diff --git a/3-lang0ll/.gitignore b/3-lang0ll/.gitignore
index c44e039..6c88159 100644
--- a/3-lang0ll/.gitignore
+++ b/3-lang0ll/.gitignore
@@ -2,5 +2,6 @@
 /lang0ll*.exe
 /lang0ll*.ll
 /lang0ll*.o
+/lang0ll*.s
 /foo.exe
 /foo.ll
diff --git a/3-lang0ll/backup.ll b/3-lang0ll/backup.ll
new file mode 100644
index 0000000..9413949
--- /dev/null
+++ b/3-lang0ll/backup.ll
@@ -0,0 +1,71 @@
+target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-pc-linux-gnu"
+
+declare noalias i8* @malloc(i64)
+
+define i8* @__add(i8* %lft, i8* %rgt)
+{
+    %lft_len = call i64 @__strlen(i8* %lft)
+    %rgt_len = call i64 @__strlen(i8* %rgt)
+    %new_len = add i64 %lft_len, %rgt_len
+
+    %res = call i8* @malloc(i64 %new_len)
+    ; todo: copy lft
+    ; todo: copy rgt
+    ; todo: set 0 byte
+    ret i8* %res
+}
+
+define i64 @__strlen(i8* %str)
+{
+start:
+    br label %loop_start
+
+loop_start:
+    %i.0 = phi i64 [0, %start], [%i.new, %loop]
+    %c_adr = getelementptr i8, i8* %str, i64 %i.0
+    %c = load i8, i8* %c_adr
+    %done = icmp eq i8 %c, 0
+    br i1 %done, label %exit, label %loop
+
+loop:
+    %i.new = add i64 %i.0, 1
+    br label %loop_start
+
+exit:
+    ret i64 %i.0
+}
+
+define i8* @__mapgetkey(i8* %mapname, i8* %key, i8* %def)
+{
+    ; todo
+    ret i8* %def
+}
+
+define i8* @addstringchar(i8* %0, i8* %1)
+{
+    ; todo
+    ret i8* %0
+}
+
+define i8* @registerid(i8* %id_id)
+{
+    %id_idname = call i8* @__mapgetkey(i8* noundef getelementptr inbounds ([14 x i8], [14 x i8]* @str.01, i64 0, i64 0), i8* %id_id, i8* noundef getelementptr inbounds ([14 x i8], [14 x i8]* @str.011, i64 0, i64 0))
+    %1 = call i64 @__strlen(i8* %id_idname)
+    %11 = icmp ne i64 %1, 0
+    br i1 %11, label %lbl1, label %lbl11
+lbl1:
+        ret i8* %id_idname
+lbl11:
+    %id_idnamea = call i8* @__add(i8* noundef getelementptr inbounds ([14 x i8], [14 x i8]* @str.0111, i64 0, i64 0), i8* %id_id)
+    ret i8* %id_idnamea
+}
+
+define i64 @main() {
+    %res = call i64 @__strlen(i8* @str.01)
+    ret i64 %res
+}
+
+@str.01 = internal constant [11 x i8] c"REGISTERID\00"
+@str.011 = internal constant [0 x i8] c""
+@str.0111 = internal constant [3 x i8] c"id_"