1 /* $NetBSD: fixunssfdi.c,v 1.6 2003/08/07 16:43:16 agc 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. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 */ 35 36 #include <sys/cdefs.h> 37 #if defined(LIBC_SCCS) && !defined(lint) 38 #if 0 39 static char sccsid[] = "@(#)fixunssfdi.c 8.1 (Berkeley) 6/4/93"; 40 #else 41 __RCSID("$NetBSD: fixunssfdi.c,v 1.6 2003/08/07 16:43:16 agc Exp $"); 42 #endif 43 #endif /* LIBC_SCCS and not lint */ 44 45 #include "quad.h" 46 47 #define ONE_FOURTH ((int)1 << (INT_BITS - 2)) 48 #define ONE_HALF (ONE_FOURTH * 2.0) 49 #define ONE (ONE_FOURTH * 4.0) 50 51 /* 52 * Convert float to (unsigned) quad. We do most of our work in double, 53 * out of sheer paranoia. 54 * 55 * Not sure what to do with negative numbers---for now, anything out 56 * of range becomes UQUAD_MAX. 57 * 58 * N.B.: must use new ANSI syntax (sorry). 59 */ 60 u_quad_t 61 __fixunssfdi(float f) 62 { 63 double x, toppart; 64 union uu t; 65 66 if (f < 0) 67 return (UQUAD_MAX); /* ??? should be 0? ERANGE??? */ 68 #ifdef notdef /* this falls afoul of a GCC bug */ 69 if (f >= UQUAD_MAX) 70 return (UQUAD_MAX); 71 #else /* so we wire in 2^64-1 instead */ 72 if (f >= 18446744073709551615.0) /* XXX */ 73 return (UQUAD_MAX); 74 #endif 75 x = f; 76 /* 77 * Get the upper part of the result. Note that the divide 78 * may round up; we want to avoid this if possible, so we 79 * subtract `1/2' first. 80 */ 81 toppart = (x - ONE_HALF) / ONE; 82 /* 83 * Now build a u_quad_t out of the top part. The difference 84 * between x and this is the bottom part (this may introduce 85 * a few fuzzy bits, but what the heck). With any luck this 86 * difference will be nonnegative: x should wind up in the 87 * range [0..UINT_MAX]. For paranoia, we assume [INT_MIN.. 88 * 2*UINT_MAX] instead. 89 */ 90 t.ul[H] = (unsigned int)toppart; 91 t.ul[L] = 0; 92 x -= (double)t.uq; 93 if (x < 0) { 94 t.ul[H]--; 95 x += UINT_MAX; 96 } 97 if (x > UINT_MAX) { 98 t.ul[H]++; 99 x -= UINT_MAX; 100 } 101 t.ul[L] = (u_int)x; 102 return (t.uq); 103 } 104