| 1 | dnl @synopsis AX_CHECK_NONALIGNED_ACCESS |
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| 2 | dnl |
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| 3 | dnl This macro will see if non-aligned memory accesses will fail. The following |
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| 4 | dnl defines will be made as appropriate: |
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| 5 | dnl HAVE_ALIGNED_ONLY_INT16 |
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| 6 | dnl HAVE_ALIGNED_ONLY_INT32 |
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| 7 | dnl HAVE_ALIGNED_ONLY_INT64 |
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| 8 | dnl |
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| 9 | dnl @category C |
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| 10 | dnl @author Martin Ebourne |
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| 11 | dnl @version 2005/07/12 |
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| 12 | dnl @license AllPermissive |
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| 13 | |
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| 14 | AC_DEFUN([AX_CHECK_NONALIGNED_ACCESS], [ |
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| 15 | AC_CACHE_CHECK([if non-aligned 16 bit word accesses fail], [box_cv_have_aligned_only_int16], |
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| 16 | [AC_RUN_IFELSE([AC_LANG_PROGRAM([[$ac_includes_default]], [[ |
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| 17 | #ifndef HAVE_UINT16_T |
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| 18 | #define uint16_t u_int16_t; |
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| 19 | #endif |
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| 20 | uint16_t scratch[2]; |
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| 21 | memset(scratch, 0, sizeof(scratch)); |
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| 22 | return *(uint16_t*)((char*)scratch+1); |
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| 23 | ]])], |
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| 24 | [box_cv_have_aligned_only_int16=no], [box_cv_have_aligned_only_int16=yes] |
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| 25 | )]) |
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| 26 | if test "x$box_cv_have_aligned_only_int16" = "xyes"; then |
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| 27 | AC_DEFINE([HAVE_ALIGNED_ONLY_INT16], 1, [Define to 1 if non-aligned int16 access will fail]) |
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| 28 | fi |
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| 29 | AC_CACHE_CHECK([if non-aligned 32 bit word accesses fail], [box_cv_have_aligned_only_int32], |
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| 30 | [AC_RUN_IFELSE([AC_LANG_PROGRAM([[$ac_includes_default]], [[ |
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| 31 | #ifndef HAVE_UINT32_T |
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| 32 | #define uint32_t u_int32_t; |
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| 33 | #endif |
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| 34 | uint32_t scratch[2]; |
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| 35 | memset(scratch, 0, sizeof(scratch)); |
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| 36 | return *(uint32_t*)((char*)scratch+1); |
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| 37 | ]])], |
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| 38 | [box_cv_have_aligned_only_int32=no], [box_cv_have_aligned_only_int32=yes] |
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| 39 | )]) |
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| 40 | if test "x$box_cv_have_aligned_only_int32" = "xyes"; then |
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| 41 | AC_DEFINE([HAVE_ALIGNED_ONLY_INT32], 1, [Define to 1 if non-aligned int32 access will fail]) |
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| 42 | fi |
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| 43 | AC_CACHE_CHECK([if non-aligned 64 bit word accesses fail], [box_cv_have_aligned_only_int64], |
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| 44 | [AC_RUN_IFELSE([AC_LANG_PROGRAM([[$ac_includes_default]], [[ |
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| 45 | #ifndef HAVE_UINT64_T |
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| 46 | #define uint64_t u_int64_t; |
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| 47 | #endif |
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| 48 | uint64_t scratch[2]; |
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| 49 | memset(scratch, 0, sizeof(scratch)); |
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| 50 | return *(uint64_t*)((char*)scratch+1); |
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| 51 | ]])], |
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| 52 | [box_cv_have_aligned_only_int64=no], [box_cv_have_aligned_only_int64=yes] |
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| 53 | )]) |
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| 54 | if test "x$box_cv_have_aligned_only_int64" = "xyes"; then |
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| 55 | AC_DEFINE([HAVE_ALIGNED_ONLY_INT64], 1, [Define to 1 if non-aligned int64 access will fail]) |
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| 56 | fi |
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| 57 | ])dnl |
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