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File: [cvs.NetBSD.org] / src / lib / libc / quad / floatundisf_ieee754.c (download)

Revision 1.2, Sat Aug 24 00:51:48 2013 UTC (7 years, 1 month ago) by matt
Branch: MAIN
CVS Tags: yamt-pagecache-base9, tls-maxphys-base, tls-earlyentropy-base, tls-earlyentropy, riastradh-xf86-video-intel-2-7-1-pre-2-21-15, riastradh-drm2-base3, prg-localcount2-base3, prg-localcount2-base2, prg-localcount2-base1, prg-localcount2-base, prg-localcount2, phil-wifi-base, phil-wifi-20200421, phil-wifi-20200411, phil-wifi-20200406, phil-wifi-20191119, phil-wifi-20190609, phil-wifi, pgoyette-localcount-base, pgoyette-localcount-20170426, pgoyette-localcount-20170320, pgoyette-localcount-20170107, pgoyette-localcount-20161104, pgoyette-localcount-20160806, pgoyette-localcount-20160726, pgoyette-localcount, pgoyette-compat-merge-20190127, pgoyette-compat-base, pgoyette-compat-20190127, pgoyette-compat-20190118, pgoyette-compat-1226, pgoyette-compat-1126, pgoyette-compat-1020, pgoyette-compat-0930, pgoyette-compat-0906, pgoyette-compat-0728, pgoyette-compat-0625, pgoyette-compat-0521, pgoyette-compat-0502, pgoyette-compat-0422, pgoyette-compat-0415, pgoyette-compat-0407, pgoyette-compat-0330, pgoyette-compat-0322, pgoyette-compat-0315, pgoyette-compat, perseant-stdc-iso10646-base, perseant-stdc-iso10646, netbsd-9-base, netbsd-9-0-RELEASE, netbsd-9-0-RC2, netbsd-9-0-RC1, netbsd-9, netbsd-8-base, netbsd-8-2-RELEASE, netbsd-8-1-RELEASE, netbsd-8-1-RC1, netbsd-8-0-RELEASE, netbsd-8-0-RC2, netbsd-8-0-RC1, netbsd-8, netbsd-7-nhusb-base-20170116, netbsd-7-nhusb-base, netbsd-7-nhusb, netbsd-7-base, netbsd-7-2-RELEASE, netbsd-7-1-RELEASE, netbsd-7-1-RC2, netbsd-7-1-RC1, netbsd-7-1-2-RELEASE, netbsd-7-1-1-RELEASE, netbsd-7-1, netbsd-7-0-RELEASE, netbsd-7-0-RC3, netbsd-7-0-RC2, netbsd-7-0-RC1, netbsd-7-0-2-RELEASE, netbsd-7-0-1-RELEASE, netbsd-7-0, netbsd-7, matt-nb8-mediatek-base, matt-nb8-mediatek, localcount-20160914, is-mlppp-base, is-mlppp, bouyer-socketcan-base1, bouyer-socketcan-base, bouyer-socketcan, HEAD
Branch point for: yamt-pagecache, tls-maxphys
Changes since 1.1: +5 -4 lines

Add IEEE 754 versions of
	fixdfdi.c fixsfdi.c fixunsdfdi.c fixunssfdi.c
	floatdidf.c floatdisf.c floatundidf.c floatundisf.c
These don't FP so are well suited to softfloat implementation.

/*	$NetBSD: floatundisf_ieee754.c,v 1.2 2013/08/24 00:51:48 matt Exp $	*/

/*-
 * Copyright (c) 2013 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Matt Thomas of 3am Software Foundry.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include <sys/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
__RCSID("$NetBSD: floatundisf_ieee754.c,v 1.2 2013/08/24 00:51:48 matt Exp $");
#endif /* LIBC_SCCS and not lint */

#if defined(SOFTFLOAT) || defined(__ARM_EABI__)
#include "softfloat/softfloat-for-gcc.h"
#endif

#include <machine/ieee.h>
#include "quad.h"

float __floatundisf(u_quad_t);

/*
 * Convert unsigned quad to float.
 */
float
__floatundisf(u_quad_t x)
{
	union ieee_single_u ux = { .sngu_f = 0.0 };

	if (x == 0)
		return 0.0;
	if (x == 1)
		return 1.0;

#if defined(_LP64) || defined(__mips_n32)
	u_int l = __builtin_clzll(x);
	x <<= (l + 1);	/* clear implicit bit */

	ux.sngu_frac = x >> (64 - SNG_FRACBITS);
#else
	union uu u = { .uq = x };
	uint32_t frac;
	u_int l;
	if (u.ul[H] == 0) {
		l = __builtin_clz(u.ul[L]);
		frac = u.ul[L] << (l + 1);	/* clear implicit bit */
		l += 32;
	} else {
		l = __builtin_clz(u.ul[H]);
		frac = u.ul[H] << (l + 1);	/* clear implicit bit */
		frac |= u.ul[L] >> (32 - (l + 1));
	}

	ux.sngu_frac = frac >> (32 - SNG_FRACBITS);
#endif
	ux.sngu_exp = SNG_EXP_BIAS + 63 - l;

	return ux.sngu_f;
}