1 dnl @synopsis AC_C_BIGENDIAN_CROSS 2 dnl 3 dnl Check endianess even when crosscompiling 4 dnl (partially based on the original AC_C_BIGENDIAN). 5 dnl 6 dnl The implementation will create a binary, and instead of running 7 dnl the binary it will be grep'ed for some symbols that will look 8 dnl different for different endianess of the binary. 9 dnl 10 dnl @version $Id: ac_c_bigendian_cross.m4,v 1.2 2001/10/01 20:03:13 fdrake Exp $ 11 dnl @author Guido Draheim <guidod (a] gmx.de> 12 dnl 13 AC_DEFUN([AC_C_BIGENDIAN_CROSS], 14 [AC_CACHE_CHECK(whether byte ordering is bigendian, ac_cv_c_bigendian, 15 [ac_cv_c_bigendian=unknown 16 # See if sys/param.h defines the BYTE_ORDER macro. 17 AC_TRY_COMPILE([#include <sys/types.h> 18 #include <sys/param.h>], [ 19 #if !BYTE_ORDER || !BIG_ENDIAN || !LITTLE_ENDIAN 20 bogus endian macros 21 #endif], [# It does; now see whether it defined to BIG_ENDIAN or not. 22 AC_TRY_COMPILE([#include <sys/types.h> 23 #include <sys/param.h>], [ 24 #if BYTE_ORDER != BIG_ENDIAN 25 not big endian 26 #endif], ac_cv_c_bigendian=yes, ac_cv_c_bigendian=no)]) 27 if test $ac_cv_c_bigendian = unknown; then 28 AC_TRY_RUN([main () { 29 /* Are we little or big endian? From Harbison&Steele. */ 30 union 31 { 32 long l; 33 char c[sizeof (long)]; 34 } u; 35 u.l = 1; 36 exit (u.c[sizeof (long) - 1] == 1); 37 }], ac_cv_c_bigendian=no, ac_cv_c_bigendian=yes, 38 [ echo $ac_n "cross-compiling... " 2>&AC_FD_MSG ]) 39 fi]) 40 if test $ac_cv_c_bigendian = unknown; then 41 AC_MSG_CHECKING(to probe for byte ordering) 42 [ 43 cat >conftest.c <<EOF 44 short ascii_mm[] = { 0x4249, 0x4765, 0x6E44, 0x6961, 0x6E53, 0x7953, 0 }; 45 short ascii_ii[] = { 0x694C, 0x5454, 0x656C, 0x6E45, 0x6944, 0x6E61, 0 }; 46 void _ascii() { char* s = (char*) ascii_mm; s = (char*) ascii_ii; } 47 short ebcdic_ii[] = { 0x89D3, 0xE3E3, 0x8593, 0x95C5, 0x89C4, 0x9581, 0 }; 48 short ebcdic_mm[] = { 0xC2C9, 0xC785, 0x95C4, 0x8981, 0x95E2, 0xA8E2, 0 }; 49 void _ebcdic() { char* s = (char*) ebcdic_mm; s = (char*) ebcdic_ii; } 50 int main() { _ascii (); _ebcdic (); return 0; } 51 EOF 52 ] if test -f conftest.c ; then 53 if ${CC-cc} -c conftest.c -o conftest.o && test -f conftest.o ; then 54 if test `grep -l BIGenDianSyS conftest.o` ; then 55 echo $ac_n ' big endian probe OK, ' 1>&AC_FD_MSG 56 ac_cv_c_bigendian=yes 57 fi 58 if test `grep -l LiTTleEnDian conftest.o` ; then 59 echo $ac_n ' little endian probe OK, ' 1>&AC_FD_MSG 60 if test $ac_cv_c_bigendian = yes ; then 61 ac_cv_c_bigendian=unknown; 62 else 63 ac_cv_c_bigendian=no 64 fi 65 fi 66 echo $ac_n 'guessing bigendian ... ' >&AC_FD_MSG 67 fi 68 fi 69 AC_MSG_RESULT($ac_cv_c_bigendian) 70 fi 71 if test $ac_cv_c_bigendian = yes; then 72 AC_DEFINE(WORDS_BIGENDIAN, 1, [whether byteorder is bigendian]) 73 BYTEORDER=4321 74 else 75 BYTEORDER=1234 76 fi 77 AC_DEFINE_UNQUOTED(BYTEORDER, $BYTEORDER, [1234 = LIL_ENDIAN, 4321 = BIGENDIAN]) 78 if test $ac_cv_c_bigendian = unknown; then 79 AC_MSG_ERROR(unknown endianess - sorry, please pre-set ac_cv_c_bigendian) 80 fi 81 ]) 82
