1 | /* s_nextafterf.c -- float version of s_nextafter.c. |
2 | */ |
3 | |
4 | /* |
5 | * ==================================================== |
6 | * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. |
7 | * |
8 | * Developed at SunPro, a Sun Microsystems, Inc. business. |
9 | * Permission to use, copy, modify, and distribute this |
10 | * software is freely granted, provided that this notice |
11 | * is preserved. |
12 | * ==================================================== |
13 | */ |
14 | |
15 | #if defined(LIBM_SCCS) && !defined(lint) |
16 | static char rcsid[] = "$NetBSD: s_nextafterf.c,v 1.4 1995/05/10 20:48:01 jtc Exp $" ; |
17 | #endif |
18 | |
19 | #include <errno.h> |
20 | #include <math.h> |
21 | #include <math-barriers.h> |
22 | #include <math_private.h> |
23 | #include <libm-alias-float.h> |
24 | #include <float.h> |
25 | |
26 | float __nextafterf(float x, float y) |
27 | { |
28 | int32_t hx,hy,ix,iy; |
29 | |
30 | GET_FLOAT_WORD(hx,x); |
31 | GET_FLOAT_WORD(hy,y); |
32 | ix = hx&0x7fffffff; /* |x| */ |
33 | iy = hy&0x7fffffff; /* |y| */ |
34 | |
35 | if((ix>0x7f800000) || /* x is nan */ |
36 | (iy>0x7f800000)) /* y is nan */ |
37 | return x+y; |
38 | if(x==y) return y; /* x=y, return y */ |
39 | if(ix==0) { /* x == 0 */ |
40 | float u; |
41 | SET_FLOAT_WORD(x,(hy&0x80000000)|1);/* return +-minsubnormal */ |
42 | u = math_opt_barrier (x); |
43 | u = u*u; |
44 | math_force_eval (u); /* raise underflow flag */ |
45 | return x; |
46 | } |
47 | if(hx>=0) { /* x > 0 */ |
48 | if(hx>hy) { /* x > y, x -= ulp */ |
49 | hx -= 1; |
50 | } else { /* x < y, x += ulp */ |
51 | hx += 1; |
52 | } |
53 | } else { /* x < 0 */ |
54 | if(hy>=0||hx>hy){ /* x < y, x -= ulp */ |
55 | hx -= 1; |
56 | } else { /* x > y, x += ulp */ |
57 | hx += 1; |
58 | } |
59 | } |
60 | hy = hx&0x7f800000; |
61 | if(hy>=0x7f800000) { |
62 | float u = x+x; /* overflow */ |
63 | math_force_eval (u); |
64 | __set_errno (ERANGE); |
65 | } |
66 | if(hy<0x00800000) { |
67 | float u = x*x; /* underflow */ |
68 | math_force_eval (u); /* raise underflow flag */ |
69 | __set_errno (ERANGE); |
70 | } |
71 | SET_FLOAT_WORD(x,hx); |
72 | return x; |
73 | } |
74 | libm_alias_float (__nextafter, nextafter) |
75 | |