1 /* $NetBSD: fixunsdfdi.c,v 1.3 1995/02/27 17:29:58 cgd Exp $ */ 2 3 /*- 4 * Copyright (c) 1992, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This software was developed by the Computer Systems Engineering group 8 * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and 9 * contributed to Berkeley. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 3. All advertising materials mentioning features or use of this software 20 * must display the following acknowledgement: 21 * This product includes software developed by the University of 22 * California, Berkeley and its contributors. 23 * 4. Neither the name of the University nor the names of its contributors 24 * may be used to endorse or promote products derived from this software 25 * without specific prior written permission. 26 * 27 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 28 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 29 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 30 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 31 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 32 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 33 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 34 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 35 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 36 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 37 * SUCH DAMAGE. 38 */ 39 40 #if defined(LIBC_SCCS) && !defined(lint) 41 #if 0 42 static char sccsid[] = "@(#)fixunsdfdi.c 8.1 (Berkeley) 6/4/93"; 43 #else 44 static char rcsid[] = "$NetBSD: fixunsdfdi.c,v 1.3 1995/02/27 17:29:58 cgd Exp $"; 45 #endif 46 #endif /* LIBC_SCCS and not lint */ 47 48 #include "quad.h" 49 50 #define ONE_FOURTH ((long)1 << (LONG_BITS - 2)) 51 #define ONE_HALF (ONE_FOURTH * 2.0) 52 #define ONE (ONE_FOURTH * 4.0) 53 54 /* 55 * Convert double to (unsigned) quad. 56 * Not sure what to do with negative numbers---for now, anything out 57 * of range becomes UQUAD_MAX. 58 */ 59 u_quad_t 60 __fixunsdfdi(x) 61 double x; 62 { 63 double toppart; 64 union uu t; 65 66 if (x < 0) 67 return (UQUAD_MAX); /* ??? should be 0? ERANGE??? */ 68 #ifdef notdef /* this falls afoul of a GCC bug */ 69 if (x >= UQUAD_MAX) 70 return (UQUAD_MAX); 71 #else /* so we wire in 2^64-1 instead */ 72 if (x >= 18446744073709551615.0) /* XXX */ 73 return (UQUAD_MAX); 74 #endif 75 /* 76 * Get the upper part of the result. Note that the divide 77 * may round up; we want to avoid this if possible, so we 78 * subtract `1/2' first. 79 */ 80 toppart = (x - ONE_HALF) / ONE; 81 /* 82 * Now build a u_quad_t out of the top part. The difference 83 * between x and this is the bottom part (this may introduce 84 * a few fuzzy bits, but what the heck). With any luck this 85 * difference will be nonnegative: x should wind up in the 86 * range [0..ULONG_MAX]. For paranoia, we assume [LONG_MIN.. 87 * 2*ULONG_MAX] instead. 88 */ 89 t.ul[H] = (unsigned long)toppart; 90 t.ul[L] = 0; 91 x -= (double)t.uq; 92 if (x < 0) { 93 t.ul[H]--; 94 x += ULONG_MAX; 95 } 96 if (x > ULONG_MAX) { 97 t.ul[H]++; 98 x -= ULONG_MAX; 99 } 100 t.ul[L] = (u_long)x; 101 return (t.uq); 102 } 103