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