/*
 * Metro Siberia 4 - A sequel to Dark Storm's Metro Siberia 3 for CASIO calculators.
 * Copyright (C) 2015  Dark Storm
 * Copyright (C) 2022  Mibi88
 *
 * 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, see https://www.gnu.org/licenses/.
 */

#include "includes.h"

char* _itoa(int i, char b[])
{
    char const digit[] = "0123456789";
    char* p = b;
    if(i<0){
        *p++ = '-';
        i *= -1;
    }
    int shifter = i;
    do{ //Move to where representation ends
        ++p;
        shifter = shifter/10;
    }while(shifter);
    *p = '\0';
    do{ //Move back, inserting digits as u go
        *--p = digit[i%10];
        i = i/10;
    }while(i);
    return b;
}


#define PI 3.14159
#define M_PI_4 0.78539
#define FABS(x) ((x<0)?-x:x)

float _atan(float x)
{
	return (x * (M_PI_4 - ((FABS(x) - 1) * (0.2447 + 0.0663 * FABS(x)))));
}