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
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