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tuklib_integer.m4: Optimize the check order.
The __builtin byteswapping is the preferred one so check for it first.
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1 changed files with 29 additions and 27 deletions
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@ -7,7 +7,7 @@
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#
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# Checks for tuklib_integer.h:
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# - Endianness
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# - Does operating system provide byte swapping macros
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# - Does the compiler or the operating system provide byte swapping macros
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# - Does the hardware support fast unaligned access to 16-bit
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# and 32-bit integers
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#
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@ -22,9 +22,24 @@
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AC_DEFUN_ONCE([TUKLIB_INTEGER], [
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AC_REQUIRE([TUKLIB_COMMON])
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AC_REQUIRE([AC_C_BIGENDIAN])
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AC_MSG_CHECKING([if __builtin_bswap16/32/64 are supported])
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AC_LINK_IFELSE([AC_LANG_PROGRAM([[]],
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[[__builtin_bswap16(1);
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__builtin_bswap32(1);
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__builtin_bswap64(1);]])],
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[
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AC_DEFINE([HAVE___BUILTIN_BSWAPXX], [1],
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[Define to 1 if the GNU C extensions
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__builtin_bswap16/32/64 are supported.])
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AC_MSG_RESULT([yes])
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], [
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AC_MSG_RESULT([no])
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# Look for other byteswapping methods.
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AC_CHECK_HEADERS([byteswap.h sys/endian.h sys/byteorder.h], [break])
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# Even if we have byteswap.h, we may lack the specific macros/functions.
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# Even if we have byteswap.h we may lack the specific macros/functions.
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if test x$ac_cv_header_byteswap_h = xyes ; then
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m4_foreach([FUNC], [bswap_16,bswap_32,bswap_64], [
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AC_MSG_CHECKING([if FUNC is available])
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@ -44,19 +59,6 @@ main(void)
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])dnl
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fi
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AC_MSG_CHECKING([if __builtin_bswap16/32/64 are supported])
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AC_LINK_IFELSE([AC_LANG_PROGRAM([[]],
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[[__builtin_bswap16(1);
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__builtin_bswap32(1);
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__builtin_bswap64(1);]])],
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[
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AC_DEFINE([HAVE___BUILTIN_BSWAPXX], [1],
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[Define to 1 if the GNU C extensions
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__builtin_bswap16/32/64 are supported.])
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AC_MSG_RESULT([yes])
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], [
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AC_MSG_RESULT([no])
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])
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AC_MSG_CHECKING([if unaligned memory access should be used])
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