projects / thirdparty / glibc.git / blame
| Commit | Line | Data |
|---|---|---|
| f7eac6eb RM |
1 | /* @(#)s_nextafter.c 5.1 93/09/24 */ |
| 2 | /* | |
| 3 | * ==================================================== | |
| 4 | * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. | |
| 5 | * | |
| 6 | * Developed at SunPro, a Sun Microsystems, Inc. business. | |
| 7 | * Permission to use, copy, modify, and distribute this | |
| cccda09f | 8 | * software is freely granted, provided that this notice |
| f7eac6eb RM |
9 | * is preserved. |
| 10 | * ==================================================== | |
| 11 | */ | |
| 12 | ||
| 13 | #if defined(LIBM_SCCS) && !defined(lint) | |
| 14 | static char rcsid[] = "$NetBSD: s_nextafter.c,v 1.8 1995/05/10 20:47:58 jtc Exp $"; | |
| 15 | #endif | |
| 16 | ||
| 17 | /* IEEE functions | |
| 18 | * nextafter(x,y) | |
| 19 | * return the next machine floating-point number of x in the | |
| 20 | * direction toward y. | |
| 21 | * Special cases: | |
| 22 | */ | |
| 23 | ||
| 249fd241 UD |
24 | /* Ugly hack so that the aliasing works. */ |
| 25 | #define __nexttoward __internal___nexttoward | |
| 26 | #define nexttoward __internal_nexttoward | |
| 27 | ||
| f7eac6eb RM |
28 | #include "math.h" |
| 29 | #include "math_private.h" | |
| 30 | ||
| 31 | #ifdef __STDC__ | |
| 32 | double __nextafter(double x, double y) | |
| 33 | #else | |
| 34 | double __nextafter(x,y) | |
| 35 | double x,y; | |
| 36 | #endif | |
| 37 | { | |
| 38 | int32_t hx,hy,ix,iy; | |
| 39 | u_int32_t lx,ly; | |
| 40 | ||
| 41 | EXTRACT_WORDS(hx,lx,x); | |
| 42 | EXTRACT_WORDS(hy,ly,y); | |
| 43 | ix = hx&0x7fffffff; /* |x| */ | |
| 44 | iy = hy&0x7fffffff; /* |y| */ | |
| 45 | ||
| cccda09f UD |
46 | if(((ix>=0x7ff00000)&&((ix-0x7ff00000)|lx)!=0) || /* x is nan */ |
| 47 | ((iy>=0x7ff00000)&&((iy-0x7ff00000)|ly)!=0)) /* y is nan */ | |
| 48 | return x+y; | |
| bc9f6000 | 49 | if(x==y) return y; /* x=y, return y */ |
| f7eac6eb RM |
50 | if((ix|lx)==0) { /* x == 0 */ |
| 51 | INSERT_WORDS(x,hy&0x80000000,1); /* return +-minsubnormal */ | |
| 52 | y = x*x; | |
| 53 | if(y==x) return y; else return x; /* raise underflow flag */ | |
| cccda09f | 54 | } |
| f7eac6eb RM |
55 | if(hx>=0) { /* x > 0 */ |
| 56 | if(hx>hy||((hx==hy)&&(lx>ly))) { /* x > y, x -= ulp */ | |
| 57 | if(lx==0) hx -= 1; | |
| 58 | lx -= 1; | |
| 59 | } else { /* x < y, x += ulp */ | |
| 60 | lx += 1; | |
| 61 | if(lx==0) hx += 1; | |
| 62 | } | |
| 63 | } else { /* x < 0 */ | |
| 64 | if(hy>=0||hx>hy||((hx==hy)&&(lx>ly))){/* x < y, x -= ulp */ | |
| 65 | if(lx==0) hx -= 1; | |
| 66 | lx -= 1; | |
| 67 | } else { /* x > y, x += ulp */ | |
| 68 | lx += 1; | |
| 69 | if(lx==0) hx += 1; | |
| 70 | } | |
| 71 | } | |
| 72 | hy = hx&0x7ff00000; | |
| 73 | if(hy>=0x7ff00000) return x+x; /* overflow */ | |
| 74 | if(hy<0x00100000) { /* underflow */ | |
| 75 | y = x*x; | |
| 76 | if(y!=x) { /* raise underflow flag */ | |
| 77 | INSERT_WORDS(y,hx,lx); | |
| 78 | return y; | |
| 79 | } | |
| 80 | } | |
| 81 | INSERT_WORDS(x,hx,lx); | |
| 82 | return x; | |
| 83 | } | |
| 84 | weak_alias (__nextafter, nextafter) | |
| cccda09f UD |
85 | #ifdef NO_LONG_DOUBLE |
| 86 | strong_alias (__nextafter, __nextafterl) | |
| 87 | weak_alias (__nextafter, nextafterl) | |
| 90dd37a6 AJ |
88 | strong_alias (__nextafter, __nexttowardl) |
| 89 | weak_alias (__nexttowardl, nexttowardl) | |
| d03db7f0 | 90 | #undef __nexttoward |
| abfbdde1 | 91 | strong_alias (__nextafter, __nexttoward) |
| d03db7f0 | 92 | #undef nexttoward |
| abfbdde1 | 93 | weak_alias (__nextafter, nexttoward) |
| cccda09f | 94 | #endif |