POK
/home/jaouen/pok_official/pok/trunk/libpok/libm/e_remainderf.c
00001 /*
00002  *                               POK header
00003  * 
00004  * The following file is a part of the POK project. Any modification should
00005  * made according to the POK licence. You CANNOT use this file or a part of
00006  * this file is this part of a file for your own project
00007  *
00008  * For more information on the POK licence, please see our LICENCE FILE
00009  *
00010  * Please follow the coding guidelines described in doc/CODING_GUIDELINES
00011  *
00012  *                                      Copyright (c) 2007-2009 POK team 
00013  *
00014  * Created by julien on Fri Jan 30 14:41:34 2009 
00015  */
00016 
00017 /* e_remainderf.c -- float version of e_remainder.c.
00018  * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
00019  */
00020 
00021 /*
00022  * ====================================================
00023  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
00024  *
00025  * Developed at SunPro, a Sun Microsystems, Inc. business.
00026  * Permission to use, copy, modify, and distribute this
00027  * software is freely granted, provided that this notice
00028  * is preserved.
00029  * ====================================================
00030  */
00031 
00032 #ifdef POK_NEEDS_LIBMATH
00033 
00034 #include <libm.h>
00035 #include "math_private.h"
00036 
00037 static const float zero = 0.0;
00038 
00039 
00040 float
00041 __ieee754_remainderf(float x, float p)
00042 {
00043         int32_t hx,hp;
00044         uint32_t sx;
00045         float p_half;
00046 
00047         GET_FLOAT_WORD(hx,x);
00048         GET_FLOAT_WORD(hp,p);
00049         sx = hx&0x80000000;
00050         hp &= 0x7fffffff;
00051         hx &= 0x7fffffff;
00052 
00053     /* purge off exception values */
00054         if(hp==0) return (x*p)/(x*p);           /* p = 0 */
00055         if((hx>=0x7f800000)||                   /* x not finite */
00056           ((hp>0x7f800000)))                    /* p is NaN */
00057             return (x*p)/(x*p);
00058 
00059 
00060         if (hp<=0x7effffff) x = __ieee754_fmodf(x,p+p); /* now x < 2p */
00061         if ((hx-hp)==0) return zero*x;
00062         x  = fabsf(x);
00063         p  = fabsf(p);
00064         if (hp<0x01000000) {
00065             if(x+x>p) {
00066                 x-=p;
00067                 if(x+x>=p) x -= p;
00068             }
00069         } else {
00070             p_half = (float)0.5*p;
00071             if(x>p_half) {
00072                 x-=p;
00073                 if(x>=p_half) x -= p;
00074             }
00075         }
00076         GET_FLOAT_WORD(hx,x);
00077         SET_FLOAT_WORD(x,hx^sx);
00078         return x;
00079 }
00080 #endif