diff --git a/DwarfSynth.mlpack b/DwarfSynth.mlpack
index b4deb07..1eeb434 100644
--- a/DwarfSynth.mlpack
+++ b/DwarfSynth.mlpack
@@ -4,3 +4,4 @@ PreDwarf
 Regs
 OnlyUnwind
 Simplest
+Frontend
diff --git a/DwarfSynth/Frontend.ml b/DwarfSynth/Frontend.ml
new file mode 100644
index 0000000..5c01857
--- /dev/null
+++ b/DwarfSynth/Frontend.ml
@@ -0,0 +1,44 @@
+(** Frontend
+    Clean printers, etc.
+ *)
+
+let pp_int64_hex ppx number =
+  let mask_short = Int64.(pred (shift_left one 16)) in
+  let pp_short number =
+    Format.fprintf ppx "%04x" Int64.(to_int (logand number mask_short))
+  in
+  List.iter pp_short @@ List.map (fun x ->
+      Int64.(shift_right number (16*x))) [3;2;1;0]
+
+let pp_cfa_change ppx (Simplest.CfaChange (addr, pos)) = Simplest.(
+    let num_len num =
+      let str_rep = Format.sprintf "%+d" num in
+      String.length str_rep
+    in
+    let print_row cfa_reg int64_offset =
+      let offset = Int64.to_int int64_offset in
+      let post_offset_spaces = String.make (6 - num_len offset) ' ' in
+      Format.fprintf ppx "%a %s%+d%sc-8@."
+        pp_int64_hex addr cfa_reg offset post_offset_spaces
+    in
+
+    match pos with
+    | RspOffset offset ->
+      print_row "rsp" offset
+    | RbpOffset offset ->
+      print_row "rbp" offset
+    | CfaLostTrack ->
+      Format.fprintf ppx "%a u        u@." pp_int64_hex addr
+  )
+
+let pp_pre_dwarf_readelf ppx pre_dwarf =
+  Simplest.StrMap.iter (fun fde_name entry ->
+      Format.fprintf ppx "FDE %s@." fde_name ;
+      (match entry with
+       | [] -> ()
+       | _ ->
+         Format.fprintf ppx "   LOC           CFA      ra@." ;
+         List.iter (pp_cfa_change ppx) entry ;
+         Format.fprintf ppx "@.")
+    )
+    pre_dwarf
diff --git a/DwarfSynth/Main.ml b/DwarfSynth/Main.ml
index 08f3836..877cd18 100644
--- a/DwarfSynth/Main.ml
+++ b/DwarfSynth/Main.ml
@@ -2,4 +2,4 @@ open Std
 
 let main outfile proj =
   let pre_dwarf = Simplest.of_proj proj in
-  Format.printf "%a" Simplest.pp_cfa_changes pre_dwarf
+  Format.printf "%a" Frontend.pp_pre_dwarf_readelf pre_dwarf
diff --git a/_tags b/_tags
index 606a539..251debe 100644
--- a/_tags
+++ b/_tags
@@ -6,3 +6,4 @@ true: bin_annot
 <DwarfSynth/Regs.cmx>: for-pack(DwarfSynth)
 <DwarfSynth/OnlyUnwind.cmx>: for-pack(DwarfSynth)
 <DwarfSynth/Simplest.cmx>: for-pack(DwarfSynth)
+<DwarfSynth/Frontend.cmx>: for-pack(DwarfSynth)