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 #include "math.h"
17 #include "math_private.h"
18
19 float
nextafterf(float x,float y)20 nextafterf(float x, float y)
21 {
22 int32_t hx,hy,ix,iy;
23
24 GET_FLOAT_WORD(hx,x);
25 GET_FLOAT_WORD(hy,y);
26 ix = hx&0x7fffffff; /* |x| */
27 iy = hy&0x7fffffff; /* |y| */
28
29 if((ix>0x7f800000) || /* x is nan */
30 (iy>0x7f800000)) /* y is nan */
31 return x+y;
32 if(x==y) return y; /* x=y, return y */
33 if(ix==0) { /* x == 0 */
34 SET_FLOAT_WORD(x,(hy&0x80000000)|1);/* return +-minsubnormal */
35 y = x*x;
36 if(y==x) return y; else return x; /* raise underflow flag */
37 }
38 if(hx>=0) { /* x > 0 */
39 if(hx>hy) { /* x > y, x -= ulp */
40 hx -= 1;
41 } else { /* x < y, x += ulp */
42 hx += 1;
43 }
44 } else { /* x < 0 */
45 if(hy>=0||hx>hy){ /* x < y, x -= ulp */
46 hx -= 1;
47 } else { /* x > y, x += ulp */
48 hx += 1;
49 }
50 }
51 hy = hx&0x7f800000;
52 if(hy>=0x7f800000) return x+x; /* overflow */
53 if(hy<0x00800000) { /* underflow */
54 y = x*x;
55 if(y!=x) { /* raise underflow flag */
56 SET_FLOAT_WORD(y,hx);
57 return y;
58 }
59 }
60 SET_FLOAT_WORD(x,hx);
61 return x;
62 }
63