| |
| /* |
| * Copyright (c) 1998, 2001, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| /* __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 "fdlibm.h" |
| |
| #ifdef __STDC__ |
| static const double zero = 0.0; |
| #else |
| static double zero = 0.0; |
| #endif |
| |
| |
| #ifdef __STDC__ |
| double __ieee754_remainder(double x, double p) |
| #else |
| double __ieee754_remainder(x,p) |
| double x,p; |
| #endif |
| { |
| int hx,hp; |
| unsigned sx,lx,lp; |
| double p_half; |
| |
| hx = __HI(x); /* high word of x */ |
| lx = __LO(x); /* low word of x */ |
| hp = __HI(p); /* high word of p */ |
| lp = __LO(p); /* low word of 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; |
| } |
| } |
| __HI(x) ^= sx; |
| return x; |
| } |
