1 | /* s_nextafterf.c -- float version of s_nextafter.c. |
2 | * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com. |
3 | */ |
4 | |
5 | /* |
6 | * ==================================================== |
7 | * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. |
8 | * |
9 | * Developed at SunPro, a Sun Microsystems, Inc. business. |
10 | * Permission to use, copy, modify, and distribute this |
11 | * software is freely granted, provided that this notice |
12 | * is preserved. |
13 | * ==================================================== |
14 | */ |
15 | |
16 | #if defined(LIBM_SCCS) && !defined(lint) |
17 | static char rcsid[] = "$NetBSD: s_nextafterf.c,v 1.4 1995/05/10 20:48:01 jtc Exp $" ; |
18 | #endif |
19 | |
20 | #include <errno.h> |
21 | #include <math.h> |
22 | #include <math_private.h> |
23 | #include <float.h> |
24 | |
25 | float __nextafterf(float x, float y) |
26 | { |
27 | int32_t hx,hy,ix,iy; |
28 | |
29 | GET_FLOAT_WORD(hx,x); |
30 | GET_FLOAT_WORD(hy,y); |
31 | ix = hx&0x7fffffff; /* |x| */ |
32 | iy = hy&0x7fffffff; /* |y| */ |
33 | |
34 | if((ix>0x7f800000) || /* x is nan */ |
35 | (iy>0x7f800000)) /* y is nan */ |
36 | return x+y; |
37 | if(x==y) return y; /* x=y, return y */ |
38 | if(ix==0) { /* x == 0 */ |
39 | float u; |
40 | SET_FLOAT_WORD(x,(hy&0x80000000)|1);/* return +-minsubnormal */ |
41 | u = math_opt_barrier (x); |
42 | u = u*u; |
43 | math_force_eval (u); /* raise underflow flag */ |
44 | return x; |
45 | } |
46 | if(hx>=0) { /* x > 0 */ |
47 | if(hx>hy) { /* x > y, x -= ulp */ |
48 | hx -= 1; |
49 | } else { /* x < y, x += ulp */ |
50 | hx += 1; |
51 | } |
52 | } else { /* x < 0 */ |
53 | if(hy>=0||hx>hy){ /* x < y, x -= ulp */ |
54 | hx -= 1; |
55 | } else { /* x > y, x += ulp */ |
56 | hx += 1; |
57 | } |
58 | } |
59 | hy = hx&0x7f800000; |
60 | if(hy>=0x7f800000) { |
61 | float u = x+x; /* overflow */ |
62 | math_force_eval (u); |
63 | __set_errno (ERANGE); |
64 | } |
65 | if(hy<0x00800000) { |
66 | float u = x*x; /* underflow */ |
67 | math_force_eval (u); /* raise underflow flag */ |
68 | __set_errno (ERANGE); |
69 | } |
70 | SET_FLOAT_WORD(x,hx); |
71 | return x; |
72 | } |
73 | weak_alias (__nextafterf, nextafterf) |
74 | |