11.1Smatt/*	$NetBSD: floatdidf_ieee754.c,v 1.1 2013/08/24 00:51:48 matt Exp $	*/
21.1Smatt
31.1Smatt/*-
41.1Smatt * Copyright (c) 2013 The NetBSD Foundation, Inc.
51.1Smatt * All rights reserved.
61.1Smatt *
71.1Smatt * This code is derived from software contributed to The NetBSD Foundation
81.1Smatt * by Matt Thomas of 3am Software Foundry.
91.1Smatt *
101.1Smatt * Redistribution and use in source and binary forms, with or without
111.1Smatt * modification, are permitted provided that the following conditions
121.1Smatt * are met:
131.1Smatt * 1. Redistributions of source code must retain the above copyright
141.1Smatt *    notice, this list of conditions and the following disclaimer.
151.1Smatt * 2. Redistributions in binary form must reproduce the above copyright
161.1Smatt *    notice, this list of conditions and the following disclaimer in the
171.1Smatt *    documentation and/or other materials provided with the distribution.
181.1Smatt *
191.1Smatt * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
201.1Smatt * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
211.1Smatt * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
221.1Smatt * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
231.1Smatt * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
241.1Smatt * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
251.1Smatt * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
261.1Smatt * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
271.1Smatt * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
281.1Smatt * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
291.1Smatt * POSSIBILITY OF SUCH DAMAGE.
301.1Smatt */
311.1Smatt
321.1Smatt#include <sys/cdefs.h>
331.1Smatt#if defined(LIBC_SCCS) && !defined(lint)
341.1Smatt__RCSID("$NetBSD: floatdidf_ieee754.c,v 1.1 2013/08/24 00:51:48 matt Exp $");
351.1Smatt#endif /* LIBC_SCCS and not lint */
361.1Smatt
371.1Smatt#if defined(SOFTFLOAT) || defined(__ARM_EABI__)
381.1Smatt#include "softfloat/softfloat-for-gcc.h"
391.1Smatt#endif
401.1Smatt
411.1Smatt#include <limits.h>
421.1Smatt#include <machine/ieee.h>
431.1Smatt#include "quad.h"
441.1Smatt
451.1Smattdouble __floatdidf(quad_t);
461.1Smatt
471.1Smatt/*
481.1Smatt * Convert signed quad to double.
491.1Smatt */
501.1Smattdouble
511.1Smatt__floatdidf(quad_t x)
521.1Smatt{
531.1Smatt	union ieee_double_u ux = { .dblu_d = 0.0 };
541.1Smatt
551.1Smatt	if (x == 0)
561.1Smatt		return 0.0;
571.1Smatt	if (x == 1)
581.1Smatt		return 1.0;
591.1Smatt
601.1Smatt	if (x < 0) {
611.1Smatt		if (x == QUAD_MIN)
621.1Smatt			return -0x1.0p63;
631.1Smatt		ux.dblu_sign = 1;
641.1Smatt		x = -x;
651.1Smatt	}
661.1Smatt	u_int l = __builtin_clzll(x);
671.1Smatt	x <<= (l + 1);	/* clear implicit bit */
681.1Smatt	x >>= 64 - (DBL_FRACHBITS + DBL_FRACLBITS);
691.1Smatt	union uu u = { .uq = x };
701.1Smatt	ux.dblu_frach = u.ul[H];
711.1Smatt	ux.dblu_fracl = u.ul[L];
721.1Smatt	ux.dblu_exp = DBL_EXP_BIAS + 63 - l;
731.1Smatt
741.1Smatt	return ux.dblu_d;
751.1Smatt}
76