1 /* $NetBSD: floatunditf_ieee754.c,v 1.3 2012/03/25 19:53:18 christos 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 39 static char sccsid[] = "@(#)floatunsdidf.c 8.1 (Berkeley) 6/4/93"; 40 #else 41 __RCSID("$NetBSD: floatunditf_ieee754.c,v 1.3 2012/03/25 19:53:18 christos Exp $"); 42 #endif 43 #endif /* LIBC_SCCS and not lint */ 44 45 #include "quad.h" 46 #ifdef __vax__ 47 #error vax does not support a distinct long double 48 #endif 49 #include <machine/ieee.h> 50 51 /* 52 * Convert (unsigned) quad to long double. 53 * This is exactly like floatdidf.c except that negatives never occur. 54 */ 55 long double 56 __floatunditf(u_quad_t x) 57 { 58 #if 0 59 long double ld; 60 union uu u; 61 62 u.uq = x; 63 ld = (long double)u.ul[H] * (((int)1 << (INT_BITS - 2)) * 4.0); 64 ld += u.ul[L]; 65 return (ld); 66 #else 67 union ieee_ext_u extu; 68 quad_t tmp = x; /* must be signed */ 69 unsigned int width = 64; 70 unsigned int bit = 0; 71 quad_t mask = ~(quad_t)0; 72 73 if (x == 0) 74 return 0.0L; 75 if (x == 1) 76 return 1.0L; 77 78 while (mask != 0 && (tmp >= 0)) { 79 width >>= 1; 80 mask <<= width; 81 if ((tmp & mask) == 0) { 82 tmp <<= width; 83 bit += width; 84 } 85 } 86 87 x <<= (bit + 1); 88 extu.extu_sign = 0; 89 extu.extu_exp = EXT_EXP_BIAS + (64 - (bit + 1)); 90 extu.extu_frach = (unsigned int)(x >> (64 - EXT_FRACHBITS)); 91 x <<= EXT_FRACHBITS; 92 #ifdef EXT_FRACHMBITS 93 extu.extu_frachm =(unsigned int)(x >> (64 - EXT_FRACHMBITS)); 94 x <<= EXT_FRACHMBITS; 95 #endif 96 #ifdef EXT_FRACLMBITS 97 extu.extu_fraclm =(unsigned int)(x >> (64 - EXT_FRACLMBITS)); 98 x <<= EXT_FRACLMBITS; 99 #endif 100 extu.extu_fracl =(unsigned int)(x >> (64 - EXT_FRACLBITS)); 101 102 return extu.extu_ld; 103 #endif 104 } 105