source: trunk/poppler/expat-1.95.8/conftools/ac_c_bigendian_cross.m4 @ 14

Last change on this file since 14 was 2, checked in by Eugene Romanenko, 16 years ago

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1dnl @synopsis AC_C_BIGENDIAN_CROSS
2dnl
3dnl Check endianess even when crosscompiling
4dnl (partially based on the original AC_C_BIGENDIAN).
5dnl
6dnl The implementation will create a binary, and instead of running
7dnl the binary it will be grep'ed for some symbols that will look
8dnl different for different endianess of the binary.
9dnl
10dnl @version $Id: ac_c_bigendian_cross.m4,v 1.2 2001/10/01 20:03:13 fdrake Exp $
11dnl @author Guido Draheim <guidod@gmx.de>
12dnl
13AC_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.
17AC_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.
22AC_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)])
27if test $ac_cv_c_bigendian = unknown; then
28AC_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 ])
39fi])
40if test $ac_cv_c_bigendian = unknown; then
41AC_MSG_CHECKING(to probe for byte ordering)
42[
43cat >conftest.c <<EOF
44short ascii_mm[] = { 0x4249, 0x4765, 0x6E44, 0x6961, 0x6E53, 0x7953, 0 };
45short ascii_ii[] = { 0x694C, 0x5454, 0x656C, 0x6E45, 0x6944, 0x6E61, 0 };
46void _ascii() { char* s = (char*) ascii_mm; s = (char*) ascii_ii; }
47short ebcdic_ii[] = { 0x89D3, 0xE3E3, 0x8593, 0x95C5, 0x89C4, 0x9581, 0 };
48short ebcdic_mm[] = { 0xC2C9, 0xC785, 0x95C4, 0x8981, 0x95E2, 0xA8E2, 0 };
49void _ebcdic() { char* s = (char*) ebcdic_mm; s = (char*) ebcdic_ii; }
50int main() { _ascii (); _ebcdic (); return 0; }
51EOF
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 $ac_n 'guessing bigendian ...  ' >&AC_FD_MSG
67     fi
68  fi
69AC_MSG_RESULT($ac_cv_c_bigendian)
70fi
71if test $ac_cv_c_bigendian = yes; then
72  AC_DEFINE(WORDS_BIGENDIAN, 1, [whether byteorder is bigendian])
73  BYTEORDER=4321
74else
75  BYTEORDER=1234
76fi
77AC_DEFINE_UNQUOTED(BYTEORDER, $BYTEORDER, [1234 = LIL_ENDIAN, 4321 = BIGENDIAN])
78if test $ac_cv_c_bigendian = unknown; then
79  AC_MSG_ERROR(unknown endianess - sorry, please pre-set ac_cv_c_bigendian)
80fi
81])
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