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authorLasse Collin <lasse.collin@tukaani.org>2009-10-04 22:57:12 +0300
committerLasse Collin <lasse.collin@tukaani.org>2009-10-04 22:57:12 +0300
commitebfb2c5e1f344e5c6e549b9dedaa49b0749a4a24 (patch)
tree7e2f519ad2be01b8f9c7b230f71d479d550c9ae4 /m4
parentAdd support for --enable-assume-ram=SIZE. (diff)
downloadxz-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')
-rw-r--r--m4/tuklib_integer.m474
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