diff options
Diffstat (limited to 'lib/msun/src/e_remainder.c')
-rw-r--r-- | lib/msun/src/e_remainder.c | 79 |
1 files changed, 79 insertions, 0 deletions
diff --git a/lib/msun/src/e_remainder.c b/lib/msun/src/e_remainder.c new file mode 100644 index 0000000..9be513b --- /dev/null +++ b/lib/msun/src/e_remainder.c @@ -0,0 +1,79 @@ + +/* @(#)e_remainder.c 1.3 95/01/18 */ +/* + * ==================================================== + * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. + * + * Developed at SunSoft, a Sun Microsystems, Inc. business. + * Permission to use, copy, modify, and distribute this + * software is freely granted, provided that this notice + * is preserved. + * ==================================================== + */ + +#include <sys/cdefs.h> +__FBSDID("$FreeBSD$"); + +/* __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 <float.h> + +#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 ((long double)x*p)/((long double)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); + if ((hx&0x7fffffff)==0) hx = 0; + SET_HIGH_WORD(x,hx^sx); + return x; +} + +#if LDBL_MANT_DIG == 53 +__weak_reference(remainder, remainderl); +#endif |