path: root/src/math/e_remainderf.c

/* e_remainderf.c -- float version of e_remainder.c.
 * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
 */

/*
 * ====================================================
 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
 *
 * Developed at SunPro, a Sun Microsystems, Inc. business.
 * Permission to use, copy, modify, and distribute this
 * software is freely granted, provided that this notice
 * is preserved.
 * ====================================================
 */

#include <math.h>
#include "math_private.h"

static const float zero = 0.0;


float
remainderf(float x, float p)
{
        int32_t hx,hp;
        uint32_t sx;
        float p_half;

        GET_FLOAT_WORD(hx,x);
        GET_FLOAT_WORD(hp,p);
        sx = hx&0x80000000;
        hp &= 0x7fffffff;
        hx &= 0x7fffffff;

    /* purge off exception values */
        if(hp==0) return (x*p)/(x*p);           /* p = 0 */
        if((hx>=0x7f800000)||                   /* x not finite */
          ((hp>0x7f800000)))                    /* p is NaN */
            return (x*p)/(x*p);


        if (hp<=0x7effffff) x = fmodf(x,p+p); /* now x < 2p */
        if ((hx-hp)==0) return zero*x;
        x  = fabsf(x);
        p  = fabsf(p);
        if (hp<0x01000000) {
            if(x+x>p) {
                x-=p;
                if(x+x>=p) x -= p;
            }
        } else {
            p_half = (float)0.5*p;
            if(x>p_half) {
                x-=p;
                if(x>=p_half) x -= p;
            }
        }
        GET_FLOAT_WORD(hx,x);
        SET_FLOAT_WORD(x,hx^sx);
        return x;
}