1 /* $OpenBSD: fixunsdfdi.c,v 1.7 2005/08/08 08:05:35 espie Exp $ */ 2 /*- 3 * Copyright (c) 1992, 1993 4 * The Regents of the University of California. All rights reserved. 5 * 6 * This software was developed by the Computer Systems Engineering group 7 * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and 8 * contributed to Berkeley. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 */ 34 35 #include "quad.h" 36 37 #define ONE_FOURTH ((int)1 << (INT_BITS - 2)) 38 #define ONE_HALF (ONE_FOURTH * 2.0) 39 #define ONE (ONE_FOURTH * 4.0) 40 41 /* 42 * Convert double to (unsigned) quad. 43 * Not sure what to do with negative numbers---for now, anything out 44 * of range becomes UQUAD_MAX. 45 */ 46 u_quad_t 47 __fixunsdfdi(double x) 48 { 49 union uu t; 50 unsigned int tmp; 51 52 if (x < 0) 53 return (UQUAD_MAX); /* ??? should be 0? ERANGE??? */ 54 #ifdef notdef /* this falls afoul of a GCC bug */ 55 if (x >= UQUAD_MAX) 56 return (UQUAD_MAX); 57 #else /* so we wire in 2^64-1 instead */ 58 if (x >= 18446744073709551615.0) /* XXX */ 59 return (UQUAD_MAX); 60 #endif 61 /* 62 * Now we know that 0 <= x <= 18446744073709549568. The upper 63 * limit is one ulp less than 18446744073709551615 tested for above. 64 * Dividing this by 2^32 will *not* round irrespective of any 65 * rounding modes (except if the result is an IEEE denorm). 66 * Furthermore, the quotient will fit into a 32-bit integer. 67 */ 68 tmp = x / ONE; 69 t.ul[L] = (unsigned int) (x - tmp * ONE); 70 t.ul[H] = tmp; 71 return (t.uq); 72 } 73