diff options
Diffstat (limited to 'math/s_nextafter.c')
| -rw-r--r-- | math/s_nextafter.c | 100 |
1 files changed, 100 insertions, 0 deletions
diff --git a/math/s_nextafter.c b/math/s_nextafter.c new file mode 100644 index 0000000..d2af52d --- /dev/null +++ b/math/s_nextafter.c @@ -0,0 +1,100 @@ +/* @(#)s_nextafter.c 5.1 93/09/24 */ +/* + * ==================================================== + * 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: s_nextafter.c,v 1.8 1995/05/10 20:47:58 jtc Exp $"; +#endif + +/* IEEE functions + * nextafter(x,y) + * return the next machine floating-point number of x in the + * direction toward y. + * Special cases: + */ + +/* Ugly hack so that the aliasing works. */ +#define __nexttoward __internal___nexttoward +#define nexttoward __internal_nexttoward + +#include <math.h> +#include <math_private.h> +#include <float.h> + +#ifdef __STDC__ + double __nextafter(double x, double y) +#else + double __nextafter(x,y) + double x,y; +#endif +{ + int32_t hx,hy,ix,iy; + u_int32_t lx,ly; + + EXTRACT_WORDS(hx,lx,x); + EXTRACT_WORDS(hy,ly,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 y; /* x=y, return y */ + if((ix|lx)==0) { /* x == 0 */ + double u; + INSERT_WORDS(x,hy&0x80000000,1); /* return +-minsubnormal */ + u = math_opt_barrier (x); + u = u*u; + math_force_eval (u); /* raise underflow flag */ + return x; + } + 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) { + x = x+x; /* overflow */ + if (FLT_EVAL_METHOD != 0 && FLT_EVAL_METHOD != 1) + asm ("" : "+m"(x)); + return x; /* overflow */ + } + if(hy<0x00100000) { + double u = x*x; /* underflow */ + math_force_eval (u); /* raise underflow flag */ + } + INSERT_WORDS(x,hx,lx); + return x; +} +weak_alias (__nextafter, nextafter) +#ifdef NO_LONG_DOUBLE +strong_alias (__nextafter, __nextafterl) +weak_alias (__nextafter, nextafterl) +strong_alias (__nextafter, __nexttowardl) +weak_alias (__nexttowardl, nexttowardl) +#undef __nexttoward +strong_alias (__nextafter, __nexttoward) +#undef nexttoward +weak_alias (__nextafter, nexttoward) +#endif |