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      1 /*	$NetBSD: fixunstfdi_ieee754.c,v 1.2 2024/01/05 09:41:58 rin Exp $	*/
      2 /*-
      3  * Copyright (c) 2011 The NetBSD Foundation, Inc.
      4  * All rights reserved.
      5  *
      6  * This code is derived from software contributed to The NetBSD Foundation
      7  * by Matt Thomas of 3am Software Foundry.
      8  *
      9  * Redistribution and use in source and binary forms, with or without
     10  * modification, are permitted provided that the following conditions
     11  * are met:
     12  * 1. Redistributions of source code must retain the above copyright
     13  *    notice, this list of conditions and the following disclaimer.
     14  * 2. Redistributions in binary form must reproduce the above copyright
     15  *    notice, this list of conditions and the following disclaimer in the
     16  *    documentation and/or other materials provided with the distribution.
     17  *
     18  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     19  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     20  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     21  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     22  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     23  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     24  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     25  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     26  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     27  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     28  * POSSIBILITY OF SUCH DAMAGE.
     29  */
     30 
     31 #include <sys/cdefs.h>
     32 
     33 #if defined(LIBC_SCCS) && !defined(lint)
     34 __RCSID("$NetBSD: fixunstfdi_ieee754.c,v 1.2 2024/01/05 09:41:58 rin Exp $");
     35 #endif /* LIBC_SCCS and not lint */
     36 
     37 #include <stdbool.h>
     38 #include <stddef.h>
     39 #include <stdint.h>
     40 #include <float.h>
     41 #include <machine/ieee.h>
     42 
     43 #if defined(__x86_64__) || defined(__i486__)
     44 #define	FIXUNS	__fixunsxfdi
     45 #else
     46 #define	FIXUNS	__fixunstfdi
     47 #endif
     48 
     49 uint64_t __fixunsgen64(int, bool, size_t, size_t, const uint32_t *);
     50 
     51 uint64_t FIXUNS(long double);
     52 
     53 /*
     54  * Convert long double to uint64_t.  All operations are done module 2^64.
     55  */
     56 uint64_t
     57 FIXUNS(long double x)
     58 {
     59 	const union ieee_ext_u extu = { .extu_ld = x };
     60 	uint32_t frac[(EXT_FRACBITS + 31)/32 + 2];
     61 
     62 	frac[0] = 0;
     63 	frac[1] = 0;
     64 
     65 	EXT_TO_ARRAY32(extu, &frac[2]);
     66 
     67 	return __fixunsgen64(
     68 		extu.extu_ext.ext_exp - EXT_EXP_BIAS,
     69 		extu.extu_ext.ext_sign != 0,
     70 		LDBL_MANT_DIG,
     71 		EXT_FRACHBITS,
     72 		&frac[__arraycount(frac)-1]);
     73 }
     74