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floatdisf_ieee754.c revision 1.2.4.2 
      1  1.2.4.2  yamt /*	$NetBSD: floatdisf_ieee754.c,v 1.2.4.2 2014/05/22 11:36:53 yamt Exp $	*/
      2  1.2.4.2  yamt 
      3  1.2.4.2  yamt /*-
      4  1.2.4.2  yamt  * Copyright (c) 2013 The NetBSD Foundation, Inc.
      5  1.2.4.2  yamt  * All rights reserved.
      6  1.2.4.2  yamt  *
      7  1.2.4.2  yamt  * This code is derived from software contributed to The NetBSD Foundation
      8  1.2.4.2  yamt  * by Matt Thomas of 3am Software Foundry.
      9  1.2.4.2  yamt  *
     10  1.2.4.2  yamt  * Redistribution and use in source and binary forms, with or without
     11  1.2.4.2  yamt  * modification, are permitted provided that the following conditions
     12  1.2.4.2  yamt  * are met:
     13  1.2.4.2  yamt  * 1. Redistributions of source code must retain the above copyright
     14  1.2.4.2  yamt  *    notice, this list of conditions and the following disclaimer.
     15  1.2.4.2  yamt  * 2. Redistributions in binary form must reproduce the above copyright
     16  1.2.4.2  yamt  *    notice, this list of conditions and the following disclaimer in the
     17  1.2.4.2  yamt  *    documentation and/or other materials provided with the distribution.
     18  1.2.4.2  yamt  *
     19  1.2.4.2  yamt  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  1.2.4.2  yamt  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  1.2.4.2  yamt  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  1.2.4.2  yamt  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  1.2.4.2  yamt  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  1.2.4.2  yamt  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  1.2.4.2  yamt  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  1.2.4.2  yamt  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  1.2.4.2  yamt  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  1.2.4.2  yamt  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  1.2.4.2  yamt  * POSSIBILITY OF SUCH DAMAGE.
     30  1.2.4.2  yamt  */
     31  1.2.4.2  yamt 
     32  1.2.4.2  yamt #include <sys/cdefs.h>
     33  1.2.4.2  yamt #if defined(LIBC_SCCS) && !defined(lint)
     34  1.2.4.2  yamt __RCSID("$NetBSD: floatdisf_ieee754.c,v 1.2.4.2 2014/05/22 11:36:53 yamt Exp $");
     35  1.2.4.2  yamt #endif /* LIBC_SCCS and not lint */
     36  1.2.4.2  yamt 
     37  1.2.4.2  yamt #if defined(SOFTFLOAT) || defined(__ARM_EABI__)
     38  1.2.4.2  yamt #include "softfloat/softfloat-for-gcc.h"
     39  1.2.4.2  yamt #endif
     40  1.2.4.2  yamt 
     41  1.2.4.2  yamt #include <limits.h>
     42  1.2.4.2  yamt #include <machine/ieee.h>
     43  1.2.4.2  yamt #include "quad.h"
     44  1.2.4.2  yamt 
     45  1.2.4.2  yamt float __floatdisf(quad_t);
     46  1.2.4.2  yamt 
     47  1.2.4.2  yamt /*
     48  1.2.4.2  yamt  * Convert signed quad to float.
     49  1.2.4.2  yamt  */
     50  1.2.4.2  yamt float
     51  1.2.4.2  yamt __floatdisf(quad_t x)
     52  1.2.4.2  yamt {
     53  1.2.4.2  yamt 	union ieee_single_u ux = { .sngu_f = 0.0 };
     54  1.2.4.2  yamt 
     55  1.2.4.2  yamt 	if (x == 0)
     56  1.2.4.2  yamt 		return 0.0;
     57  1.2.4.2  yamt 	if (x == 1)
     58  1.2.4.2  yamt 		return 1.0;
     59  1.2.4.2  yamt 
     60  1.2.4.2  yamt 	if (x < 0) {
     61  1.2.4.2  yamt 		if (x == QUAD_MIN)
     62  1.2.4.2  yamt 			return -0x1.0p63;
     63  1.2.4.2  yamt 		ux.sngu_sign = 1;
     64  1.2.4.2  yamt 		x = -x;
     65  1.2.4.2  yamt 	}
     66  1.2.4.2  yamt #if defined(_LP64) || defined(__mips_n32)
     67  1.2.4.2  yamt 	u_int l = __builtin_clzll(x);
     68  1.2.4.2  yamt 	x <<= (l + 1);	/* clear implicit bit */
     69  1.2.4.2  yamt 
     70  1.2.4.2  yamt 	ux.sngu_frac = (u_quad_t)x >> (64 - SNG_FRACBITS);
     71  1.2.4.2  yamt #else
     72  1.2.4.2  yamt 	union uu u = { .uq = x };
     73  1.2.4.2  yamt 	uint32_t frac;
     74  1.2.4.2  yamt 	u_int l;
     75  1.2.4.2  yamt 	if (u.ul[H] == 0) {
     76  1.2.4.2  yamt 		l = __builtin_clz(u.ul[L]);
     77  1.2.4.2  yamt 		frac = u.ul[L] << (l + 1);	/* clear implicit bit */
     78  1.2.4.2  yamt 		l += 32;
     79  1.2.4.2  yamt 	} else {
     80  1.2.4.2  yamt 		l = __builtin_clz(u.ul[H]);
     81  1.2.4.2  yamt 		frac = u.ul[H] << (l + 1);	/* clear implicit bit */
     82  1.2.4.2  yamt 		frac |= u.ul[L] >> (32 - (l + 1));
     83  1.2.4.2  yamt 	}
     84  1.2.4.2  yamt 
     85  1.2.4.2  yamt 	ux.sngu_frac = frac >> (32 - SNG_FRACBITS);
     86  1.2.4.2  yamt #endif
     87  1.2.4.2  yamt 	ux.sngu_exp = SNG_EXP_BIAS + 63 - l;
     88  1.2.4.2  yamt 
     89  1.2.4.2  yamt 	return ux.sngu_f;
     90  1.2.4.2  yamt }
     91