X-Git-Url: https://git.liburcu.org/?p=urcu.git;a=blobdiff_plain;f=configure.ac;h=a4e675fca1f87aa2262a638566f1bf8414dd9794;hp=422b11b31f721a7ba32adc3a6e55d52067e1a3ee;hb=90586875e92a9cdc6c7088d8e9815a6a0f54beb1;hpb=e156285068a631eaafa643d9e930b31780468d00

diff --git a/configure.ac b/configure.ac
index 422b11b..a4e675f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -10,6 +10,8 @@ AM_INIT_AUTOMAKE([foreign dist-bzip2 no-dist-gzip])
 AC_CONFIG_SRCDIR([urcu.h])
 
 AH_TEMPLATE([CONFIG_SMP], [Enable SMP support. With SMP support enabled, uniprocessors are also supported. With SMP support disabled, UP systems work fine, but the behavior of SMP systems is undefined.])
+AH_TEMPLATE([CONFIG_HAVE_FENCE], [Defined when on a system that has memory fence
+instructions.])
 AC_CONFIG_HEADERS([config.h])
 
 # Checks for programs.
@@ -49,6 +51,15 @@ fi
 AC_SUBST(ARCHTYPE)
 AC_SUBST(SUBARCHTYPE)
 
+[
+if test "x$ARCHTYPE" = "xx86" -a "x$target_cpu" != "xi386" -a "x$target_cpu" !=
+"xi486" -a "x$target_cpu" != "xi586"; then
+]
+	AC_DEFINE([CONFIG_HAVE_FENCE], [1])
+[
+fi
+]
+
 AM_CONDITIONAL([GCC_API], [test "x$ARCHTYPE" != xx86 -a "x$ARCHTYPE" != xppc])
 
 AM_CONDITIONAL([COMPAT_ARCH], [test "x$SUBARCHTYPE" == xx86compat ])