| 1 | dnl @synopsis AC_C_BIGENDIAN_CROSS |
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| 2 | dnl |
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| 3 | dnl Check endianess even when crosscompiling (partially based on the |
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| 4 | dnl original AC_C_BIGENDIAN). |
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| 5 | dnl |
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| 6 | dnl The implementation will create a binary, but instead of running the |
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| 7 | dnl binary it will be grep'ed for some symbols that differ for |
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| 8 | dnl different endianess of the binary. |
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| 9 | dnl |
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| 10 | dnl NOTE: The upcoming autoconf 2.53 does include the idea of this |
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| 11 | dnl macro, what makes it superfluous by then. |
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| 12 | dnl |
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| 13 | dnl @category CrossCompilation |
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| 14 | dnl @author Guido Draheim <guidod@gmx.de> |
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| 15 | dnl @version 2002-03-18 |
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| 16 | dnl @license GPLWithACException |
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| 17 | |
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| 18 | AC_DEFUN([AC_C_BIGENDIAN_CROSS], |
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| 19 | [AC_CACHE_CHECK(whether byte ordering is bigendian, ac_cv_c_bigendian, |
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| 20 | [ac_cv_c_bigendian=unknown |
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| 21 | # See if sys/param.h defines the BYTE_ORDER macro. |
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| 22 | AC_TRY_COMPILE([#include <sys/types.h> |
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| 23 | #include <sys/param.h>], [ |
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| 24 | #if !BYTE_ORDER || !BIG_ENDIAN || !LITTLE_ENDIAN |
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| 25 | bogus endian macros |
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| 26 | #endif], [# It does; now see whether it defined to BIG_ENDIAN or not. |
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| 27 | AC_TRY_COMPILE([#include <sys/types.h> |
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| 28 | #include <sys/param.h>], [ |
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| 29 | #if BYTE_ORDER != BIG_ENDIAN |
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| 30 | not big endian |
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| 31 | #endif], ac_cv_c_bigendian=yes, ac_cv_c_bigendian=no)]) |
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| 32 | if test $ac_cv_c_bigendian = unknown; then |
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| 33 | AC_TRY_RUN([main () { |
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| 34 | /* Are we little or big endian? From Harbison&Steele. */ |
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| 35 | union |
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| 36 | { |
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| 37 | long l; |
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| 38 | char c[sizeof (long)]; |
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| 39 | } u; |
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| 40 | u.l = 1; |
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| 41 | exit (u.c[sizeof (long) - 1] == 1); |
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| 42 | }], ac_cv_c_bigendian=no, ac_cv_c_bigendian=yes, |
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| 43 | [ echo $ac_n "cross-compiling... " 2>&AC_FD_MSG ]) |
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| 44 | fi]) |
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| 45 | if test $ac_cv_c_bigendian = unknown; then |
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| 46 | AC_MSG_CHECKING(to probe for byte ordering) |
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| 47 | [ |
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| 48 | cat >conftest.c <<EOF |
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| 49 | short ascii_mm[] = { 0x4249, 0x4765, 0x6E44, 0x6961, 0x6E53, 0x7953, 0 }; |
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| 50 | short ascii_ii[] = { 0x694C, 0x5454, 0x656C, 0x6E45, 0x6944, 0x6E61, 0 }; |
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| 51 | void _ascii() { char* s = (char*) ascii_mm; s = (char*) ascii_ii; } |
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| 52 | short ebcdic_ii[] = { 0x89D3, 0xE3E3, 0x8593, 0x95C5, 0x89C4, 0x9581, 0 }; |
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| 53 | short ebcdic_mm[] = { 0xC2C9, 0xC785, 0x95C4, 0x8981, 0x95E2, 0xA8E2, 0 }; |
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| 54 | void _ebcdic() { char* s = (char*) ebcdic_mm; s = (char*) ebcdic_ii; } |
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| 55 | int main() { _ascii (); _ebcdic (); return 0; } |
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| 56 | EOF |
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| 57 | ] if test -f conftest.c ; then |
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| 58 | if ${CC-cc} -c conftest.c -o conftest.o && test -f conftest.o ; then |
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| 59 | if test `grep -l BIGenDianSyS conftest.o` ; then |
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| 60 | echo $ac_n ' big endian probe OK, ' 1>&AC_FD_MSG |
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| 61 | ac_cv_c_bigendian=yes |
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| 62 | fi |
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| 63 | if test `grep -l LiTTleEnDian conftest.o` ; then |
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| 64 | echo $ac_n ' little endian probe OK, ' 1>&AC_FD_MSG |
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| 65 | if test $ac_cv_c_bigendian = yes ; then |
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| 66 | ac_cv_c_bigendian=unknown; |
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| 67 | else |
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| 68 | ac_cv_c_bigendian=no |
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| 69 | fi |
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| 70 | fi |
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| 71 | echo $ac_n 'guessing bigendian ... ' >&AC_FD_MSG |
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| 72 | fi |
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| 73 | fi |
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| 74 | AC_MSG_RESULT($ac_cv_c_bigendian) |
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| 75 | fi |
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| 76 | if test $ac_cv_c_bigendian = yes; then |
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| 77 | AC_DEFINE(WORDS_BIGENDIAN, 1, [whether byteorder is bigendian]) |
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| 78 | BYTEORDER=4321 |
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| 79 | else |
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| 80 | BYTEORDER=1234 |
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| 81 | fi |
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| 82 | AC_DEFINE_UNQUOTED(BYTEORDER, $BYTEORDER, [1234 = LIL_ENDIAN, 4321 = BIGENDIAN]) |
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| 83 | if test $ac_cv_c_bigendian = unknown; then |
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| 84 | AC_MSG_ERROR(unknown endianess - sorry, please pre-set ac_cv_c_bigendian) |
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| 85 | fi |
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| 86 | ]) |
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