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| author | Lasse Collin <lasse.collin@tukaani.org> | 2009-10-04 22:57:12 +0300 |
|---|---|---|
| committer | Lasse Collin <lasse.collin@tukaani.org> | 2009-10-04 22:57:12 +0300 |
| commit | ebfb2c5e1f344e5c6e549b9dedaa49b0749a4a24 (patch) | |
| tree | 7e2f519ad2be01b8f9c7b230f71d479d550c9ae4 /m4/tuklib_integer.m4 | |
| parent | Add support for --enable-assume-ram=SIZE. (diff) | |
| download | xz-ebfb2c5e1f344e5c6e549b9dedaa49b0749a4a24.tar.xz | |
Use a tuklib module for integer handling.
This replaces bswap.h and integer.h.
The tuklib module uses <byteswap.h> on GNU,
<sys/endian.h> on *BSDs and <sys/byteorder.h>
on Solaris, which may contain optimized code
like inline assembly.
Diffstat (limited to 'm4/tuklib_integer.m4')
| -rw-r--r-- | m4/tuklib_integer.m4 | 74 |
1 files changed, 74 insertions, 0 deletions
diff --git a/m4/tuklib_integer.m4 b/m4/tuklib_integer.m4 new file mode 100644 index 00000000..5fe66eef --- /dev/null +++ b/m4/tuklib_integer.m4 @@ -0,0 +1,74 @@ +# +# SYNOPSIS +# +# TUKLIB_INTEGER +# +# DESCRIPTION +# +# Checks for tuklib_integer.h: +# - Endianness +# - Does operating system provide byte swapping macros +# - Does the hardware support fast unaligned access to 16-bit +# and 32-bit integers +# +# COPYING +# +# Author: Lasse Collin +# +# This file has been put into the public domain. +# You can do whatever you want with this file. +# + +AC_DEFUN_ONCE([TUKLIB_INTEGER], [ +AC_REQUIRE([TUKLIB_COMMON]) +AC_REQUIRE([AC_C_BIGENDIAN]) +AC_CHECK_HEADERS([byteswap.h sys/endian.h sys/byteorder.h], [break]) + +# Even if we have byteswap.h, we may lack the specific macros/functions. +if test x$ac_cv_header_byteswap_h = xyes ; then + m4_foreach([FUNC], [bswap_16,bswap_32,bswap_64], [ + AC_MSG_CHECKING([if FUNC is available]) + AC_LINK_IFELSE([AC_LANG_SOURCE([ +#include <byteswap.h> +int +main(void) +{ + FUNC[](42); + return 0; +} + ])], [ + AC_DEFINE(HAVE_[]m4_toupper(FUNC), [1], + [Define to 1 if] FUNC [is available.]) + AC_MSG_RESULT([yes]) + ], [AC_MSG_RESULT([no])]) + + ])dnl +fi + +AC_MSG_CHECKING([if unaligned memory access should be used]) +AC_ARG_ENABLE([unaligned-access], AC_HELP_STRING([--enable-unaligned-access], + [Enable if the system supports *fast* unaligned memory access + with 16-bit and 32-bit integers. By default, this is enabled + only on x86, x86_64, and big endian PowerPC.]), + [], [enable_unaligned_access=auto]) +if test "x$enable_unaligned_access" = xauto ; then + # TODO: There may be other architectures, on which unaligned access + # is OK. + case $host_cpu in + i?86|x86_64|powerpc|powerpc64) + enable_unaligned_access=yes + ;; + *) + enable_unaligned_access=no + ;; + esac +fi +if test "x$enable_unaligned_access" = xyes ; then + AC_DEFINE([TUKLIB_FAST_UNALIGNED_ACCESS], [1], [Define to 1 if + the system supports fast unaligned access to 16-bit and + 32-bit integers.]) + AC_MSG_RESULT([yes]) +else + AC_MSG_RESULT([no]) +fi +])dnl |