/*============================================================================
  NuSYSTEM sample program SNAKE TAIL HACK
  
  math.c
  
  Copyright (C) 1997, NINTENDO Co,Ltd.
  ============================================================================*/

#include <ultra64.h>
#include <assert.h>

#include <math.h>

#define NRECTAB 100
static float reciprocal_table_f[NRECTAB] = {
    0,1.0/1.0,1.0/2.0,1.0/3.0,1.0/4.0,1.0/5.0,1.0/6.0,1.0/7.0,1.0/8.0,1.0/9.0,1.0/10.0,
    1.0/11.0,1.0/12.0,1.0/13.0,1.0/14.0,1.0/15.0,1.0/16.0,1.0/17.0,1.0/18.0,1.0/19.0,1.0/20.0,
    1.0/21.0,1.0/22.0,1.0/23.0,1.0/24.0,1.0/25.0,1.0/26.0,1.0/27.0,1.0/28.0,1.0/29.0,1.0/30.0,
    1.0/31.0,1.0/32.0,1.0/33.0,1.0/34.0,1.0/35.0,1.0/36.0,1.0/37.0,1.0/38.0,1.0/39.0,1.0/40.0,
    1.0/41.0,1.0/42.0,1.0/43.0,1.0/44.0,1.0/45.0,1.0/46.0,1.0/47.0,1.0/48.0,1.0/49.0,1.0/50.0,
    1.0/51.0,1.0/52.0,1.0/53.0,1.0/54.0,1.0/55.0,1.0/56.0,1.0/57.0,1.0/58.0,1.0/59.0,1.0/60.0,
    1.0/61.0,1.0/62.0,1.0/63.0,1.0/64.0,1.0/65.0,1.0/66.0,1.0/67.0,1.0/68.0,1.0/69.0,1.0/70.0,
    1.0/71.0,1.0/72.0,1.0/73.0,1.0/74.0,1.0/75.0,1.0/76.0,1.0/77.0,1.0/78.0,1.0/79.0,1.0/80.0,
    1.0/81.0,1.0/82.0,1.0/83.0,1.0/84.0,1.0/85.0,1.0/86.0,1.0/87.0,1.0/88.0,1.0/89.0,1.0/90.0,
    1.0/91.0,1.0/92.0,1.0/93.0,1.0/94.0,1.0/95.0,1.0/96.0,1.0/97.0,1.0/89.0,1.0/99.0
};


float
atan2bodyf(float y,float x)
{ 
    float arg,ys,old;
    float power, term, sum, z;
    int i;

    if ( y == 0.0f )
      return 0.0f;

    if ( x == 0.0f )
      return (y > 0.0f)? (float)M_PI_2 : -(float)M_PI_2;

    arg = y / x;

    if ( arg == 1.0f )
      return (y > 0.0f)? (float)M_PI_4 : -3.0f * (float)M_PI_4;
 
    if ( arg == -1.0f )
      return (x > 0.0f) ? -(float)M_PI_4 :  3.0f * (float)M_PI_4;

    if ( arg > 1.0f || arg < -1.0f) {
	sum = atan2bodyf(x, y);
	if( x > 0.0f )
	  return (float)M_PI_2 - sum;
	else         
	  return (y > 0.0f) ? (float)M_PI_2 - sum: -3.0f * (float)M_PI_2 -sum;
    }

    ys = arg * arg;
    old = 1.0f / (1.0f + ys);
    z = ys * old;
    sum = 1.0f;
    i = 4;
    power = z * 2.0f / 3.0f;
    while( i < NRECTAB-1) {
	term = power;
	sum += term;
	if ( term >= -TOL && term <= TOL) break;
	power *= ( z * (float)i * reciprocal_table_f[i+1] );
	i += 2;
    }
    sum *= arg * old;
    return ( x > 0.0f )? sum : ( y > 0.0f ) ? (float)M_PI + sum :-(float)M_PI + sum;
}

float
Atan2f(float y, float x)
{
    return atan2bodyf(y, x) * (float)M_RTOD;
}

/*-----------------------------------------------------------------------------
  Return the absolute value
  -----------------------------------------------------------------------------*/
s8
Zettai( s8 num )
{
    if(num < 0){
	return(-num);
    }else{
	return(num);
    }
}