(__ieee754_sqrt): Remove unused variables b and n.
[kopensolaris-gnu/glibc.git] / sysdeps / ieee754 / ldbl-96 / s_nexttoward.c
1 /* s_nexttoward.c
2  * Conversion from s_nextafter.c by Ulrich Drepper, Cygnus Support,
3  * drepper@cygnus.com.
4  */
5
6 /*
7  * ====================================================
8  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
9  *
10  * Developed at SunPro, a Sun Microsystems, Inc. business.
11  * Permission to use, copy, modify, and distribute this
12  * software is freely granted, provided that this notice
13  * is preserved.
14  * ====================================================
15  */
16
17 #if defined(LIBM_SCCS) && !defined(lint)
18 static char rcsid[] = "$NetBSD: $";
19 #endif
20
21 /* IEEE functions
22  *      nexttoward(x,y)
23  *      return the next machine floating-point number of x in the
24  *      direction toward y.
25  *   Special cases:
26  */
27
28 #include "math.h"
29 #include "math_private.h"
30
31 #ifdef __STDC__
32         double __nexttoward(double x, long double y)
33 #else
34         double __nexttoward(x,y)
35         double x;
36         long double y;
37 #endif
38 {
39         int32_t hx,ix,iy;
40         u_int32_t lx,hy,ly,esy;
41
42         EXTRACT_WORDS(hx,lx,x);
43         GET_LDOUBLE_WORDS(esy,hy,ly,y);
44         ix = hx&0x7fffffff;             /* |x| */
45         iy = esy&0x7fff;                /* |y| */
46
47         if(((ix>=0x7ff00000)&&((ix-0x7ff00000)|lx)!=0) ||   /* x is nan */
48            ((iy>=0x7fff)&&((hy|ly)|-(hy|ly))!=0))           /* y is nan */
49            return x+y;
50         if((long double) x==y) return y;        /* x=y, return y */
51         if((ix|lx)==0) {                        /* x == 0 */
52             double x2;
53             INSERT_WORDS(x,esy&0x8000?0x80000000:0,1);/* return +-minsub */
54             x2 = x*x;
55             if(x2==x) return x2; else return x; /* raise underflow flag */
56         }
57         if(hx>=0) {                             /* x > 0 */
58             if (esy>=0x8000||((ix>>20)&0x7ff)>iy-0x3c00
59                 || (((ix>>20)&0x7ff)==iy-0x3c00
60                     && (((hx<<11)|(lx>>21))>(hy&0x7fffffff)
61                         || (((hx<<11)|(lx>>21))==(hy&0x7fffffff)
62                             && (lx<<11)>ly)))) {        /* x > y, x -= ulp */
63                 if(lx==0) hx -= 1;
64                 lx -= 1;
65             } else {                            /* x < y, x += ulp */
66                 lx += 1;
67                 if(lx==0) hx += 1;
68             }
69         } else {                                /* x < 0 */
70             if (esy<0x8000||((ix>>20)&0x7ff)>iy-0x3c00
71                 || (((ix>>20)&0x7ff)==iy-0x3c00
72                     && (((hx<<11)|(lx>>21))>(hy&0x7fffffff)
73                         || (((hx<<11)|(lx>>21))==(hy&0x7fffffff)
74                             && (lx<<11)>ly))))  {/* x < y, x -= ulp */
75                 if(lx==0) hx -= 1;
76                 lx -= 1;
77             } else {                            /* x > y, x += ulp */
78                 lx += 1;
79                 if(lx==0) hx += 1;
80             }
81         }
82         hy = hx&0x7ff00000;
83         if(hy>=0x7ff00000) return x+x;  /* overflow  */
84         if(hy<0x00100000) {             /* underflow */
85             double x2 = x*x;
86             if(x2!=x) {         /* raise underflow flag */
87                 INSERT_WORDS(x2,hx,lx);
88                 return x2;
89             }
90         }
91         INSERT_WORDS(x,hx,lx);
92         return x;
93 }
94 weak_alias (__nexttoward, nexttoward)
95 #ifdef NO_LONG_DOUBLE
96 strong_alias (__nexttoward, __nexttowardl)
97 weak_alias (__nexttoward, nexttowardl)
98 #endif