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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