| |
| /* |
| * 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. |
| */ |
| |
| /* IEEE functions |
| * nextafter(x,y) |
| * return the next machine floating-point number of x in the |
| * direction toward y. |
| * Special cases: |
| */ |
| |
| #include "fdlibm.h" |
| |
| #ifdef __STDC__ |
| double nextafter(double x, double y) |
| #else |
| double nextafter(x,y) |
| double x,y; |
| #endif |
| { |
| int hx,hy,ix,iy; |
| unsigned lx,ly; |
| |
| hx = __HI(x); /* high word of x */ |
| lx = __LO(x); /* low word of x */ |
| hy = __HI(y); /* high word of y */ |
| ly = __LO(y); /* low word of y */ |
| ix = hx&0x7fffffff; /* |x| */ |
| iy = hy&0x7fffffff; /* |y| */ |
| |
| if(((ix>=0x7ff00000)&&((ix-0x7ff00000)|lx)!=0) || /* x is nan */ |
| ((iy>=0x7ff00000)&&((iy-0x7ff00000)|ly)!=0)) /* y is nan */ |
| return x+y; |
| if(x==y) return x; /* x=y, return x */ |
| if((ix|lx)==0) { /* x == 0 */ |
| __HI(x) = hy&0x80000000; /* return +-minsubnormal */ |
| __LO(x) = 1; |
| y = x*x; |
| if(y==x) return y; else return x; /* raise underflow flag */ |
| } |
| if(hx>=0) { /* x > 0 */ |
| if(hx>hy||((hx==hy)&&(lx>ly))) { /* x > y, x -= ulp */ |
| if(lx==0) hx -= 1; |
| lx -= 1; |
| } else { /* x < y, x += ulp */ |
| lx += 1; |
| if(lx==0) hx += 1; |
| } |
| } else { /* x < 0 */ |
| if(hy>=0||hx>hy||((hx==hy)&&(lx>ly))){/* x < y, x -= ulp */ |
| if(lx==0) hx -= 1; |
| lx -= 1; |
| } else { /* x > y, x += ulp */ |
| lx += 1; |
| if(lx==0) hx += 1; |
| } |
| } |
| hy = hx&0x7ff00000; |
| if(hy>=0x7ff00000) return x+x; /* overflow */ |
| if(hy<0x00100000) { /* underflow */ |
| y = x*x; |
| if(y!=x) { /* raise underflow flag */ |
| __HI(y) = hx; __LO(y) = lx; |
| return y; |
| } |
| } |
| __HI(x) = hx; __LO(x) = lx; |
| return x; |
| } |
