1 /* $OpenBSD: s_lrint.c,v 1.7 2011/07/06 00:02:42 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 /* LINTLIBRARY */ 31 32 #include <sys/types.h> 33 #include <sys/limits.h> 34 #include <float.h> 35 #include <math.h> 36 #include <ieeefp.h> 37 #include <machine/ieee.h> 38 39 #include "math_private.h" 40 41 #ifndef LRINTNAME 42 #define LRINTNAME lrint 43 #define RESTYPE long int 44 #define RESTYPE_MIN LONG_MIN 45 #define RESTYPE_MAX LONG_MAX 46 #endif 47 48 #define RESTYPE_BITS (sizeof(RESTYPE) * 8) 49 50 static const double 51 TWO52[2]={ 52 4.50359962737049600000e+15, /* 0x43300000, 0x00000000 */ 53 -4.50359962737049600000e+15, /* 0xC3300000, 0x00000000 */ 54 }; 55 56 RESTYPE 57 LRINTNAME(double x) 58 { 59 u_int32_t i0, i1; 60 int e, s, shift; 61 RESTYPE res; 62 63 GET_HIGH_WORD(i0, x); 64 e = i0 >> DBL_FRACHBITS; 65 s = e >> DBL_EXPBITS; 66 e = (e & 0x7ff) - DBL_EXP_BIAS; 67 68 /* 1.0 x 2^31 (or 2^63) is already too large */ 69 if (e >= (int)RESTYPE_BITS - 1) 70 return (s ? RESTYPE_MIN : RESTYPE_MAX); /* ??? unspecified */ 71 72 /* >= 2^52 is already an exact integer */ 73 if (e < DBL_FRACBITS) { 74 volatile double t = x; /* clip extra precision */ 75 /* round, using current direction */ 76 t += TWO52[s]; 77 t -= TWO52[s]; 78 x = t; 79 } 80 81 EXTRACT_WORDS(i0, i1, x); 82 e = ((i0 >> DBL_FRACHBITS) & 0x7ff) - DBL_EXP_BIAS; 83 i0 &= 0xfffff; 84 i0 |= (1 << DBL_FRACHBITS); 85 86 if (e < 0) 87 return (0); 88 89 shift = e - DBL_FRACBITS; 90 if (shift >=0) 91 res = (shift < RESTYPE_BITS ? (RESTYPE)i1 << shift : 0); 92 else 93 res = (shift > -RESTYPE_BITS ? (RESTYPE)i1 >> -shift : 0); 94 shift += 32; 95 if (shift >=0) 96 res |= (shift < RESTYPE_BITS ? (RESTYPE)i0 << shift : 0); 97 else 98 res |= (shift > -RESTYPE_BITS ? (RESTYPE)i0 >> -shift : 0); 99 100 return (s ? -res : res); 101 } 102 103 #if LDBL_MANT_DIG == 53 104 #ifdef lint 105 /* PROTOLIB1 */ 106 long int lrintl(long double); 107 #else /* lint */ 108 __weak_alias(lrintl, lrint); 109 #endif /* lint */ 110 #endif /* LDBL_MANT_DIG == 53 */ 111