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- /*
- * ====================================================
- * 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.
- * ====================================================
- */
- /* __ieee754_remainder(x,p)
- * Return :
- * returns x REM p = x - [x/p]*p as if in infinite
- * precise arithmetic, where [x/p] is the (infinite bit)
- * integer nearest x/p (in half way case choose the even one).
- * Method :
- * Based on fmod() return x-[x/p]chopped*p exactlp.
- */
- #include "math.h"
- #include "math_private.h"
- static const double zero = 0.0;
- double __ieee754_remainder(double x, double p)
- {
- int32_t hx,hp;
- u_int32_t sx,lx,lp;
- double p_half;
- EXTRACT_WORDS(hx,lx,x);
- EXTRACT_WORDS(hp,lp,p);
- sx = hx&0x80000000;
- hp &= 0x7fffffff;
- hx &= 0x7fffffff;
- /* purge off exception values */
- if((hp|lp)==0) return (x*p)/(x*p); /* p = 0 */
- if((hx>=0x7ff00000)|| /* x not finite */
- ((hp>=0x7ff00000)&& /* p is NaN */
- (((hp-0x7ff00000)|lp)!=0)))
- return (x*p)/(x*p);
- if (hp<=0x7fdfffff) x = __ieee754_fmod(x,p+p); /* now x < 2p */
- if (((hx-hp)|(lx-lp))==0) return zero*x;
- x = fabs(x);
- p = fabs(p);
- if (hp<0x00200000) {
- if(x+x>p) {
- x-=p;
- if(x+x>=p) x -= p;
- }
- } else {
- p_half = 0.5*p;
- if(x>p_half) {
- x-=p;
- if(x>=p_half) x -= p;
- }
- }
- GET_HIGH_WORD(hx,x);
- SET_HIGH_WORD(x,hx^sx);
- return x;
- }
- /*
- * wrapper remainder(x,p)
- */
- #ifndef _IEEE_LIBM
- double remainder(double x, double y)
- {
- double z = __ieee754_remainder(x, y);
- if (_LIB_VERSION == _IEEE_ || isnan(y))
- return z;
- if (y == 0.0)
- return __kernel_standard(x, y, 28); /* remainder(x,0) */
- return z;
- }
- strong_alias(remainder, drem)
- #else
- strong_alias(__ieee754_remainder, remainder)
- strong_alias(__ieee754_remainder, drem)
- #endif
- libm_hidden_def(remainder)
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