1/*      $NetBSD: n_floor.c,v 1.9 2024/05/08 02:08:11 riastradh Exp $ */
2/*
3 * Copyright (c) 1985, 1993
4 *	The Regents of the University of California.  All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 * 3. Neither the name of the University nor the names of its contributors
15 *    may be used to endorse or promote products derived from this software
16 *    without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 */
30
31#ifndef lint
32#if 0
33static char sccsid[] = "@(#)floor.c	8.1 (Berkeley) 6/4/93";
34#endif
35#endif /* not lint */
36
37#define _LIBM_STATIC
38#include "mathimpl.h"
39
40vc(L, 4503599627370496.0E0 ,0000,5c00,0000,0000, 55, 1.0) /* 2**55 */
41
42ic(L, 4503599627370496.0E0, 52, 1.0)			  /* 2**52 */
43
44#ifdef vccast
45#define	L	vccast(L)
46#endif
47
48__weak_alias(ceill, ceil)
49__weak_alias(floorl, floor)
50__weak_alias(truncl, trunc)
51__weak_alias(rintl, rint)
52
53/*
54 * floor(x) := the largest integer no larger than x;
55 * ceil(x) := -floor(-x), for all real x.
56 *
57 * Note: Inexact will be signaled if x is not an integer, as is
58 *	customary for IEEE 754.  No other signal can be emitted.
59 */
60double
61floor(double x)
62{
63	volatile double y;
64
65	if (
66#if !defined(__vax__)&&!defined(tahoe)
67		x != x ||	/* NaN */
68#endif	/* !defined(__vax__)&&!defined(tahoe) */
69		x >= L)		/* already an even integer */
70		return x;
71	else if (x < (double)0)
72		return -ceil(-x);
73	else {			/* now 0 <= x < L */
74		y = L+x;		/* destructive store must be forced */
75		y -= L;			/* an integer, and |x-y| < 1 */
76		return x < y ? y-(double)1 : y;
77	}
78}
79
80float
81floorf(float x)
82{
83	return floor((double)x);
84}
85
86double
87ceil(double x)
88{
89	volatile double y;
90
91	if (
92#if !defined(__vax__)&&!defined(tahoe)
93		x != x ||	/* NaN */
94#endif	/* !defined(__vax__)&&!defined(tahoe) */
95		x >= L)		/* already an even integer */
96		return x;
97	else if (x < (double)0)
98		return -floor(-x);
99	else {			/* now 0 <= x < L */
100		y = L+x;		/* destructive store must be forced */
101		y -= L;			/* an integer, and |x-y| < 1 */
102		return x > y ? y+(double)1 : y;
103	}
104}
105
106float
107ceilf(float x)
108{
109	return ceil((double)x);
110}
111
112/*
113 * algorithm for rint(x) in pseudo-pascal form ...
114 *
115 * real rint(x): real x;
116 *	... delivers integer nearest x in direction of prevailing rounding
117 *	... mode
118 * const	L = (last consecutive integer)/2
119 * 	  = 2**55; for VAX D
120 * 	  = 2**52; for IEEE 754 Double
121 * real	s,t;
122 * begin
123 * 	if x != x then return x;		... NaN
124 * 	if |x| >= L then return x;		... already an integer
125 * 	s := copysign(L,x);
126 * 	t := x + s;				... = (x+s) rounded to integer
127 * 	return t - s
128 * end;
129 *
130 * Note: Inexact will be signaled if x is not an integer, as is
131 *	customary for IEEE 754.  No other signal can be emitted.
132 */
133double
134rint(double x)
135{
136	double s;
137	volatile double t;
138	const double one = 1.0;
139
140#if !defined(__vax__)&&!defined(tahoe)
141	if (x != x)				/* NaN */
142		return (x);
143#endif	/* !defined(__vax__)&&!defined(tahoe) */
144	if (copysign(x,one) >= L)		/* already an integer */
145	    return (x);
146	s = copysign(L,x);
147	t = x + s;				/* x+s rounded to integer */
148	return (t - s);
149}
150
151float
152rintf(float x)
153{
154	return rint((double)x);
155}
156
157long
158lrint(double x)
159{
160	double s;
161	volatile double t;
162	const double one = 1.0;
163
164#if !defined(__vax__)&&!defined(tahoe)
165	if (x != x)				/* NaN */
166		return (x);
167#endif	/* !defined(__vax__)&&!defined(tahoe) */
168	if (copysign(x,one) >= L)		/* already an integer */
169	    return (x);
170	s = copysign(L,x);
171	t = x + s;				/* x+s rounded to integer */
172	return (t - s);
173}
174
175long long
176llrint(double x)
177{
178	double s;
179	volatile double t;
180	const double one = 1.0;
181
182#if !defined(__vax__)&&!defined(tahoe)
183	if (x != x)				/* NaN */
184		return (x);
185#endif	/* !defined(__vax__)&&!defined(tahoe) */
186	if (copysign(x,one) >= L)		/* already an integer */
187	    return (x);
188	s = copysign(L,x);
189	t = x + s;				/* x+s rounded to integer */
190	return (t - s);
191}
192
193long
194lrintf(float x)
195{
196	float s;
197	volatile float t;
198	const float one = 1.0;
199
200#if !defined(__vax__)&&!defined(tahoe)
201	if (x != x)				/* NaN */
202		return (x);
203#endif	/* !defined(__vax__)&&!defined(tahoe) */
204	if (copysign(x,one) >= L)		/* already an integer */
205	    return (x);
206	s = copysign(L,x);
207	t = x + s;				/* x+s rounded to integer */
208	return (t - s);
209}
210
211long long
212llrintf(float x)
213{
214	float s;
215	volatile float t;
216	const float one = 1.0;
217
218#if !defined(__vax__)&&!defined(tahoe)
219	if (x != x)				/* NaN */
220		return (x);
221#endif	/* !defined(__vax__)&&!defined(tahoe) */
222	if (copysign(x,one) >= L)		/* already an integer */
223	    return (x);
224	s = copysign(L,x);
225	t = x + s;				/* x+s rounded to integer */
226	return (t - s);
227}
228
229double
230trunc(double x)
231{
232	return x < 0 ? ceil(x) : floor(x);
233}
234
235float
236truncf(float x)
237{
238	return x < 0 ? ceilf(x) : floorf(x);
239}
240