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Diffstat (limited to 'm4/endian.m4')
| -rw-r--r-- | m4/endian.m4 | 169 |
1 files changed, 169 insertions, 0 deletions
diff --git a/m4/endian.m4 b/m4/endian.m4 new file mode 100644 index 0000000..28fbf32 --- /dev/null +++ b/m4/endian.m4 @@ -0,0 +1,169 @@ +dnl Copyright (C) 2012-2023 Xiph.Org Foundation +dnl +dnl Redistribution and use in source and binary forms, with or without +dnl modification, are permitted provided that the following conditions +dnl are met: +dnl +dnl - Redistributions of source code must retain the above copyright +dnl notice, this list of conditions and the following disclaimer. +dnl +dnl - Redistributions in binary form must reproduce the above copyright +dnl notice, this list of conditions and the following disclaimer in the +dnl documentation and/or other materials provided with the distribution. +dnl +dnl - Neither the name of the Xiph.org Foundation nor the names of its +dnl contributors may be used to endorse or promote products derived from +dnl this software without specific prior written permission. +dnl +dnl THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +dnl ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +dnl LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR +dnl A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR +dnl CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, +dnl EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, +dnl PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR +dnl PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF +dnl LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING +dnl NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS +dnl SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + + +dnl @synopsis XIPH_C_FIND_ENDIAN +dnl +dnl Determine endian-ness of target processor. +dnl @version 1.1 Mar 03 2002 +dnl @author Erik de Castro Lopo <erikd@mega-nerd.com> +dnl +dnl Majority written from scratch to replace the standard autoconf macro +dnl AC_C_BIGENDIAN. Only part remaining from the original is the invocation +dnl of the AC_RUN_IFELSE([AC_LANG_SOURCE([[]])],[],[],[]) macro. +dnl +dnl Find endian-ness in the following way: +dnl 1) Look in <endian.h>. +dnl 2) If 1) fails, look in <sys/types.h> and <sys/param.h>. +dnl 3) If 1) and 2) fails and not cross compiling run a test program. +dnl 4) If 1) and 2) fails and cross compiling then guess based on target. + +AC_DEFUN([XIPH_C_FIND_ENDIAN], +[AC_CACHE_CHECK(processor byte ordering, + ac_cv_c_byte_order, + +# Initialize to unknown +ac_cv_c_byte_order=unknown + +if test x$ac_cv_header_endian_h = xyes ; then + + # First try <endian.h> which should set BYTE_ORDER. + + [AC_LINK_IFELSE([AC_LANG_PROGRAM([[ + #include <endian.h> + #if BYTE_ORDER != LITTLE_ENDIAN + not big endian + #endif + ]], [[return 0 ;]])],[ac_cv_c_byte_order=little + ],[])] + + [AC_LINK_IFELSE([AC_LANG_PROGRAM([[ + #include <endian.h> + #if BYTE_ORDER != BIG_ENDIAN + not big endian + #endif + ]], [[return 0 ;]])],[ac_cv_c_byte_order=big + ],[])] + + fi + +if test $ac_cv_c_byte_order = unknown ; then + + [AC_LINK_IFELSE([AC_LANG_PROGRAM([[ + #include <sys/types.h> + #include <sys/param.h> + #if !BYTE_ORDER || !BIG_ENDIAN || !LITTLE_ENDIAN + bogus endian macros + #endif + ]], [[return 0 ;]])],[_au_m4_changequote([,])AC_TRY_LINK([ + #include <sys/types.h> + #include <sys/param.h> + #if BYTE_ORDER != LITTLE_ENDIAN + not big endian + #endif + ], return 0 ;, + ac_cv_c_byte_order=little + ) + + _au_m4_changequote([,])AC_TRY_LINK([ + #include <sys/types.h> + #include <sys/param.h> + #if BYTE_ORDER != LITTLE_ENDIAN + not big endian + #endif + ], return 0 ;, + ac_cv_c_byte_order=little + ) + + ],[])] + + fi + +if test $ac_cv_c_byte_order = unknown ; then + if test $cross_compiling = yes ; then + # This is the last resort. Try to guess the target processor endian-ness + # by looking at the target CPU type. + [ + case "$target_cpu" in + alpha* | i?86* | mipsel* | ia64*) + ac_cv_c_byte_order=little + ;; + + m68* | mips* | powerpc* | hppa* | sparc*) + ac_cv_c_byte_order=big + ;; + + esac + ] + else + AC_RUN_IFELSE([AC_LANG_SOURCE([[[ + int main (void) + { /* Are we little or big endian? From Harbison&Steele. */ + union + { long l ; + char c [sizeof (long)] ; + } u ; + u.l = 1 ; + return (u.c [sizeof (long) - 1] == 1); + } + ]]])],[],[ac_cv_c_byte_order=big],[]) + + AC_RUN_IFELSE([AC_LANG_SOURCE([[[int main (void) + { /* Are we little or big endian? From Harbison&Steele. */ + union + { long l ; + char c [sizeof (long)] ; + } u ; + u.l = 1 ; + return (u.c [0] == 1); + }]]])],[],[ac_cv_c_byte_order=little],[]) + fi + fi + +) + +if test $ac_cv_c_byte_order = big ; then + ac_cv_c_big_endian=1 + ac_cv_c_little_endian=0 +elif test $ac_cv_c_byte_order = little ; then + ac_cv_c_big_endian=0 + ac_cv_c_little_endian=1 +else + ac_cv_c_big_endian=0 + ac_cv_c_little_endian=0 + + AC_MSG_WARN([[*****************************************************************]]) + AC_MSG_WARN([[*** Not able to determine endian-ness of target processor. ]]) + AC_MSG_WARN([[*** The constants CPU_IS_BIG_ENDIAN and CPU_IS_LITTLE_ENDIAN in ]]) + AC_MSG_WARN([[*** config.h may need to be hand editied. ]]) + AC_MSG_WARN([[*****************************************************************]]) + fi + +] +)# XIPH_C_FIND_ENDIAN |