| /* |
| * 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. |
| */ |
| |
| /* |
| * modf(double x, double *iptr) |
| * return fraction part of x, and return x's integral part in *iptr. |
| * Method: |
| * Bit twiddling. |
| * |
| * Exception: |
| * No exception. |
| */ |
| |
| #include "fdlibm.h" |
| |
| #ifdef __STDC__ |
| static const double one = 1.0; |
| #else |
| static double one = 1.0; |
| #endif |
| |
| #ifdef __STDC__ |
| double modf(double x, double *iptr) |
| #else |
| double modf(x, iptr) |
| double x,*iptr; |
| #endif |
| { |
| int i0,i1,j0; |
| unsigned i; |
| i0 = __HI(x); /* high x */ |
| i1 = __LO(x); /* low x */ |
| j0 = ((i0>>20)&0x7ff)-0x3ff; /* exponent of x */ |
| if(j0<20) { /* integer part in high x */ |
| if(j0<0) { /* |x|<1 */ |
| __HIp(iptr) = i0&0x80000000; |
| __LOp(iptr) = 0; /* *iptr = +-0 */ |
| return x; |
| } else { |
| i = (0x000fffff)>>j0; |
| if(((i0&i)|i1)==0) { /* x is integral */ |
| *iptr = x; |
| __HI(x) &= 0x80000000; |
| __LO(x) = 0; /* return +-0 */ |
| return x; |
| } else { |
| __HIp(iptr) = i0&(~i); |
| __LOp(iptr) = 0; |
| return x - *iptr; |
| } |
| } |
| } else if (j0>51) { /* no fraction part */ |
| *iptr = x*one; |
| __HI(x) &= 0x80000000; |
| __LO(x) = 0; /* return +-0 */ |
| return x; |
| } else { /* fraction part in low x */ |
| i = ((unsigned)(0xffffffff))>>(j0-20); |
| if((i1&i)==0) { /* x is integral */ |
| *iptr = x; |
| __HI(x) &= 0x80000000; |
| __LO(x) = 0; /* return +-0 */ |
| return x; |
| } else { |
| __HIp(iptr) = i0; |
| __LOp(iptr) = i1&(~i); |
| return x - *iptr; |
| } |
| } |
| } |
