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