diff --git a/libc/include/sys/param.h b/libc/include/sys/param.h
index 0bfdc5d..27acd70 100644
--- a/libc/include/sys/param.h
+++ b/libc/include/sys/param.h
@@ -34,8 +34,13 @@
 #define MAXPATHLEN  PATH_MAX
 #define MAXSYMLINKS 8
 
-#define ALIGNBYTES  3
-#define ALIGN(p)    (((unsigned int)(p) + ALIGNBYTES) &~ ALIGNBYTES)
+#if __LP64__
+#define ALIGNBYTES 7
+#else
+#define ALIGNBYTES 3
+#endif
+
+#define ALIGN(p)    (((unsigned long)(p) + ALIGNBYTES) &~ ALIGNBYTES)
 
 #define powerof2(x) ((((x)-1)&(x))==0)