diff --git a/libc/tools/gensyscalls.py b/libc/tools/gensyscalls.py
index 01c580f..d78a5e7 100755
--- a/libc/tools/gensyscalls.py
+++ b/libc/tools/gensyscalls.py
@@ -489,6 +489,14 @@
         if arch_list == "all":
             for arch in all_arches:
                 t[arch] = True
+        elif arch_list == "lp32":
+            for arch in all_arches:
+                if "64" not in arch:
+                    t[arch] = True
+        elif arch_list == "lp64":
+            for arch in all_arches:
+                if "64" in arch:
+                    t[arch] = True
         else:
             for arch in string.split(arch_list, ','):
                 if arch in all_arches: