1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 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 "quad.h" 37 38 #define ONE_FOURTH (1L << (LONG_BITS - 2)) 39 #define ONE_HALF (ONE_FOURTH * 2.0) 40 #define ONE (ONE_FOURTH * 4.0) 41 42 /* 43 * Convert float to (unsigned) quad. We do most of our work in double, 44 * out of sheer paranoia. 45 * 46 * Not sure what to do with negative numbers---for now, anything out 47 * of range becomes UQUAD_MAX. 48 * 49 * N.B.: must use new ANSI syntax (sorry). 50 */ 51 u_quad_t 52 __fixunssfdi(float f) 53 { 54 double x, toppart; 55 union uu t; 56 57 if (f < 0) 58 return (UQUAD_MAX); /* ??? should be 0? ERANGE??? */ 59 #ifdef notdef /* this falls afoul of a GCC bug */ 60 if (f >= UQUAD_MAX) 61 return (UQUAD_MAX); 62 #else /* so we wire in 2^64-1 instead */ 63 if (f >= 18446744073709551615.0) 64 return (UQUAD_MAX); 65 #endif 66 x = f; 67 /* 68 * Get the upper part of the result. Note that the divide 69 * may round up; we want to avoid this if possible, so we 70 * subtract `1/2' first. 71 */ 72 toppart = (x - ONE_HALF) / ONE; 73 /* 74 * Now build a u_quad_t out of the top part. The difference 75 * between x and this is the bottom part (this may introduce 76 * a few fuzzy bits, but what the heck). With any luck this 77 * difference will be nonnegative: x should wind up in the 78 * range [0..ULONG_MAX]. For paranoia, we assume [LONG_MIN.. 79 * 2*ULONG_MAX] instead. 80 */ 81 t.ul[H] = (unsigned long)toppart; 82 t.ul[L] = 0; 83 x -= (double)t.uq; 84 if (x < 0) { 85 t.ul[H]--; 86 x += (double)ULONG_MAX; 87 } 88 if (x > (double)ULONG_MAX) { 89 t.ul[H]++; 90 x -= (double)ULONG_MAX; 91 } 92 t.ul[L] = (u_long)x; 93 return (t.uq); 94 } 95