11.2Smatt/*	$NetBSD: floatundisf_ieee754.c,v 1.2 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)
341.2Smatt__RCSID("$NetBSD: floatundisf_ieee754.c,v 1.2 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 <machine/ieee.h>
421.1Smatt#include "quad.h"
431.1Smatt
441.1Smattfloat __floatundisf(u_quad_t);
451.1Smatt
461.1Smatt/*
471.1Smatt * Convert unsigned quad to float.
481.1Smatt */
491.1Smattfloat
501.1Smatt__floatundisf(u_quad_t x)
511.1Smatt{
521.1Smatt	union ieee_single_u ux = { .sngu_f = 0.0 };
531.1Smatt
541.1Smatt	if (x == 0)
551.1Smatt		return 0.0;
561.1Smatt	if (x == 1)
571.1Smatt		return 1.0;
581.1Smatt
591.1Smatt#if defined(_LP64) || defined(__mips_n32)
601.1Smatt	u_int l = __builtin_clzll(x);
611.1Smatt	x <<= (l + 1);	/* clear implicit bit */
621.1Smatt
631.1Smatt	ux.sngu_frac = x >> (64 - SNG_FRACBITS);
641.1Smatt#else
651.1Smatt	union uu u = { .uq = x };
661.1Smatt	uint32_t frac;
671.2Smatt	u_int l;
681.1Smatt	if (u.ul[H] == 0) {
691.2Smatt		l = __builtin_clz(u.ul[L]);
701.1Smatt		frac = u.ul[L] << (l + 1);	/* clear implicit bit */
711.1Smatt		l += 32;
721.1Smatt	} else {
731.2Smatt		l = __builtin_clz(u.ul[H]);
741.1Smatt		frac = u.ul[H] << (l + 1);	/* clear implicit bit */
751.1Smatt		frac |= u.ul[L] >> (32 - (l + 1));
761.1Smatt	}
771.1Smatt
781.1Smatt	ux.sngu_frac = frac >> (32 - SNG_FRACBITS);
791.1Smatt#endif
801.1Smatt	ux.sngu_exp = SNG_EXP_BIAS + 63 - l;
811.1Smatt
821.1Smatt	return ux.sngu_f;
831.1Smatt}
84