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dnl AS_UNALIGNED_ACCESS
dnl check if unaligned memory access works correctly
AC_DEFUN([AS_UNALIGNED_ACCESS], [
AC_MSG_CHECKING([if unaligned memory access works correctly])
if test x"$as_cv_unaligned_access" = x ; then
case $host in
alpha*|arm*|hp*|mips*|sh*|sparc*|ia64*)
_AS_ECHO_N([(blacklisted) ])
as_cv_unaligned_access=no
;;
i?86*|powerpc*|m68k*)
_AS_ECHO_N([(whitelisted) ])
as_cv_unaligned_access=yes
;;
esac
else
_AS_ECHO_N([(cached) ])
fi
if test x"$as_cv_unaligned_access" = x ; then
AC_TRY_RUN([
int main(int argc, char **argv)
{
char array[] = "ABCDEFGH";
unsigned int iarray[2];
memcpy(iarray,array,8);
#define GET(x) (*(unsigned int *)((char *)iarray + (x)))
if(GET(0) != 0x41424344 && GET(0) != 0x44434241) return 1;
if(GET(1) != 0x42434445 && GET(1) != 0x45444342) return 1;
if(GET(2) != 0x43444546 && GET(2) != 0x46454443) return 1;
if(GET(3) != 0x44454647 && GET(3) != 0x47464544) return 1;
return 0;
}
], as_cv_unaligned_access="yes", as_cv_unaligned_access="no")
fi
AC_MSG_RESULT($as_cv_unaligned_access)
if test "$as_cv_unaligned_access" = "yes"; then
AC_DEFINE_UNQUOTED(HAVE_UNALIGNED_ACCESS, 1,
[defined if unaligned memory access works correctly])
fi
])
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