1 /* $OpenBSD: s_lrint.c,v 1.8 2013/01/13 03:45:00 martynas Exp $ */ 2 /* $NetBSD: lrint.c,v 1.3 2004/10/13 15:18:32 drochner Exp $ */ 3 4 /*- 5 * Copyright (c) 2004 6 * Matthias Drochner. All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 */ 29 30 #include <sys/types.h> 31 #include <sys/limits.h> 32 #include <float.h> 33 #include <math.h> 34 #include <ieeefp.h> 35 #include <machine/ieee.h> 36 37 #include "math_private.h" 38 39 #ifndef LRINTNAME 40 #define LRINTNAME lrint 41 #define RESTYPE long int 42 #define RESTYPE_MIN LONG_MIN 43 #define RESTYPE_MAX LONG_MAX 44 #endif 45 46 #define RESTYPE_BITS (sizeof(RESTYPE) * 8) 47 48 static const double 49 TWO52[2]={ 50 4.50359962737049600000e+15, /* 0x43300000, 0x00000000 */ 51 -4.50359962737049600000e+15, /* 0xC3300000, 0x00000000 */ 52 }; 53 54 RESTYPE 55 LRINTNAME(double x) 56 { 57 u_int32_t i0, i1; 58 int e, s, shift; 59 RESTYPE res; 60 61 GET_HIGH_WORD(i0, x); 62 e = i0 >> DBL_FRACHBITS; 63 s = e >> DBL_EXPBITS; 64 e = (e & 0x7ff) - DBL_EXP_BIAS; 65 66 /* 1.0 x 2^31 (or 2^63) is already too large */ 67 if (e >= (int)RESTYPE_BITS - 1) 68 return (s ? RESTYPE_MIN : RESTYPE_MAX); /* ??? unspecified */ 69 70 /* >= 2^52 is already an exact integer */ 71 if (e < DBL_FRACBITS) { 72 volatile double t = x; /* clip extra precision */ 73 /* round, using current direction */ 74 t += TWO52[s]; 75 t -= TWO52[s]; 76 x = t; 77 } 78 79 EXTRACT_WORDS(i0, i1, x); 80 e = ((i0 >> DBL_FRACHBITS) & 0x7ff) - DBL_EXP_BIAS; 81 i0 &= 0xfffff; 82 i0 |= (1 << DBL_FRACHBITS); 83 84 if (e < 0) 85 return (0); 86 87 shift = e - DBL_FRACBITS; 88 if (shift >=0) 89 res = (shift < RESTYPE_BITS ? (RESTYPE)i1 << shift : 0); 90 else 91 res = (shift > -RESTYPE_BITS ? (RESTYPE)i1 >> -shift : 0); 92 shift += 32; 93 if (shift >=0) 94 res |= (shift < RESTYPE_BITS ? (RESTYPE)i0 << shift : 0); 95 else 96 res |= (shift > -RESTYPE_BITS ? (RESTYPE)i0 >> -shift : 0); 97 98 return (s ? -res : res); 99 } 100 101 #if LDBL_MANT_DIG == 53 102 __weak_alias(lrintl, lrint); 103 #endif /* LDBL_MANT_DIG == 53 */ 104