1 /* $NetBSD: n_floor.c,v 1.8 2014/03/16 09:51:39 martin 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 48 #ifdef __weak_alias 49 __weak_alias(ceill, ceil); 50 __weak_alias(floorl, floor); 51 __weak_alias(truncl, trunc); 52 #endif 53 54 /* 55 * floor(x) := the largest integer no larger than x; 56 * ceil(x) := -floor(-x), for all real x. 57 * 58 * Note: Inexact will be signaled if x is not an integer, as is 59 * customary for IEEE 754. No other signal can be emitted. 60 */ 61 double 62 floor(double x) 63 { 64 volatile double y; 65 66 if ( 67 #if !defined(__vax__)&&!defined(tahoe) 68 x != x || /* NaN */ 69 #endif /* !defined(__vax__)&&!defined(tahoe) */ 70 x >= L) /* already an even integer */ 71 return x; 72 else if (x < (double)0) 73 return -ceil(-x); 74 else { /* now 0 <= x < L */ 75 y = L+x; /* destructive store must be forced */ 76 y -= L; /* an integer, and |x-y| < 1 */ 77 return x < y ? y-(double)1 : y; 78 } 79 } 80 81 float 82 floorf(float x) 83 { 84 return floor((double)x); 85 } 86 87 double 88 ceil(double x) 89 { 90 volatile double y; 91 92 if ( 93 #if !defined(__vax__)&&!defined(tahoe) 94 x != x || /* NaN */ 95 #endif /* !defined(__vax__)&&!defined(tahoe) */ 96 x >= L) /* already an even integer */ 97 return x; 98 else if (x < (double)0) 99 return -floor(-x); 100 else { /* now 0 <= x < L */ 101 y = L+x; /* destructive store must be forced */ 102 y -= L; /* an integer, and |x-y| < 1 */ 103 return x > y ? y+(double)1 : y; 104 } 105 } 106 107 float 108 ceilf(float x) 109 { 110 return ceil((double)x); 111 } 112 113 #ifndef ns32000 /* rint() is in ./NATIONAL/support.s */ 114 /* 115 * algorithm for rint(x) in pseudo-pascal form ... 116 * 117 * real rint(x): real x; 118 * ... delivers integer nearest x in direction of prevailing rounding 119 * ... mode 120 * const L = (last consecutive integer)/2 121 * = 2**55; for VAX D 122 * = 2**52; for IEEE 754 Double 123 * real s,t; 124 * begin 125 * if x != x then return x; ... NaN 126 * if |x| >= L then return x; ... already an integer 127 * s := copysign(L,x); 128 * t := x + s; ... = (x+s) rounded to integer 129 * return t - s 130 * end; 131 * 132 * Note: Inexact will be signaled if x is not an integer, as is 133 * customary for IEEE 754. No other signal can be emitted. 134 */ 135 double 136 rint(double x) 137 { 138 double s; 139 volatile double t; 140 const double one = 1.0; 141 142 #if !defined(__vax__)&&!defined(tahoe) 143 if (x != x) /* NaN */ 144 return (x); 145 #endif /* !defined(__vax__)&&!defined(tahoe) */ 146 if (copysign(x,one) >= L) /* already an integer */ 147 return (x); 148 s = copysign(L,x); 149 t = x + s; /* x+s rounded to integer */ 150 return (t - s); 151 } 152 #endif /* not national */ 153 154 long 155 lrint(double x) 156 { 157 double s; 158 volatile double t; 159 const double one = 1.0; 160 161 #if !defined(__vax__)&&!defined(tahoe) 162 if (x != x) /* NaN */ 163 return (x); 164 #endif /* !defined(__vax__)&&!defined(tahoe) */ 165 if (copysign(x,one) >= L) /* already an integer */ 166 return (x); 167 s = copysign(L,x); 168 t = x + s; /* x+s rounded to integer */ 169 return (t - s); 170 } 171 172 long long 173 llrint(double x) 174 { 175 double s; 176 volatile double t; 177 const double one = 1.0; 178 179 #if !defined(__vax__)&&!defined(tahoe) 180 if (x != x) /* NaN */ 181 return (x); 182 #endif /* !defined(__vax__)&&!defined(tahoe) */ 183 if (copysign(x,one) >= L) /* already an integer */ 184 return (x); 185 s = copysign(L,x); 186 t = x + s; /* x+s rounded to integer */ 187 return (t - s); 188 } 189 190 long 191 lrintf(float x) 192 { 193 float s; 194 volatile float t; 195 const float one = 1.0; 196 197 #if !defined(__vax__)&&!defined(tahoe) 198 if (x != x) /* NaN */ 199 return (x); 200 #endif /* !defined(__vax__)&&!defined(tahoe) */ 201 if (copysign(x,one) >= L) /* already an integer */ 202 return (x); 203 s = copysign(L,x); 204 t = x + s; /* x+s rounded to integer */ 205 return (t - s); 206 } 207 208 long long 209 llrintf(float x) 210 { 211 float s; 212 volatile float t; 213 const float one = 1.0; 214 215 #if !defined(__vax__)&&!defined(tahoe) 216 if (x != x) /* NaN */ 217 return (x); 218 #endif /* !defined(__vax__)&&!defined(tahoe) */ 219 if (copysign(x,one) >= L) /* already an integer */ 220 return (x); 221 s = copysign(L,x); 222 t = x + s; /* x+s rounded to integer */ 223 return (t - s); 224 } 225 226 double 227 trunc(double x) 228 { 229 return x < 0 ? ceil(x) : floor(x); 230 } 231 232 float 233 truncf(float x) 234 { 235 return x < 0 ? ceilf(x) : floorf(x); 236 } 237