xref: /netbsd-src/lib/libc/gen/fixunstfdi_ieee754.c (revision b1652dc39bc0357243d5093c6545f95b6454766b)
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
FIXUNS(long double x)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