| 1 | # isfinite.m4 serial 13 |
| 2 | dnl Copyright (C) 2007-2013 Free Software Foundation, Inc. |
| 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 | ]) |