1 /* $NetBSD: floatdidf_ieee754.c,v 1.1 2013/08/24 00:51:48 matt Exp $ */ 2 3 /*- 4 * Copyright (c) 2013 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Matt Thomas of 3am Software Foundry. 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 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 #include <sys/cdefs.h> 33 #if defined(LIBC_SCCS) && !defined(lint) 34 __RCSID("$NetBSD: floatdidf_ieee754.c,v 1.1 2013/08/24 00:51:48 matt Exp $"); 35 #endif /* LIBC_SCCS and not lint */ 36 37 #if defined(SOFTFLOAT) || defined(__ARM_EABI__) 38 #include "softfloat/softfloat-for-gcc.h" 39 #endif 40 41 #include <limits.h> 42 #include <machine/ieee.h> 43 #include "quad.h" 44 45 double __floatdidf(quad_t); 46 47 /* 48 * Convert signed quad to double. 49 */ 50 double 51 __floatdidf(quad_t x) 52 { 53 union ieee_double_u ux = { .dblu_d = 0.0 }; 54 55 if (x == 0) 56 return 0.0; 57 if (x == 1) 58 return 1.0; 59 60 if (x < 0) { 61 if (x == QUAD_MIN) 62 return -0x1.0p63; 63 ux.dblu_sign = 1; 64 x = -x; 65 } 66 u_int l = __builtin_clzll(x); 67 x <<= (l + 1); /* clear implicit bit */ 68 x >>= 64 - (DBL_FRACHBITS + DBL_FRACLBITS); 69 union uu u = { .uq = x }; 70 ux.dblu_frach = u.ul[H]; 71 ux.dblu_fracl = u.ul[L]; 72 ux.dblu_exp = DBL_EXP_BIAS + 63 - l; 73 74 return ux.dblu_d; 75 } 76