userland: add ported to all archs

userland/arch/x86_64/add.S

@@ -0,0 +1,9 @@
+/* https://github.com/cirosantilli/linux-kernel-module-cheat#userland-assembly */
+
+#include "common.h"
+
+ENTRY
+    mov $1, %rax
+    add $2, %rax
+    ASSERT_EQ(%rax, $3)
+EXIT

userland/arch/x86_64/common_arch.h

@@ -9,9 +9,9 @@
     mov reg, %rax; \
     mov const, %rbx; \
     cmp %rax, %rbx; \
-    ASSERT(je); \
     pop %rbx; \
     pop %rax; \
+    ASSERT(je); \
 ;
 
 # TODO