fixunsdfdi.c revision 1.5
11.5Skristerw/* $NetBSD: fixunsdfdi.c,v 1.5 1999/03/26 21:04:24 kristerw Exp $ */ 21.3Scgd 31.1Smycroft/*- 41.1Smycroft * Copyright (c) 1992, 1993 51.1Smycroft * The Regents of the University of California. All rights reserved. 61.1Smycroft * 71.1Smycroft * This software was developed by the Computer Systems Engineering group 81.1Smycroft * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and 91.1Smycroft * contributed to Berkeley. 101.1Smycroft * 111.1Smycroft * Redistribution and use in source and binary forms, with or without 121.1Smycroft * modification, are permitted provided that the following conditions 131.1Smycroft * are met: 141.1Smycroft * 1. Redistributions of source code must retain the above copyright 151.1Smycroft * notice, this list of conditions and the following disclaimer. 161.1Smycroft * 2. Redistributions in binary form must reproduce the above copyright 171.1Smycroft * notice, this list of conditions and the following disclaimer in the 181.1Smycroft * documentation and/or other materials provided with the distribution. 191.1Smycroft * 3. All advertising materials mentioning features or use of this software 201.1Smycroft * must display the following acknowledgement: 211.1Smycroft * This product includes software developed by the University of 221.1Smycroft * California, Berkeley and its contributors. 231.1Smycroft * 4. Neither the name of the University nor the names of its contributors 241.1Smycroft * may be used to endorse or promote products derived from this software 251.1Smycroft * without specific prior written permission. 261.1Smycroft * 271.1Smycroft * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 281.1Smycroft * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 291.1Smycroft * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 301.1Smycroft * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 311.1Smycroft * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 321.1Smycroft * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 331.1Smycroft * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 341.1Smycroft * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 351.1Smycroft * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 361.1Smycroft * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 371.1Smycroft * SUCH DAMAGE. 381.1Smycroft */ 391.1Smycroft 401.4Schristos#include <sys/cdefs.h> 411.1Smycroft#if defined(LIBC_SCCS) && !defined(lint) 421.3Scgd#if 0 431.3Scgdstatic char sccsid[] = "@(#)fixunsdfdi.c 8.1 (Berkeley) 6/4/93"; 441.3Scgd#else 451.5Skristerw__RCSID("$NetBSD: fixunsdfdi.c,v 1.5 1999/03/26 21:04:24 kristerw Exp $"); 461.3Scgd#endif 471.1Smycroft#endif /* LIBC_SCCS and not lint */ 481.1Smycroft 491.1Smycroft#include "quad.h" 501.1Smycroft 511.2Scgd#define ONE_FOURTH ((long)1 << (LONG_BITS - 2)) 521.1Smycroft#define ONE_HALF (ONE_FOURTH * 2.0) 531.1Smycroft#define ONE (ONE_FOURTH * 4.0) 541.1Smycroft 551.1Smycroft/* 561.1Smycroft * Convert double to (unsigned) quad. 571.1Smycroft * Not sure what to do with negative numbers---for now, anything out 581.1Smycroft * of range becomes UQUAD_MAX. 591.1Smycroft */ 601.1Smycroftu_quad_t 611.1Smycroft__fixunsdfdi(x) 621.1Smycroft double x; 631.1Smycroft{ 641.1Smycroft union uu t; 651.5Skristerw unsigned long tmp; 661.1Smycroft 671.1Smycroft if (x < 0) 681.1Smycroft return (UQUAD_MAX); /* ??? should be 0? ERANGE??? */ 691.1Smycroft#ifdef notdef /* this falls afoul of a GCC bug */ 701.1Smycroft if (x >= UQUAD_MAX) 711.1Smycroft return (UQUAD_MAX); 721.1Smycroft#else /* so we wire in 2^64-1 instead */ 731.1Smycroft if (x >= 18446744073709551615.0) /* XXX */ 741.1Smycroft return (UQUAD_MAX); 751.1Smycroft#endif 761.1Smycroft /* 771.5Skristerw * Now we know that 0 <= x <= 18446744073709549568. The upper 781.5Skristerw * limit is one ulp less than 18446744073709551615 tested for above. 791.5Skristerw * Dividing this by 2^32 will *not* round irrespective of any 801.5Skristerw * rounding modes (except if the result is an IEEE denorm). 811.5Skristerw * Furthermore, the quotient will fit into a 32-bit integer. 821.1Smycroft */ 831.5Skristerw tmp = x / ONE; 841.5Skristerw t.ul[L] = (unsigned long) (x - tmp * ONE); 851.5Skristerw t.ul[H] = tmp; 861.1Smycroft return (t.uq); 871.1Smycroft} 88