tangent of two fixed point variables. * *  This function calculates the arc tangent of the two variables \a x and \a y. *  It is similar to calculating the arc tangent of \a y / \a x, except that  *  the signs of both arguments are used to determine the quadrant of the result. * * \return Returns the result in radians, which is between -PI and PI (inclusive). * * \sa fatan */fixed fatan2 (fixed y, fixed x);extern fixed _cos_tbl[];extern fixed _tan_tbl[];extern fixed _acos_tbl[];/************************** inline fixed point math functions *****************//* ftofix and fixtof are used in generic C versions of fmul and fdiv *//** * \fn fixed ftofix (double x) * \brief Converts a float point value to a fixed point value. * * This function converts the specified float point value \a x to  * a fixed point value. * * \note The float point should be ranged from -32767.0 to 32767.0. * If it runs out of the range, this function sets \a errno to \a ERANGE. * * \sa fixtof */static inline fixed ftofix (double x){    if (x > 32767.0) {      errno = ERANGE;      return 0x7FFFFFFF;   }   if (x < -32767.0) {      errno = ERANGE;      return -0x7FFFFFFF;   }   return (long)(x * 65536.0 + (x < 0 ? -0.5 : 0.5)); }/** * \fn double fixtof (fixed x) * \brief Converts a fixed point value to a float point value. * * This function converts the specified fixed point value \a x to  * a float point value. * * \sa ftofix */static inline double fixtof (fixed x){    return (double)x / 65536.0; }/** * \fn fixed fadd (fixed x, fixed y) * \brief Returns the sum of two fixed point values. * * This function adds two fixed point values \a x and \a y, and * returns the sum. * * \param x x,y: Two addends. * \param y x,y: Two addends. * \return The sum. If the result runs out of range of fixed point, this function *         sets \a errno to \a ERANGE. * * \sa fsub */static inline fixed fadd (fixed x, fixed y){   fixed result = x + y;   if (result >= 0) {      if ((x < 0) && (y < 0)) {	 errno = ERANGE;	 return -0x7FFFFFFF;      }      else	 return result;   }   else {      if ((x > 0) && (y > 0)) {	 errno = ERANGE;	 return 0x7FFFFFFF;      }      else	 return result;   }}/** * \fn fixed fsub (fixed x, fixed y) * \brief Subtract a fixed point value from another. * * This function subtracts the fixed point values \a y from the fixed point value \a x, * and returns the difference. * * \param x The minuend. * \param y The subtrahend. * \return The difference. If the result runs out of range of fixed point, this function *         sets \a errno to \a ERANGE. * * \sa fadd */static inline fixed fsub (fixed x, fixed y){   fixed result = x - y;   if (result >= 0) {      if ((x < 0) && (y > 0)) {	 errno = ERANGE;	 return -0x7FFFFFFF;      }      else	 return result;   }   else {      if ((x > 0) && (y < 0)) {	 errno = ERANGE;	 return 0x7FFFFFFF;      }      else	 return result;   }}/** * \fn fixed fmul (fixed x, fixed y) * \brief Returns the product of two fixed point values. *  * This function returns the product of two fixed point values \a x and \a y. * * \param x The faciend. * \param y The multiplicato. * \return The prodcut. If the result runs out of range of fixed point, this function *         sets \a errno to \a ERANGE. *  * \sa fdiv */static inline fixed fmul (fixed x, fixed y){   return ftofix(fixtof(x) * fixtof(y));}/** * \fn fixed fdiv (fixed x, fixed y) * \brief Returns the quotient of two fixed point values. *  * This function returns the quotient of two fixed point values \a x and \a y. * * \param x The dividend. * \param y The divisor. * \return The quotient. If the result runs out of range of fixed point, this function *         sets \a errno to \a ERANGE. *  * \sa fmul */static inline fixed fdiv (fixed x, fixed y){   if (y == 0) {      errno = ERANGE;