xref: /netbsd-src/sys/arch/m68k/include/float.h (revision ccd9df534e375a4366c5b55f23782053c7a98d82)
1 /*	$NetBSD: float.h,v 1.23 2024/06/15 11:44:09 rillig Exp $	*/
2 
3 #ifndef _M68K_FLOAT_H_
4 #define _M68K_FLOAT_H_
5 
6 /*
7  * LDBL_MIN is half the x86 LDBL_MIN, even though both are 12-byte
8  * floats with the same base properties and both allegedly
9  * IEEE-compliant, because both these representations materialize the
10  * top (integer-part) bit of the mantissa. But on m68k if the exponent
11  * is 0 and the integer bit is set, it's a regular number, whereas on
12  * x86 it's called a pseudo-denormal and apparently treated as a
13  * denormal, so it doesn't count as a valid value for LDBL_MIN.
14  *
15  * x86 citation: Intel 64 and IA-32 Architectures Software Developer's
16  * Manual, vol. 1 (Order Number: 253665-077US, April 2022), Sec. 8.2.2
17  * `Unsupported Double Extended-Precision Floating-Point Encodings
18  * and Pseudo-Denormals', p. 8-14.
19  *
20  * m86k citation: MC68881/MC68882 Floating-Point Coprocessor User's
21  * Manual, Second Edition (Prentice-Hall, 1989, apparently issued by
22  * Freescale), Section 3.2 `Binary Real Data formats', pg. 3-3 bottom
23  * in particular and pp. 3-2 to 3-5 in general.
24  *
25  * If anyone needs to update this comment please make sure the copy in
26  * x86/include/float.h also gets updated.
27  */
28 
29 #if defined(__LDBL_MANT_DIG__)
30 #define LDBL_MANT_DIG	__LDBL_MANT_DIG__
31 #define LDBL_EPSILON	__LDBL_EPSILON__
32 #define LDBL_DIG	__LDBL_DIG__
33 #define LDBL_MIN_EXP	__LDBL_MIN_EXP__
34 #define LDBL_MIN	__LDBL_MIN__
35 #define LDBL_MIN_10_EXP	__LDBL_MIN_10_EXP__
36 #define LDBL_MAX_EXP	__LDBL_MAX_EXP__
37 #define LDBL_MAX	__LDBL_MAX__
38 #define LDBL_MAX_10_EXP	__LDBL_MAX_10_EXP__
39 #elif !defined(__mc68010__) && !defined(__mcoldfire__)
40 #define LDBL_MANT_DIG	64
41 #define LDBL_EPSILON	1.0842021724855044340E-19L
42 #define LDBL_DIG	18
43 #define LDBL_MIN_EXP	(-16381)
44 #define LDBL_MIN	1.6810515715560467531E-4932L
45 #define LDBL_MIN_10_EXP	(-4931)
46 #define LDBL_MAX_EXP	16384
47 #define LDBL_MAX	1.1897314953572317650E+4932L
48 #define LDBL_MAX_10_EXP	4932
49 #endif
50 
51 #include <sys/float_ieee754.h>
52 
53 #if !defined(__mc68010__) && !defined(__mcoldfire__)
54 #if !defined(_ANSI_SOURCE) && !defined(_POSIX_C_SOURCE) && \
55     !defined(_XOPEN_SOURCE) || \
56     ((__STDC_VERSION__ - 0) >= 199901L) || \
57     ((_POSIX_C_SOURCE - 0) >= 200112L) || \
58     ((_XOPEN_SOURCE  - 0) >= 600) || \
59     defined(_ISOC99_SOURCE) || defined(_NETBSD_SOURCE)
60 #define	DECIMAL_DIG	21
61 #endif /* !defined(_ANSI_SOURCE) && ... */
62 #endif /* !__mc68010__ && !__mcoldfire__ */
63 
64 #endif	/* !_M68K_FLOAT_H_ */
65