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Edit File: ax_c_bigendian_cross.m4
# =========================================================================== # http://www.gnu.org/software/autoconf-archive/ax_c_bigendian_cross.html # =========================================================================== # # SYNOPSIS # # AX_C_BIGENDIAN_CROSS # # DESCRIPTION # # Check endianess even when crosscompiling (partially based on the # original AC_C_BIGENDIAN). # # The implementation will create a binary, but instead of running the # binary it will be grep'ed for some symbols that differ for different # endianess of the binary. # # NOTE: The upcoming autoconf 2.53 does include the idea of this macro, # what makes it superfluous by then. # # LICENSE # # Copyright (c) 2008 Guido U. Draheim <guidod@gmx.de> # # This program is free software; you can redistribute it and/or modify it # under the terms of the GNU General Public License as published by the # Free Software Foundation; either version 3 of the License, or (at your # option) any later version. # # This program is distributed in the hope that it will be useful, but # WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General # Public License for more details. # # You should have received a copy of the GNU General Public License along # with this program. If not, see <http://www.gnu.org/licenses/>. # # As a special exception, the respective Autoconf Macro's copyright owner # gives unlimited permission to copy, distribute and modify the configure # scripts that are the output of Autoconf when processing the Macro. You # need not follow the terms of the GNU General Public License when using # or distributing such scripts, even though portions of the text of the # Macro appear in them. The GNU General Public License (GPL) does govern # all other use of the material that constitutes the Autoconf Macro. # # This special exception to the GPL applies to versions of the Autoconf # Macro released by the Autoconf Archive. When you make and distribute a # modified version of the Autoconf Macro, you may extend this special # exception to the GPL to apply to your modified version as well. #serial 5 AU_ALIAS([AC_C_BIGENDIAN_CROSS], [AX_C_BIGENDIAN_CROSS]) AC_DEFUN([AX_C_BIGENDIAN_CROSS], [AC_CACHE_CHECK(whether byte ordering is bigendian, ac_cv_c_bigendian, [ac_cv_c_bigendian=unknown # See if sys/param.h defines the BYTE_ORDER macro. AC_TRY_COMPILE([#include <sys/types.h> #include <sys/param.h>], [ #if !BYTE_ORDER || !BIG_ENDIAN || !LITTLE_ENDIAN bogus endian macros #endif], [# It does; now see whether it defined to BIG_ENDIAN or not. AC_TRY_COMPILE([#include <sys/types.h> #include <sys/param.h>], [ #if BYTE_ORDER != BIG_ENDIAN not big endian #endif], ac_cv_c_bigendian=yes, ac_cv_c_bigendian=no)]) if test $ac_cv_c_bigendian = unknown; then AC_TRY_RUN([main () { /* Are we little or big endian? From Harbison&Steele. */ union { long l; char c[sizeof (long)]; } u; u.l = 1; exit (u.c[sizeof (long) - 1] == 1); }], ac_cv_c_bigendian=no, ac_cv_c_bigendian=yes, [ echo $ac_n "cross-compiling... " 2>&AC_FD_MSG ]) fi]) if test $ac_cv_c_bigendian = unknown; then AC_MSG_CHECKING(to probe for byte ordering) [ cat >conftest.c <<EOF short ascii_mm[] = { 0x4249, 0x4765, 0x6E44, 0x6961, 0x6E53, 0x7953, 0 }; short ascii_ii[] = { 0x694C, 0x5454, 0x656C, 0x6E45, 0x6944, 0x6E61, 0 }; void _ascii() { char* s = (char*) ascii_mm; s = (char*) ascii_ii; } short ebcdic_ii[] = { 0x89D3, 0xE3E3, 0x8593, 0x95C5, 0x89C4, 0x9581, 0 }; short ebcdic_mm[] = { 0xC2C9, 0xC785, 0x95C4, 0x8981, 0x95E2, 0xA8E2, 0 }; void _ebcdic() { char* s = (char*) ebcdic_mm; s = (char*) ebcdic_ii; } int main() { _ascii (); _ebcdic (); return 0; } EOF ] if test -f conftest.c ; then if ${CC-cc} -c conftest.c -o conftest.o && test -f conftest.o ; then if test `grep -l BIGenDianSyS conftest.o` ; then echo $ac_n ' big endian probe OK, ' 1>&AC_FD_MSG ac_cv_c_bigendian=yes fi if test `grep -l LiTTleEnDian conftest.o` ; then echo $ac_n ' little endian probe OK, ' 1>&AC_FD_MSG if test $ac_cv_c_bigendian = yes ; then ac_cv_c_bigendian=unknown; else ac_cv_c_bigendian=no fi fi echo $ac_n 'guessing bigendian ... ' >&AC_FD_MSG fi fi AC_MSG_RESULT($ac_cv_c_bigendian) fi if test $ac_cv_c_bigendian = yes; then AC_DEFINE(WORDS_BIGENDIAN, 1, [whether byteorder is bigendian]) BYTEORDER=4321 else BYTEORDER=1234 fi AC_DEFINE_UNQUOTED(BYTEORDER, $BYTEORDER, [1234 = LIL_ENDIAN, 4321 = BIGENDIAN]) if test $ac_cv_c_bigendian = unknown; then AC_MSG_ERROR(unknown endianess - sorry, please pre-set ac_cv_c_bigendian) fi ])