1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
|
/* sf_nextafter.c -- float version of s_nextafter.c.
* Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
*/
/*
* ====================================================
* 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.
* ====================================================
*/
#include "fdlibm.h"
#ifdef __STDC__
float nextafterf(float x, float y)
#else
float nextafterf(x,y)
float x,y;
#endif
{
__int32_t hx,hy,ix,iy;
GET_FLOAT_WORD(hx,x);
GET_FLOAT_WORD(hy,y);
ix = hx&0x7fffffff; /* |x| */
iy = hy&0x7fffffff; /* |y| */
if(FLT_UWORD_IS_NAN(ix) ||
FLT_UWORD_IS_NAN(iy))
return x+y;
if(x==y) return y; /* x=y, return y */
if(FLT_UWORD_IS_ZERO(ix)) { /* x == 0 */
SET_FLOAT_WORD(x,(hy&0x80000000)|FLT_UWORD_MIN);
y = x*x;
if(y==x) return y; else return x; /* raise underflow flag */
}
if(hx>=0) { /* x > 0 */
if(hx>hy) { /* x > y, x -= ulp */
hx -= 1;
} else { /* x < y, x += ulp */
hx += 1;
}
} else { /* x < 0 */
if(hy>=0||hx>hy){ /* x < y, x -= ulp */
hx -= 1;
} else { /* x > y, x += ulp */
hx += 1;
}
}
hy = hx&0x7f800000;
if(hy>FLT_UWORD_MAX) return x+x; /* overflow */
if(hy<0x00800000) { /* underflow */
y = x*x;
if(y!=x) { /* raise underflow flag */
SET_FLOAT_WORD(y,hx);
return y;
}
}
SET_FLOAT_WORD(x,hx);
return x;
}
#ifdef _DOUBLE_IS_32BITS
#ifdef __STDC__
double nextafter(double x, double y)
#else
double nextafter(x,y)
double x,y;
#endif
{
return (double) nextafterf((float) x, (float) x);
}
#endif /* defined(_DOUBLE_IS_32BITS) */
|
