1/* s_nexttowardf.c -- float version of s_nextafter.c.
2 * Special i387 version.
3 * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
4 */
5
6/*
7 * ====================================================
8 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
9 *
10 * Developed at SunPro, a Sun Microsystems, Inc. business.
11 * Permission to use, copy, modify, and distribute this
12 * software is freely granted, provided that this notice
13 * is preserved.
14 * ====================================================
15 */
16
17#if defined(LIBM_SCCS) && !defined(lint)
18static char rcsid[] = "$NetBSD: $";
19#endif
20
21#include "math.h"
22#include "math_private.h"
23
24#ifdef __STDC__
25	float __nexttowardf(float x, long double y)
26#else
27	float __nexttowardf(x,y)
28	float x;
29	long double y;
30#endif
31{
32	int32_t hx,ix,iy;
33	u_int32_t hy,ly,esy;
34
35	GET_FLOAT_WORD(hx,x);
36	GET_LDOUBLE_WORDS(esy,hy,ly,y);
37	ix = hx&0x7fffffff;		/* |x| */
38	iy = esy&0x7fff;		/* |y| */
39
40	/* Intel's extended format has the normally implicit 1 explicit
41	   present.  Sigh!  */
42	if((ix>0x7f800000) ||			/* x is nan */
43	   (iy>=0x7fff&&(((hy&0x7fffffff)|ly)!=0))) /* y is nan */
44	   return x+y;
45	if((long double) x==y) return y;	/* x=y, return y */
46	if(ix==0) {				/* x == 0 */
47	    float x2;
48	    SET_FLOAT_WORD(x,((esy&0x8000)<<16)|1);/* return +-minsub*/
49	    x2 = x*x;
50	    if(x2==x) return x2; else return x;	/* raise underflow flag */
51	}
52	if(hx>=0) {				/* x > 0 */
53	    if(esy>=0x8000||((ix>>23)&0xff)>iy-0x3f80
54	       || (((ix>>23)&0xff)==iy-0x3f80
55		   && ((ix&0x7fffff)<<8)>(hy&0x7fffffff))) {/* x > y, x -= ulp */
56		hx -= 1;
57	    } else {				/* x < y, x += ulp */
58		hx += 1;
59	    }
60	} else {				/* x < 0 */
61	    if(esy<0x8000||((ix>>23)&0xff)>iy-0x3f80
62	       || (((ix>>23)&0xff)==iy-0x3f80
63		   && ((ix&0x7fffff)<<8)>(hy&0x7fffffff))) {/* x < y, x -= ulp */
64		hx -= 1;
65	    } else {				/* x > y, x += ulp */
66		hx += 1;
67	    }
68	}
69	hy = hx&0x7f800000;
70	if(hy>=0x7f800000) {
71	  x = x+x;	/* overflow  */
72	  /* Force conversion to float.  */
73	  asm ("" : "=m"(x) : "m"(x));
74	  return x;
75	}
76	if(hy<0x00800000) {		/* underflow */
77	    float x2 = x*x;
78	    if(x2!=x) {		/* raise underflow flag */
79	        SET_FLOAT_WORD(x2,hx);
80		return x2;
81	    }
82	}
83	SET_FLOAT_WORD(x,hx);
84	return x;
85}
86weak_alias (__nexttowardf, nexttowardf)
87