1/* $NetBSD: floatdisf.c,v 1.9 2012/08/05 04:28:58 matt Exp $ */ 2 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 <sys/cdefs.h> 37#if defined(LIBC_SCCS) && !defined(lint) 38#if 0 39static char sccsid[] = "@(#)floatdisf.c 8.1 (Berkeley) 6/4/93"; 40#else 41__RCSID("$NetBSD: floatdisf.c,v 1.9 2012/08/05 04:28:58 matt Exp $"); 42#endif 43#endif /* LIBC_SCCS and not lint */ 44 45#if defined(SOFTFLOAT) || defined(__ARM_EABI__) 46#include "softfloat/softfloat-for-gcc.h" 47#endif 48 49#include "quad.h" 50 51/* 52 * Convert (signed) quad to float. 53 */ 54float 55__floatdisf(quad_t x) 56{ 57 float f; 58 union uu u; 59 int neg; 60 61 /* 62 * Get an unsigned number first, by negating if necessary. 63 */ 64 if (x < 0) 65 u.q = -x, neg = 1; 66 else 67 u.q = x, neg = 0; 68 69 /* 70 * Now u.ul[H] has the factor of 2^32 (or whatever) and u.ul[L] 71 * has the units. Ideally we could just set f, add INT_BITS to 72 * its exponent, and then add the units, but this is portable 73 * code and does not know how to get at an exponent. Machine- 74 * specific code may be able to do this more efficiently. 75 * 76 * Using double here may be excessive paranoia. 77 */ 78 f = (double)u.ul[H] * (((int)1 << (unsigned int)(INT_BITS - 2)) * 4.0); 79 f += u.ul[L]; 80 81 return (neg ? -f : f); 82} 83