float.h revision 1.27 
1/*	$NetBSD: float.h,v 1.27 2025/10/07 02:15:36 nat Exp $	*/
2
3#ifndef _M68K_FLOAT_H_
4#define _M68K_FLOAT_H_
5
6#include <sys/featuretest.h>
7
8/*
9 * LDBL_MIN is half the x86 LDBL_MIN, even though both are 12-byte
10 * floats with the same base properties and both allegedly
11 * IEEE-compliant, because both these representations materialize the
12 * top (integer-part) bit of the significand.  But on m68k if the
13 * exponent is 0 and the integer bit is set, it's a regular number,
14 * whereas on x86 it's called a pseudo-denormal and apparently treated
15 * as a denormal, so it doesn't count as a valid value for LDBL_MIN.
16 *
17 * If you are running a softloat userland LDBL_MIN is half that again.
18 *
19 * x86 citation: Intel 64 and IA-32 Architectures Software Developer's
20 * Manual, vol. 1 (Order Number: 253665-077US, April 2022), Sec. 8.2.2
21 * `Unsupported Double Extended-Precision Floating-Point Encodings
22 * and Pseudo-Denormals', p. 8-14.
23 *
24 * m86k citation: MC68881/MC68882 Floating-Point Coprocessor User's
25 * Manual, Second Edition (Prentice-Hall, 1989, apparently issued by
26 * Freescale), Section 3.2 `Binary Real Data formats', pg. 3-3 bottom
27 * in particular and pp. 3-2 to 3-5 in general.
28 *
29 * If anyone needs to update this comment please make sure the copy in
30 * x86/include/float.h also gets updated.
31 */
32
33#if defined(__LDBL_MANT_DIG__) && \
34			!(defined(__m68k__) && !defined(__HAVE_68881__))
35#define LDBL_MANT_DIG	__LDBL_MANT_DIG__
36#define LDBL_EPSILON	__LDBL_EPSILON__
37#define LDBL_DIG	__LDBL_DIG__
38#define LDBL_MIN_EXP	__LDBL_MIN_EXP__
39#define LDBL_MIN	__LDBL_MIN__
40#define LDBL_MIN_10_EXP	__LDBL_MIN_10_EXP__
41#define LDBL_MAX_EXP	__LDBL_MAX_EXP__
42#define LDBL_MAX	__LDBL_MAX__
43#define LDBL_MAX_10_EXP	__LDBL_MAX_10_EXP__
44#elif !defined(__mc68010__) && !defined(__mcoldfire__)
45#define LDBL_MANT_DIG	64
46#define LDBL_EPSILON	1.0842021724855044340E-19L
47#define LDBL_DIG	18
48#if !defined(__HAVE_68881__)
49#define LDBL_MIN_EXP	(-16382)
50#define LDBL_MIN	0.8405257857780233760E-4932L
51#else
52#define LDBL_MIN_EXP	(-16381)
53#define LDBL_MIN	1.6810515715560467531E-4932L
54#endif
55#define LDBL_MIN_10_EXP	(-4931)
56#define LDBL_MAX_EXP	16384
57#define LDBL_MAX	1.1897314953572317650E+4932L
58#define LDBL_MAX_10_EXP	4932
59#endif
60
61#include <sys/float_ieee754.h>
62
63#if !defined(__mc68010__) && !defined(__mcoldfire__)
64#if !defined(_ANSI_SOURCE) && !defined(_POSIX_C_SOURCE) && \
65    !defined(_XOPEN_SOURCE) || \
66    ((__STDC_VERSION__ - 0) >= 199901L) || \
67    ((_POSIX_C_SOURCE - 0) >= 200112L) || \
68    ((_XOPEN_SOURCE  - 0) >= 600) || \
69    defined(_ISOC99_SOURCE) || defined(_NETBSD_SOURCE)
70#define	DECIMAL_DIG	21
71#endif /* !defined(_ANSI_SOURCE) && ... */
72#endif /* !__mc68010__ && !__mcoldfire__ */
73
74#endif	/* !_M68K_FLOAT_H_ */
75