| /* s_nexttoward.c |
| * Conversion from s_nextafter.c by Ulrich Drepper, Cygnus Support, |
| * drepper@cygnus.com and Jakub Jelinek, jj@ultra.linux.cz. |
| */ |
| |
| /* |
| * ==================================================== |
| * 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 "math.h" |
| #include <math_private.h> |
| #include <float.h> |
| |
| #ifdef __STDC__ |
| double __nexttoward(double x, long double y) |
| #else |
| double __nexttoward(x,y) |
| double x; |
| long double y; |
| #endif |
| { |
| int32_t hx,ix; |
| int64_t hy,iy; |
| u_int32_t lx; |
| u_int64_t ly; |
| |
| EXTRACT_WORDS(hx,lx,x); |
| GET_LDOUBLE_WORDS64(hy,ly,y); |
| ix = hx&0x7fffffff; /* |x| */ |
| iy = hy&0x7fffffffffffffffLL; /* |y| */ |
| |
| if(((ix>=0x7ff00000)&&((ix-0x7ff00000)|lx)!=0) || /* x is nan */ |
| ((iy>=0x7fff000000000000LL)&&((iy-0x7fff000000000000LL)|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,(u_int32_t)((hy>>32)&0x80000000),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 (hy<0||(ix>>20)>(iy>>48)-0x3c00 |
| || ((ix>>20)==(iy>>48)-0x3c00 |
| && (((((int64_t)hx)<<28)|(lx>>4))>(hy&0x0000ffffffffffffLL) |
| || (((((int64_t)hx)<<28)|(lx>>4))==(hy&0x0000ffffffffffffLL) |
| && (lx&0xf)>(ly>>60))))) { /* 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||(ix>>20)>(iy>>48)-0x3c00 |
| || ((ix>>20)==(iy>>48)-0x3c00 |
| && (((((int64_t)hx)<<28)|(lx>>4))>(hy&0x0000ffffffffffffLL) |
| || (((((int64_t)hx)<<28)|(lx>>4))==(hy&0x0000ffffffffffffLL) |
| && (lx&0xf)>(ly>>60))))) { /* 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) |
| /* Force conversion to double. */ |
| asm ("" : "+m"(x)); |
| return x; |
| } |
| if(hy<0x00100000) { |
| double u = x*x; /* underflow */ |
| math_force_eval (u); /* raise underflow flag */ |
| } |
| INSERT_WORDS(x,hx,lx); |
| return x; |
| } |
| weak_alias (__nexttoward, nexttoward) |
