1/*
2 * ====================================================
3 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
4 *
5 * Developed at SunPro, a Sun Microsystems, Inc. business.
6 * Permission to use, copy, modify, and distribute this
7 * software is freely granted, provided that this notice
8 * is preserved.
9 * ====================================================
10 */
11
12#include <sys/cdefs.h>
13__FBSDID("$FreeBSD$");
14
15#include <float.h>
16
17#include "fpmath.h"
18#include "math.h"
19#include "math_private.h"
20
21#define	LDBL_INFNAN_EXP	(LDBL_MAX_EXP * 2 - 1)
22
23float
24nexttowardf(float x, long double y)
25{
26	union IEEEl2bits uy;
27	volatile float t;
28	int32_t hx,ix;
29
30	GET_FLOAT_WORD(hx,x);
31	ix = hx&0x7fffffff;		/* |x| */
32	uy.e = y;
33
34	if((ix>0x7f800000) ||
35	   (uy.bits.exp == LDBL_INFNAN_EXP &&
36	    ((uy.bits.manh&~LDBL_NBIT)|uy.bits.manl) != 0))
37	   return x+y;	/* x or y is nan */
38	if(x==y) return (float)y;		/* x=y, return y */
39	if(ix==0) {				/* x == 0 */
40	    SET_FLOAT_WORD(x,(uy.bits.sign<<31)|1);/* return +-minsubnormal */
41	    t = x*x;
42	    if(t==x) return t; else return x;	/* raise underflow flag */
43	}
44	if(hx>=0 ^ x < y)			/* x -= ulp */
45	    hx -= 1;
46	else					/* x += ulp */
47	    hx += 1;
48	ix = hx&0x7f800000;
49	if(ix>=0x7f800000) return x+x;	/* overflow  */
50	if(ix<0x00800000) {		/* underflow */
51	    t = x*x;
52	    if(t!=x) {		/* raise underflow flag */
53	        SET_FLOAT_WORD(x,hx);
54		return x;
55	    }
56	}
57	SET_FLOAT_WORD(x,hx);
58	return x;
59}
60