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52414043 | 1 | # isfinite.m4 serial 13 |
5e69ceb7 | 2 | dnl Copyright (C) 2007-2014 Free Software Foundation, Inc. |
52414043 MW |
3 | dnl This file is free software; the Free Software Foundation |
4 | dnl gives unlimited permission to copy and/or distribute it, | |
5 | dnl with or without modifications, as long as this notice is preserved. | |
6 | ||
7 | AC_DEFUN([gl_ISFINITE], | |
8 | [ | |
9 | AC_REQUIRE([gl_MATH_H_DEFAULTS]) | |
10 | dnl Persuade glibc <math.h> to declare isfinite. | |
11 | AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS]) | |
12 | AC_CHECK_DECLS([isfinite], , , [[#include <math.h>]]) | |
13 | if test "$ac_cv_have_decl_isfinite" = yes; then | |
14 | gl_CHECK_MATH_LIB([ISFINITE_LIBM], | |
15 | [x = isfinite (x) + isfinite ((float) x);]) | |
16 | if test "$ISFINITE_LIBM" != missing; then | |
17 | dnl Test whether isfinite() on 'long double' works. | |
18 | gl_ISFINITEL_WORKS | |
19 | case "$gl_cv_func_isfinitel_works" in | |
20 | *yes) ;; | |
21 | *) ISFINITE_LIBM=missing;; | |
22 | esac | |
23 | dnl Also, isfinite() on 'double' does not work on Linux/ia64 (because of | |
24 | dnl signalling NaNs). But this does not have to be tested, since | |
25 | dnl isfinite(long double) also does not work in this situation. | |
26 | fi | |
27 | fi | |
28 | if test "$ac_cv_have_decl_isfinite" != yes || | |
29 | test "$ISFINITE_LIBM" = missing; then | |
30 | REPLACE_ISFINITE=1 | |
31 | dnl No libraries are needed to link lib/isfinite.c. | |
32 | ISFINITE_LIBM= | |
33 | fi | |
34 | AC_SUBST([ISFINITE_LIBM]) | |
35 | ]) | |
36 | ||
37 | dnl Test whether isfinite() on 'long double' recognizes all numbers which are | |
38 | dnl neither finite nor infinite. This test fails e.g. on i686, x86_64, ia64, | |
39 | dnl because of | |
40 | dnl - pseudo-denormals on x86_64, | |
41 | dnl - pseudo-zeroes, unnormalized numbers, and pseudo-denormals on i686, | |
42 | dnl - pseudo-NaN, pseudo-Infinity, pseudo-zeroes, unnormalized numbers, and | |
43 | dnl pseudo-denormals on ia64. | |
44 | AC_DEFUN([gl_ISFINITEL_WORKS], | |
45 | [ | |
46 | AC_REQUIRE([AC_PROG_CC]) | |
47 | AC_REQUIRE([gl_BIGENDIAN]) | |
48 | AC_REQUIRE([gl_LONG_DOUBLE_VS_DOUBLE]) | |
49 | AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles | |
50 | AC_CACHE_CHECK([whether isfinite(long double) works], [gl_cv_func_isfinitel_works], | |
51 | [ | |
52 | AC_RUN_IFELSE([AC_LANG_SOURCE([[ | |
53 | #include <float.h> | |
54 | #include <limits.h> | |
55 | #include <math.h> | |
56 | #define NWORDS \ | |
57 | ((sizeof (long double) + sizeof (unsigned int) - 1) / sizeof (unsigned int)) | |
58 | typedef union { unsigned int word[NWORDS]; long double value; } | |
59 | memory_long_double; | |
60 | /* On Irix 6.5, gcc 3.4.3 can't compute compile-time NaN, and needs the | |
61 | runtime type conversion. */ | |
62 | #ifdef __sgi | |
63 | static long double NaNl () | |
64 | { | |
65 | double zero = 0.0; | |
66 | return zero / zero; | |
67 | } | |
68 | #else | |
69 | # define NaNl() (0.0L / 0.0L) | |
70 | #endif | |
71 | int main () | |
72 | { | |
73 | int result = 0; | |
74 | ||
75 | { | |
76 | memory_long_double m; | |
77 | unsigned int i; | |
78 | ||
79 | /* The isfinite macro should be immune against changes in the sign bit and | |
80 | in the mantissa bits. The xor operation twiddles a bit that can only be | |
81 | a sign bit or a mantissa bit (since the exponent never extends to | |
82 | bit 31). */ | |
83 | m.value = NaNl (); | |
84 | m.word[NWORDS / 2] ^= (unsigned int) 1 << (sizeof (unsigned int) * CHAR_BIT - 1); | |
85 | for (i = 0; i < NWORDS; i++) | |
86 | m.word[i] |= 1; | |
87 | if (isfinite (m.value)) | |
88 | result |= 1; | |
89 | } | |
90 | ||
91 | #if ((defined __ia64 && LDBL_MANT_DIG == 64) || (defined __x86_64__ || defined __amd64__) || (defined __i386 || defined __i386__ || defined _I386 || defined _M_IX86 || defined _X86_)) && !HAVE_SAME_LONG_DOUBLE_AS_DOUBLE | |
92 | /* Representation of an 80-bit 'long double' as an initializer for a sequence | |
93 | of 'unsigned int' words. */ | |
94 | # ifdef WORDS_BIGENDIAN | |
95 | # define LDBL80_WORDS(exponent,manthi,mantlo) \ | |
96 | { ((unsigned int) (exponent) << 16) | ((unsigned int) (manthi) >> 16), \ | |
97 | ((unsigned int) (manthi) << 16) | (unsigned int) (mantlo) >> 16), \ | |
98 | (unsigned int) (mantlo) << 16 \ | |
99 | } | |
100 | # else | |
101 | # define LDBL80_WORDS(exponent,manthi,mantlo) \ | |
102 | { mantlo, manthi, exponent } | |
103 | # endif | |
104 | { /* Quiet NaN. */ | |
105 | static memory_long_double x = | |
106 | { LDBL80_WORDS (0xFFFF, 0xC3333333, 0x00000000) }; | |
107 | if (isfinite (x.value)) | |
108 | result |= 2; | |
109 | } | |
110 | { | |
111 | /* Signalling NaN. */ | |
112 | static memory_long_double x = | |
113 | { LDBL80_WORDS (0xFFFF, 0x83333333, 0x00000000) }; | |
114 | if (isfinite (x.value)) | |
115 | result |= 2; | |
116 | } | |
117 | /* The isfinite macro should recognize Pseudo-NaNs, Pseudo-Infinities, | |
118 | Pseudo-Zeroes, Unnormalized Numbers, and Pseudo-Denormals, as defined in | |
119 | Intel IA-64 Architecture Software Developer's Manual, Volume 1: | |
120 | Application Architecture. | |
121 | Table 5-2 "Floating-Point Register Encodings" | |
122 | Figure 5-6 "Memory to Floating-Point Register Data Translation" | |
123 | */ | |
124 | { /* Pseudo-NaN. */ | |
125 | static memory_long_double x = | |
126 | { LDBL80_WORDS (0xFFFF, 0x40000001, 0x00000000) }; | |
127 | if (isfinite (x.value)) | |
128 | result |= 4; | |
129 | } | |
130 | { /* Pseudo-Infinity. */ | |
131 | static memory_long_double x = | |
132 | { LDBL80_WORDS (0xFFFF, 0x00000000, 0x00000000) }; | |
133 | if (isfinite (x.value)) | |
134 | result |= 8; | |
135 | } | |
136 | { /* Pseudo-Zero. */ | |
137 | static memory_long_double x = | |
138 | { LDBL80_WORDS (0x4004, 0x00000000, 0x00000000) }; | |
139 | if (isfinite (x.value)) | |
140 | result |= 16; | |
141 | } | |
142 | { /* Unnormalized number. */ | |
143 | static memory_long_double x = | |
144 | { LDBL80_WORDS (0x4000, 0x63333333, 0x00000000) }; | |
145 | if (isfinite (x.value)) | |
146 | result |= 32; | |
147 | } | |
148 | { /* Pseudo-Denormal. */ | |
149 | static memory_long_double x = | |
150 | { LDBL80_WORDS (0x0000, 0x83333333, 0x00000000) }; | |
151 | if (isfinite (x.value)) | |
152 | result |= 64; | |
153 | } | |
154 | #endif | |
155 | ||
156 | return result; | |
157 | }]])], [gl_cv_func_isfinitel_works=yes], [gl_cv_func_isfinitel_works=no], | |
158 | [case "$host_cpu" in | |
159 | # Guess no on ia64, x86_64, i386. | |
160 | ia64 | x86_64 | i*86) gl_cv_func_isfinitel_works="guessing no";; | |
161 | *) gl_cv_func_isfinitel_works="guessing yes";; | |
162 | esac | |
163 | ]) | |
164 | ]) | |
165 | ]) |