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42 lines
1.3 KiB
Plaintext
42 lines
1.3 KiB
Plaintext
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dnl AS_UNALIGNED_ACCESS
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dnl check if unaligned memory access works correctly
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AC_DEFUN([AS_UNALIGNED_ACCESS], [
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AC_MSG_CHECKING([if unaligned memory access works correctly])
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if test x"$as_cv_unaligned_access" = x ; then
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case $host in
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alpha*|arm*|hp*|mips*|sh*|sparc*|ia64*)
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_AS_ECHO_N([(blacklisted) ])
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as_cv_unaligned_access=no
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;;
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i?86*|x86_64|amd64|powerpc*|m68k*|cris*)
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_AS_ECHO_N([(whitelisted) ])
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as_cv_unaligned_access=yes
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;;
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esac
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else
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_AS_ECHO_N([(cached) ])
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fi
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if test x"$as_cv_unaligned_access" = x ; then
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AC_TRY_RUN([
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int main(int argc, char **argv)
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{
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char array[] = "ABCDEFGH";
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unsigned int iarray[2];
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memcpy(iarray,array,8);
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#define GET(x) (*(unsigned int *)((char *)iarray + (x)))
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if(GET(0) != 0x41424344 && GET(0) != 0x44434241) return 1;
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if(GET(1) != 0x42434445 && GET(1) != 0x45444342) return 1;
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if(GET(2) != 0x43444546 && GET(2) != 0x46454443) return 1;
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if(GET(3) != 0x44454647 && GET(3) != 0x47464544) return 1;
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return 0;
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}
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], as_cv_unaligned_access="yes", as_cv_unaligned_access="no")
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fi
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AC_MSG_RESULT($as_cv_unaligned_access)
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if test "$as_cv_unaligned_access" = "yes"; then
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AC_DEFINE_UNQUOTED(HAVE_UNALIGNED_ACCESS, 1,
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[defined if unaligned memory access works correctly])
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fi
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])
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