diff --git a/acconfig.h b/acconfig.h
new file mode 100644
index 0000000..30f96b6
--- /dev/null
+++ b/acconfig.h
@@ -0,0 +1,13 @@
+
+/* Define if kernel is 64 bit and userland is 32 bit */
+#undef KERNEL64_USER32
+
+@BOTTOM@
+
+#include <sys/types.h>
+
+#ifdef KERNEL64_USER32
+typedef u_int64_t kptr_t;
+#else
+typedef void *kptr_t;
+#endif
diff --git a/configure.in b/configure.in
index f071944..a579257 100644
--- a/configure.in
+++ b/configure.in
@@ -2,8 +2,22 @@
 
 AC_INIT(Makefile.am)
 AM_INIT_AUTOMAKE(libraw1394, 0.6)
+AM_CONFIG_HEADER(config.h)
+
+# AC_CANONICAL_HOST
 
 AC_PROG_CC
 AM_PROG_LIBTOOL
 
+
+AC_ARG_ENABLE(32-64,
+              [  --enable-32-64          support systems with 64 bit kernel and 32 bit userland],
+              [
+case $enableval in
+yes) AC_DEFINE(KERNEL64_USER32) ;;
+no) ;;
+*) AC_MSG_ERROR([ Invalid arg for --enable-32-64 ])
+esac
+              ])
+
 AC_OUTPUT([ Makefile src/Makefile debian/Makefile ])
diff --git a/src/eventloop.c b/src/eventloop.c
index e898ba7..85c68b5 100644
--- a/src/eventloop.c
+++ b/src/eventloop.c
@@ -1,4 +1,5 @@
 
+#include <config.h>
 #include <unistd.h>
 
 #include "raw1394.h"
diff --git a/src/fcp.c b/src/fcp.c
index 2c56027..cf501c0 100644
--- a/src/fcp.c
+++ b/src/fcp.c
@@ -1,4 +1,5 @@
 
+#include <config.h>
 #include <errno.h>
 #include <unistd.h>
 
@@ -18,7 +19,7 @@ static int do_fcp_listen(struct raw1394_handle *handle, int startstop)
         req->generation = handle->generation;
         req->misc = startstop;
         req->tag = (unsigned long)&rh;
-        req->recvb = handle->buffer;
+        req->recvb = (kptr_t)handle->buffer;
         req->length = 512;
 
         err = write(handle->fd, req, sizeof(*req));
diff --git a/src/iso.c b/src/iso.c
index 21abeae..96ecd3c 100644
--- a/src/iso.c
+++ b/src/iso.c
@@ -1,4 +1,5 @@
 
+#include <config.h>
 #include <errno.h>
 #include <unistd.h>
 
@@ -19,7 +20,7 @@ static int do_iso_listen(struct raw1394_handle *handle, int channel)
         req->generation = handle->generation;
         req->misc = channel;
         req->tag = (unsigned long)&rh;
-        req->recvb = handle->buffer;
+        req->recvb = (kptr_t)handle->buffer;
         req->length = HBUF_SIZE;
 
         err = write(handle->fd, req, sizeof(*req));
diff --git a/src/kernel-raw1394.h b/src/kernel-raw1394.h
index f23bfc0..b17a033 100644
--- a/src/kernel-raw1394.h
+++ b/src/kernel-raw1394.h
@@ -56,8 +56,14 @@ struct raw1394_request {
         unsigned long tag;
 
         size_t length;
+
+#ifdef __KERNEL__
         quadlet_t *sendb;
         quadlet_t *recvb;
+#else
+        kptr_t sendb;
+        kptr_t recvb;
+#endif
 };
 
 struct raw1394_khost_list {
diff --git a/src/main.c b/src/main.c
index 16e08f1..3484d81 100644
--- a/src/main.c
+++ b/src/main.c
@@ -1,4 +1,5 @@
 
+#include <config.h>
 #include <errno.h>
 #include <stdlib.h>
 #include <string.h>
@@ -134,7 +135,7 @@ int raw1394_get_port_info(struct raw1394_handle *handle,
         CLEAR_REQ(req);
         req->type = RAW1394_REQ_LIST_CARDS;
         req->generation = handle->generation;
-        req->recvb = handle->buffer;
+        req->recvb = (kptr_t)handle->buffer;
         req->length = HBUF_SIZE;
 
         while (1) {
diff --git a/src/readwrite.c b/src/readwrite.c
index aa1db0e..d928e61 100644
--- a/src/readwrite.c
+++ b/src/readwrite.c
@@ -1,4 +1,5 @@
 
+#include <config.h>
 #include <unistd.h>
 #include <errno.h>
 
@@ -21,7 +22,7 @@ int raw1394_start_read(struct raw1394_handle *handle, nodeid_t node,
 
         req->address = ((u_int64_t)node << 48) | addr;
         req->length = length;
-        req->recvb = buffer;
+        req->recvb = (kptr_t)buffer;
 
         return (int)write(handle->fd, req, sizeof(*req));
 }
@@ -40,7 +41,7 @@ int raw1394_start_write(struct raw1394_handle *handle, nodeid_t node,
 
         req->address = ((u_int64_t)node << 48) | addr;
         req->length = length;
-        req->sendb = data;
+        req->sendb = (kptr_t)data;
 
         return (int)write(handle->fd, req, sizeof(*req));
 }
@@ -64,8 +65,8 @@ int raw1394_start_lock(struct raw1394_handle *handle, nodeid_t node,
         req->tag = tag;
 
         req->address = ((u_int64_t)node << 48) | addr;
-        req->sendb = sendbuf;
-        req->recvb = result;
+        req->sendb = (kptr_t)sendbuf;
+        req->recvb = (kptr_t)result;
         req->misc = extcode;
 
         switch (extcode) {