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 1.1.1.1 2012/02/21 23:00:54 misho Exp $
11: dnl @author Guido Draheim <guidod@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: ])
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