newlib-cygwin/newlib/libm/math/ef_remainder.c

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2000-02-18 03:39:52 +08:00
/* ef_remainder.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 "fdlibm.h"
#ifdef __STDC__
static const float zero = 0.0;
#else
static float zero = 0.0;
#endif
#ifdef __STDC__
float __ieee754_remainderf(float x, float p)
#else
float __ieee754_remainderf(x,p)
float x,p;
#endif
{
__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(FLT_UWORD_IS_ZERO(hp)||
!FLT_UWORD_IS_FINITE(hx)||
FLT_UWORD_IS_NAN(hp))
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return (x*p)/(x*p);
if (hp<=FLT_UWORD_HALF_MAX) x = __ieee754_fmodf(x,p+p); /* now x < 2p */
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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;
}