| |
| /* |
| * 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. |
| */ |
| |
| /* |
| * ceil(x) |
| * Return x rounded toward -inf to integral value |
| * Method: |
| * Bit twiddling. |
| * Exception: |
| * Inexact flag raised if x not equal to ceil(x). |
| */ |
| |
| #include "fdlibm.h" |
| |
| #ifdef __STDC__ |
| static const double huge = 1.0e300; |
| #else |
| static double huge = 1.0e300; |
| #endif |
| |
| #ifdef __STDC__ |
| double ceil(double x) |
| #else |
| double ceil(x) |
| double x; |
| #endif |
| { |
| int i0,i1,j0; |
| unsigned i,j; |
| i0 = __HI(x); |
| i1 = __LO(x); |
| j0 = ((i0>>20)&0x7ff)-0x3ff; |
| if(j0<20) { |
| if(j0<0) { /* raise inexact if x != 0 */ |
| if(huge+x>0.0) {/* return 0*sign(x) if |x|<1 */ |
| if(i0<0) {i0=0x80000000;i1=0;} |
| else if((i0|i1)!=0) { i0=0x3ff00000;i1=0;} |
| } |
| } else { |
| i = (0x000fffff)>>j0; |
| if(((i0&i)|i1)==0) return x; /* x is integral */ |
| if(huge+x>0.0) { /* raise inexact flag */ |
| if(i0>0) i0 += (0x00100000)>>j0; |
| i0 &= (~i); i1=0; |
| } |
| } |
| } else if (j0>51) { |
| if(j0==0x400) return x+x; /* inf or NaN */ |
| else return x; /* x is integral */ |
| } else { |
| i = ((unsigned)(0xffffffff))>>(j0-20); |
| if((i1&i)==0) return x; /* x is integral */ |
| if(huge+x>0.0) { /* raise inexact flag */ |
| if(i0>0) { |
| if(j0==20) i0+=1; |
| else { |
| j = i1 + (1<<(52-j0)); |
| if(j<i1) i0+=1; /* got a carry */ |
| i1 = j; |
| } |
| } |
| i1 &= (~i); |
| } |
| } |
| __HI(x) = i0; |
| __LO(x) = i1; |
| return x; |
| } |
