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/*

Copyright 2007, Niklas Nold

This program (files math.c and math.h) is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation;
either version 3 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 Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.

Please note: All the other files for the project "Mikrokopter" by H. Buss are under the license (license_buss.txt) published by www.mikrokopter.de
*/


#include "main.h"


const uint8_t pgm_atan[270] PROGMEM = {0,1,2,3,5,6,7,8,9,10,11,12,13,15,16,17,18,19,20,21,22,23,24,25,26,27,27,28,29,30,31,32,33,33,34,35,36,37,37,38,39,39,40,41,41,42,43,43,44,44,45,46,46,47,47,48,48,49,49,50,50,51,51,52,52,52,53,53,54,54,54,55,55,56,56,56,57,57,57,58,58,58,59,59,59,60,60,60,60,61,61,61,61,62,62,62,62,63,63,63,63,64,64,64,64,65,65,65,65,65,66,66,66,66,66,67,67,67,67,67,67,68,68,68,68,68,68,69,69,69,69,69,69,69,70,70,70,70,70,70,70,70,71,71,71,71,71,71,71,71,72,72,72,72,72,72,72,72,72,73,73,73,73,73,73,73,73,73,73,74,74,74,74,74,74,74,74,74,74,74,74,75,75,75,75,75,75,75,75,75,75,75,75,75,76,76,76,76,76,76,76,76,76,76,76,76,76,76,76,77,77,77,77,77,77,77,77,77,77,77,77,77,77,77,77,77,78,78,78,78,78,78,78,78,78,78,78,78,78,78,78,78,78,78,78,78,79,79,79,79,79,79,79,79,79,79,79,79,79,79,79,79,79,79,79,79,79,79,79,79};

//############################################################################
// Arkustangens2 im Gradmaß
signed int atan2_i(signed int x,  signed int y)
//############################################################################
{
        int i,angle;
        int8_t m;
       
        if (!x && !y) return 0;         //atan2 = 0 für x und y = 0
       
        if (y < 0) m=-1;
        else m=1;
       
        if (x==0) return (90*m);                // atan2 = 90° für x = 0
       
        i = abs(((long)y*50) / x);              // Berechne i für die Lookup table (Schrittweite atan(x) ist 0.02 -> *50)

        if (i<270) angle = pgm_read_byte(&pgm_atan[i]); // Lookup für 1° bis 79°
        else if (i>5750) angle = 90;                                            // Grenzwert ist 90°
        else if (i>=1910) angle = 89;                                           // 89° bis 80° über Wertebereiche
        else if (i>=1150) angle = 88;
        else if (i>=820) angle = 87;
        else if (i>=640) angle = 86;
        else if (i>=520) angle = 85;
        else if (i>=440) angle = 84;
        else if (i>=380) angle = 83;
        else if (i>=335) angle = 82;
        else if (i>=299) angle = 81;
        else angle = 80; // (i>=270)
       
        if (x > 0) return (angle*m);    // Quadrant I und IV
        else if ((x < 0) && (m > 0)) return (-angle + 180);     // Quadrant II
        else return (angle - 180); // x < 0 && y < 0    Quadrant III
}


const float pgm_sinus_f[91] PROGMEM = {0.0,0.01745241,0.03489950,0.05233595,0.06975647,0.08715574,0.10452846,0.12186934,0.13917310,0.15643446,0.17364817,0.19080899,0.20791168,0.22495105,0.24192189,0.25881904,0.27563735,0.29237170,0.30901699,0.32556815,0.34202013,0.35836794,0.37460658,0.39073112,0.40673663,0.42261825,0.43837113,0.45399049,0.46947155,0.48480961,0.49999999,0.51503806,0.52991925,0.54463902,0.55919289,0.57357642,0.58778524,0.60181501,0.61566146,0.62932038,0.64278759,0.65605901,0.66913059,0.68199834,0.69465835,0.70710676,0.71933978,0.73135368,0.74314481,0.75470956,0.76604443,0.77714594,0.78801074,0.79863549,0.80901698,0.81915203,0.82903756,0.83867055,0.84804808,0.85716728,0.86602539,0.87461969,0.88294758,0.89100651,0.89879403,0.90630777,0.91354544,0.92050484,0.92718384,0.93358041,0.93969261,0.94551856,0.95105650,0.95630474,0.96126169,0.96592582,0.97029572,0.97437006,0.97814759,0.98162718,0.98480775,0.98768833,0.99026806,0.99254615,0.99452189,0.99619469,0.99756405,0.99862953,0.99939083,0.99984769,1.0};

inline float pgm_read_float(const float *addr)
{      
        union
        {
                uint16_t i[2];  // 2 16-bit-Worte
                float f;
        } u;
       
        u.i[0]=pgm_read_word((PGM_P)addr);
        u.i[1]=pgm_read_word((PGM_P)addr+2);
       
        return u.f;
}

//############################################################################
// Kosinusfunktion im Gradmaß
float cos_f(signed int winkel)
//############################################################################
{
 return (sin_f(90-winkel));
}

//############################################################################
// Sinusfunktion im Gradmaß
float sin_f(signed int winkel)
//############################################################################
{
 short int m,n;
 float sinus;
 
 //winkel = winkel % 360;
 
 if (winkel < 0)
 {
        m = -1;
        winkel = abs(winkel);
 }
 else m = +1;
 
 // Quadranten auswerten
 if (winkel <= 90) n=1;
 else if ((winkel > 90 ) && (winkel <= 180)) {winkel = 180 - winkel; n = 1;}
 else if ((winkel > 180 ) && (winkel <= 270)) {winkel = winkel - 180; n = -1;}
 else {winkel = 360 - winkel; n = -1;}  //if ((winkel > 270) && (winkel <= 360))

 sinus = pgm_read_float(&pgm_sinus_f[winkel]);

return (sinus*m*n);
}


const uint8_t pgm_asin[201] PROGMEM = {0,0,1,1,1,1,2,2,2,3,3,3,3,4,4,4,5,5,5,5,6,6,6,7,7,7,7,8,8,8,9,9,9,9,10,10,10,11,11,11,12,12,12,12,13,13,13,14,14,14,14,15,15,15,16,16,16,17,17,17,17,18,18,18,19,19,19,20,20,20,20,21,21,21,22,22,22,23,23,23,24,24,24,25,25,25,25,26,26,26,27,27,27,28,28,28,29,29,29,30,30,30,31,31,31,32,32,32,33,33,33,34,34,34,35,35,35,36,36,37,37,37,38,38,38,39,39,39,40,40,41,41,41,42,42,42,43,43,44,44,44,45,45,46,46,46,47,47,48,48,49,49,49,50,50,51,51,52,52,53,53,54,54,55,55,56,56,57,57,58,58,59,59,60,60,61,62,62,63,64,64,65,66,66,67,68,68,69,70,71,72,73,74,75,76,77,79,80,82,84,90};

//############################################################################
// Akurssinusfunktion im Gradmaß
int8_t asin_i(signed int i)
//############################################################################
{
        signed char m;
       
        if (i < 0) {m=-1;i=abs(i);}
        else m=1;
       
        i = i % 200;
       
        return (pgm_read_byte(&pgm_asin[i]) * m);
}