Erik de Castro Lopo | 11efaa3 | 2013-03-10 12:30:49 +1100 | [diff] [blame] | 1 | dnl Copyright (C) 2012 Xiph.org Foundation |
| 2 | dnl |
| 3 | dnl Redistribution and use in source and binary forms, with or without |
| 4 | dnl modification, are permitted provided that the following conditions |
| 5 | dnl are met: |
| 6 | dnl |
| 7 | dnl - Redistributions of source code must retain the above copyright |
| 8 | dnl notice, this list of conditions and the following disclaimer. |
| 9 | dnl |
| 10 | dnl - Redistributions in binary form must reproduce the above copyright |
| 11 | dnl notice, this list of conditions and the following disclaimer in the |
| 12 | dnl documentation and/or other materials provided with the distribution. |
| 13 | dnl |
| 14 | dnl - Neither the name of the Xiph.org Foundation nor the names of its |
| 15 | dnl contributors may be used to endorse or promote products derived from |
| 16 | dnl this software without specific prior written permission. |
| 17 | dnl |
| 18 | dnl THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| 19 | dnl ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| 20 | dnl LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| 21 | dnl A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR |
| 22 | dnl CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, |
| 23 | dnl EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, |
| 24 | dnl PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR |
| 25 | dnl PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF |
| 26 | dnl LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING |
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| 28 | dnl SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| 29 | |
| 30 | |
| 31 | dnl @synopsis XIPH_C_FIND_ENDIAN |
| 32 | dnl |
| 33 | dnl Determine endian-ness of target processor. |
| 34 | dnl @version 1.1 Mar 03 2002 |
| 35 | dnl @author Erik de Castro Lopo <erikd@mega-nerd.com> |
| 36 | dnl |
| 37 | dnl Majority written from scratch to replace the standard autoconf macro |
| 38 | dnl AC_C_BIGENDIAN. Only part remaining from the original is the invocation |
| 39 | dnl of the AC_TRY_RUN macro. |
| 40 | dnl |
| 41 | dnl Find endian-ness in the following way: |
| 42 | dnl 1) Look in <endian.h>. |
| 43 | dnl 2) If 1) fails, look in <sys/types.h> and <sys/param.h>. |
| 44 | dnl 3) If 1) and 2) fails and not cross compiling run a test program. |
| 45 | dnl 4) If 1) and 2) fails and cross compiling then guess based on target. |
| 46 | |
| 47 | AC_DEFUN([XIPH_C_FIND_ENDIAN], |
| 48 | [AC_CACHE_CHECK(processor byte ordering, |
| 49 | ac_cv_c_byte_order, |
| 50 | |
| 51 | # Initialize to unknown |
| 52 | ac_cv_c_byte_order=unknown |
| 53 | |
| 54 | if test x$ac_cv_header_endian_h = xyes ; then |
| 55 | |
| 56 | # First try <endian.h> which should set BYTE_ORDER. |
| 57 | |
| 58 | [AC_TRY_LINK([ |
| 59 | #include <endian.h> |
| 60 | #if BYTE_ORDER != LITTLE_ENDIAN |
| 61 | not big endian |
| 62 | #endif |
| 63 | ], return 0 ;, |
| 64 | ac_cv_c_byte_order=little |
| 65 | )] |
| 66 | |
| 67 | [AC_TRY_LINK([ |
| 68 | #include <endian.h> |
| 69 | #if BYTE_ORDER != BIG_ENDIAN |
| 70 | not big endian |
| 71 | #endif |
| 72 | ], return 0 ;, |
| 73 | ac_cv_c_byte_order=big |
| 74 | )] |
| 75 | |
| 76 | fi |
| 77 | |
| 78 | if test $ac_cv_c_byte_order = unknown ; then |
| 79 | |
| 80 | [AC_TRY_LINK([ |
| 81 | #include <sys/types.h> |
| 82 | #include <sys/param.h> |
| 83 | #if !BYTE_ORDER || !BIG_ENDIAN || !LITTLE_ENDIAN |
| 84 | bogus endian macros |
| 85 | #endif |
| 86 | ], return 0 ;, |
| 87 | |
| 88 | [AC_TRY_LINK([ |
| 89 | #include <sys/types.h> |
| 90 | #include <sys/param.h> |
| 91 | #if BYTE_ORDER != LITTLE_ENDIAN |
| 92 | not big endian |
| 93 | #endif |
| 94 | ], return 0 ;, |
| 95 | ac_cv_c_byte_order=little |
| 96 | )] |
| 97 | |
| 98 | [AC_TRY_LINK([ |
| 99 | #include <sys/types.h> |
| 100 | #include <sys/param.h> |
| 101 | #if BYTE_ORDER != LITTLE_ENDIAN |
| 102 | not big endian |
| 103 | #endif |
| 104 | ], return 0 ;, |
| 105 | ac_cv_c_byte_order=little |
| 106 | )] |
| 107 | |
| 108 | )] |
| 109 | |
| 110 | fi |
| 111 | |
| 112 | if test $ac_cv_c_byte_order = unknown ; then |
| 113 | if test $cross_compiling = yes ; then |
| 114 | # This is the last resort. Try to guess the target processor endian-ness |
| 115 | # by looking at the target CPU type. |
| 116 | [ |
| 117 | case "$target_cpu" in |
| 118 | alpha* | i?86* | mipsel* | ia64*) |
| 119 | ac_cv_c_byte_order=little |
| 120 | ;; |
| 121 | |
| 122 | m68* | mips* | powerpc* | hppa* | sparc*) |
| 123 | ac_cv_c_byte_order=big |
| 124 | ;; |
| 125 | |
| 126 | esac |
| 127 | ] |
| 128 | else |
| 129 | AC_TRY_RUN( |
| 130 | [[ |
| 131 | int main (void) |
| 132 | { /* Are we little or big endian? From Harbison&Steele. */ |
| 133 | union |
| 134 | { long l ; |
| 135 | char c [sizeof (long)] ; |
| 136 | } u ; |
| 137 | u.l = 1 ; |
| 138 | return (u.c [sizeof (long) - 1] == 1); |
| 139 | } |
| 140 | ]], , ac_cv_c_byte_order=big, |
| 141 | ) |
| 142 | |
| 143 | AC_TRY_RUN( |
| 144 | [[int main (void) |
| 145 | { /* Are we little or big endian? From Harbison&Steele. */ |
| 146 | union |
| 147 | { long l ; |
| 148 | char c [sizeof (long)] ; |
| 149 | } u ; |
| 150 | u.l = 1 ; |
| 151 | return (u.c [0] == 1); |
| 152 | }]], , ac_cv_c_byte_order=little, |
| 153 | ) |
| 154 | fi |
| 155 | fi |
| 156 | |
| 157 | ) |
| 158 | |
| 159 | if test $ac_cv_c_byte_order = big ; then |
| 160 | ac_cv_c_big_endian=1 |
| 161 | ac_cv_c_little_endian=0 |
| 162 | elif test $ac_cv_c_byte_order = little ; then |
| 163 | ac_cv_c_big_endian=0 |
| 164 | ac_cv_c_little_endian=1 |
| 165 | else |
| 166 | ac_cv_c_big_endian=0 |
| 167 | ac_cv_c_little_endian=0 |
| 168 | |
| 169 | AC_MSG_WARN([[*****************************************************************]]) |
| 170 | AC_MSG_WARN([[*** Not able to determine endian-ness of target processor. ]]) |
| 171 | AC_MSG_WARN([[*** The constants CPU_IS_BIG_ENDIAN and CPU_IS_LITTLE_ENDIAN in ]]) |
| 172 | AC_MSG_WARN([[*** config.h may need to be hand editied. ]]) |
| 173 | AC_MSG_WARN([[*****************************************************************]]) |
| 174 | fi |
| 175 | |
| 176 | ] |
| 177 | )# XIPH_C_FIND_ENDIAN |