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
33 static 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
40 vc(L, 4503599627370496.0E0 ,0000,5c00,0000,0000, 55, 1.0) /* 2**55 */
41
42 ic(L, 4503599627370496.0E0, 52, 1.0) /* 2**52 */
43
44 #ifdef vccast
45 #define L vccast(L)
46 #endif
47
__weak_alias(ceill,ceil)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 */
60 double
61 floor(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
80 float
floorf(float x)81 floorf(float x)
82 {
83 return floor((double)x);
84 }
85
86 double
ceil(double x)87 ceil(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
106 float
ceilf(float x)107 ceilf(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 */
133 double
rint(double x)134 rint(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
151 float
rintf(float x)152 rintf(float x)
153 {
154 return rint((double)x);
155 }
156
157 long
lrint(double x)158 lrint(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
175 long long
llrint(double x)176 llrint(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
193 long
lrintf(float x)194 lrintf(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
211 long long
llrintf(float x)212 llrintf(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
229 double
trunc(double x)230 trunc(double x)
231 {
232 return x < 0 ? ceil(x) : floor(x);
233 }
234
235 float
truncf(float x)236 truncf(float x)
237 {
238 return x < 0 ? ceilf(x) : floorf(x);
239 }
240