diff --git a/src/io_a.asm b/src/io_a.asm
index dcf2f82..9fe1ade 100644
--- a/src/io_a.asm
+++ b/src/io_a.asm
@@ -16,3 +16,19 @@ _io_out:
 
     pop ix
     ret
+
+PUBLIC _io_in
+_io_in:
+    push    ix
+    ld      ix,$0000
+    add     ix,sp
+
+    push    bc
+
+    ld      c,(ix+$04)
+    in      l,(c)
+
+    pop     bc
+
+    pop     ix
+    ret