| b.liu | e958203 | 2025-04-17 19:18:16 +0800 | [diff] [blame] | 1 | dnl AS_UNALIGNED_ACCESS |
| 2 | |
| 3 | dnl check if unaligned memory access works correctly |
| 4 | AC_DEFUN([AS_UNALIGNED_ACCESS], [ |
| 5 | AC_MSG_CHECKING([if unaligned memory access works correctly]) |
| 6 | if test x"$as_cv_unaligned_access" = x ; then |
| 7 | case $host in |
| 8 | alpha*|arm*|hp*|mips*|sh*|sparc*|ia64*) |
| 9 | _AS_ECHO_N([(blacklisted) ]) |
| 10 | as_cv_unaligned_access=no |
| 11 | ;; |
| 12 | i?86*|x86_64|amd64|powerpc*|m68k*|cris*) |
| 13 | _AS_ECHO_N([(whitelisted) ]) |
| 14 | as_cv_unaligned_access=yes |
| 15 | ;; |
| 16 | esac |
| 17 | else |
| 18 | _AS_ECHO_N([(cached) ]) |
| 19 | fi |
| 20 | if test x"$as_cv_unaligned_access" = x ; then |
| 21 | AC_TRY_RUN([ |
| 22 | int main(int argc, char **argv) |
| 23 | { |
| 24 | char array[] = "ABCDEFGH"; |
| 25 | unsigned int iarray[2]; |
| 26 | memcpy(iarray,array,8); |
| 27 | #define GET(x) (*(unsigned int *)((char *)iarray + (x))) |
| 28 | if(GET(0) != 0x41424344 && GET(0) != 0x44434241) return 1; |
| 29 | if(GET(1) != 0x42434445 && GET(1) != 0x45444342) return 1; |
| 30 | if(GET(2) != 0x43444546 && GET(2) != 0x46454443) return 1; |
| 31 | if(GET(3) != 0x44454647 && GET(3) != 0x47464544) return 1; |
| 32 | return 0; |
| 33 | } |
| 34 | ], as_cv_unaligned_access="yes", as_cv_unaligned_access="no") |
| 35 | fi |
| 36 | AC_MSG_RESULT($as_cv_unaligned_access) |
| 37 | if test "$as_cv_unaligned_access" = "yes"; then |
| 38 | AC_DEFINE_UNQUOTED(HAVE_UNALIGNED_ACCESS, 1, |
| 39 | [defined if unaligned memory access works correctly]) |
| 40 | fi |
| 41 | ]) |