diff --git a/alloca.S b/driver/alloca_driver.S
similarity index 91%
rename from alloca.S
rename to driver/alloca_driver.S
index 7ad9b56..432709c 100644
--- a/alloca.S
+++ b/driver/alloca_driver.S
@@ -1,8 +1,4 @@
-.intel_syntax noprefix
-
-.macro  alloca size
-sub rsp, \size
-.endm
+.include "lib/alloca.S"
 
 .text
 
diff --git a/strcpy.S b/driver/strcpy_driver.S
similarity index 59%
rename from strcpy.S
rename to driver/strcpy_driver.S
index 2796c29..37de014 100644
--- a/strcpy.S
+++ b/driver/strcpy_driver.S
@@ -1,3 +1,5 @@
+    .include "lib/strcpy.S"
+
     .intel_syntax noprefix
 
     .globl _start
@@ -5,22 +7,6 @@
     .text
 
 
-# String-copying routine.
-# Commented-out lines would also return the starting address of the destination address.
-strcpy:
-#    push rsi
-.loop:
-    movb r10b, [rdi]
-    cmpb r10b, 0
-    je .end
-    movb [rsi], r10b
-    inc rdi
-    inc rsi
-    jmp .loop
-.end:
-#    pop rax
-    ret
-
 _start:
 
     mov rdi, offset str2
diff --git a/lib/alloca.S b/lib/alloca.S
new file mode 100644
index 0000000..707c4f0
--- /dev/null
+++ b/lib/alloca.S
@@ -0,0 +1,5 @@
+.intel_syntax noprefix
+
+.macro  alloca size
+sub rsp, \size
+.endm
diff --git a/lib/strcpy.S b/lib/strcpy.S
new file mode 100644
index 0000000..147e2eb
--- /dev/null
+++ b/lib/strcpy.S
@@ -0,0 +1,23 @@
+    .intel_syntax noprefix
+
+    .globl _start
+
+    .text
+
+
+# String-copying routine.
+# Commented-out lines would also return the starting address of the destination address.
+strcpy:
+#    push rsi
+.loop:
+    movb r10b, [rdi]
+    cmpb r10b, 0
+    je .end
+    movb [rsi], r10b
+    inc rdi
+    inc rsi
+    jmp .loop
+.end:
+#    pop rax
+    ret
+