Permalink
Cannot retrieve contributors at this time
Name already in use
A tag already exists with the provided branch name. Many Git commands accept both tag and branch names, so creating this branch may cause unexpected behavior. Are you sure you want to create this branch?
glibc/sysdeps/i386/fpu/s_nexttoward.c
Go to fileThis commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
93 lines (86 sloc)
2.32 KB
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
/* s_nexttoward.c | |
* Special i387 version | |
* Conversion from s_nextafter.c by Ulrich Drepper, Cygnus Support, | |
* drepper@cygnus.com. | |
*/ | |
/* | |
* ==================================================== | |
* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. | |
* | |
* Developed at SunPro, a Sun Microsystems, Inc. business. | |
* Permission to use, copy, modify, and distribute this | |
* software is freely granted, provided that this notice | |
* is preserved. | |
* ==================================================== | |
*/ | |
#if defined(LIBM_SCCS) && !defined(lint) | |
static char rcsid[] = "$NetBSD: $"; | |
#endif | |
/* IEEE functions | |
* nexttoward(x,y) | |
* return the next machine floating-point number of x in the | |
* direction toward y. | |
* Special cases: | |
*/ | |
#include <errno.h> | |
#include <math.h> | |
#include <math_private.h> | |
#include <float.h> | |
double __nexttoward(double x, long double y) | |
{ | |
int32_t hx,ix,iy; | |
u_int32_t lx,hy,ly,esy; | |
EXTRACT_WORDS(hx,lx,x); | |
GET_LDOUBLE_WORDS(esy,hy,ly,y); | |
ix = hx&0x7fffffff; /* |x| */ | |
iy = esy&0x7fff; /* |y| */ | |
/* Intel's extended format has the normally implicit 1 explicit | |
present. Sigh! */ | |
if(((ix>=0x7ff00000)&&((ix-0x7ff00000)|lx)!=0) || /* x is nan */ | |
((iy>=0x7fff)&&((hy&0x7fffffff)|ly)!=0)) /* y is nan */ | |
return x+y; | |
if((long double) x==y) return y; /* x=y, return y */ | |
if((ix|lx)==0) { /* x == 0 */ | |
double u; | |
INSERT_WORDS(x,(esy&0x8000)<<16,1); /* return +-minsub */ | |
u = math_opt_barrier (x); | |
u = u * u; | |
math_force_eval (u); /* raise underflow flag */ | |
return x; | |
} | |
if(hx>=0) { /* x > 0 */ | |
if (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 (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) { | |
double u = x+x; /* overflow */ | |
math_force_eval (u); | |
__set_errno (ERANGE); | |
} | |
if(hy<0x00100000) { | |
double u = x*x; /* underflow */ | |
math_force_eval (u); /* raise underflow flag */ | |
__set_errno (ERANGE); | |
} | |
INSERT_WORDS(x,hx,lx); | |
return x; | |
} | |
weak_alias (__nexttoward, nexttoward) | |
#ifdef NO_LONG_DOUBLE | |
strong_alias (__nexttoward, __nexttowardl) | |
weak_alias (__nexttoward, nexttowardl) | |
#endif |