From 8e34ad7563ec54b3606fd530da0b4268d662740a Mon Sep 17 00:00:00 2001
From: pacien
Date: Mon, 30 Apr 2018 18:48:42 +0200
Subject: Implement eurm compilation stage 3 and 4

---
 src/eurm.ml | 46 ++++++++++++++++++++++++++++++++++++----------
 1 file changed, 36 insertions(+), 10 deletions(-)

diff --git a/src/eurm.ml b/src/eurm.ml
index 0caabf0..2b8cc5b 100644
--- a/src/eurm.ml
+++ b/src/eurm.ml
@@ -37,6 +37,11 @@ let build_initial_state eurmcmds =
     label_count = List.fold_left (fun acc instr -> acc + (match instr with | Label(_) -> 1 | _ -> 0)) 0 eurmcmds
   }
 
+let add_reg_label state new_regs new_labels = {
+  max_reg = state.max_reg + new_regs;
+  label_count = state.label_count + new_labels
+}
+
 let rec apply_transform transform_func state = function
   | [] -> [], state
   | cmd :: tail ->
@@ -49,29 +54,29 @@ let compile_stage1 eurmcmds state =
     | Dec(r) ->
       let new_reg = state.max_reg + 1
       in [ Zero(new_reg); Inc(new_reg); Sub(r, new_reg) ],
-         { max_reg = new_reg; label_count = state.label_count }
+         add_reg_label state 1 0
 
     | GEqPredicate(r1, r2, l) ->
       let new_reg = state.max_reg + 1
       in [ Copy(new_reg, r1); Inc(new_reg); GTPredicate(new_reg, r2, l) ],
-         { max_reg = new_reg; label_count = state.label_count }
+         add_reg_label state 1 0
 
     | LEqPredicate(r1, r2, l) ->
       let new_reg = state.max_reg + 1
       in [ Copy(new_reg, r2); Inc(new_reg); GTPredicate(new_reg, r1, l) ],
-         { max_reg = new_reg; label_count = state.label_count }
+         add_reg_label state 1 0
 
     | Mult(r1, r2) ->
       let ctr_reg = state.max_reg + 1 and res_reg = state.max_reg + 2
       and start_label = string_of_int (state.label_count + 1) and end_label = string_of_int (state.label_count + 2)
       in [ Zero(ctr_reg); Zero(res_reg); Label(start_label); EqPredicate(ctr_reg, r2, end_label);
            Add(res_reg, r1); Inc(ctr_reg); Goto(start_label); Label(end_label) ],
-         { max_reg = state.max_reg + 2; label_count = state.label_count + 2}
+         add_reg_label state 2 2
 
     | ZeroPredicate(r, l) ->
       let new_reg = state.max_reg + 1
       in [ Zero(new_reg); EqPredicate(r, new_reg, l) ],
-         { max_reg = new_reg; label_count = state.label_count }
+         add_reg_label state 1 0
 
     | LTPredicate(r1, r2, l) -> [ GTPredicate(r2, r1, l) ], state
     | any -> [ any ], state
@@ -85,14 +90,14 @@ let compile_stage2 eurmcmds state =
       and start_label = string_of_int (state.label_count + 1) and end_label = string_of_int (state.label_count + 2)
       in [ Zero(ctr_reg); Label(start_label); EqPredicate(ctr_reg, r2, end_label);
            Inc(r1); Inc(ctr_reg); Goto(start_label); Label(end_label) ],
-         { max_reg = state.label_count + 1; label_count = state.label_count + 2 }
+         add_reg_label state 1 2
 
     | GTPredicate(r1, r2, l) ->
       let aux_reg = state.max_reg + 1
       and start_label = string_of_int (state.label_count + 1) and end_label = string_of_int (state.label_count + 2)
       in [ Zero(aux_reg); Label(start_label); EqPredicate(aux_reg, r1, end_label); EqPredicate(aux_reg, r2, l);
            Inc(aux_reg); Goto(start_label); Label(end_label) ],
-         { max_reg = state.label_count + 1; label_count = state.label_count + 2 }
+         add_reg_label state 1 2
 
     | Sub(r1, r2) ->
       let diff_reg = state.max_reg + 1 and aux1_reg = state.max_reg + 2 and aux2_reg = state.max_reg + 3
@@ -102,14 +107,35 @@ let compile_stage2 eurmcmds state =
            EqPredicate(aux1_reg, r2, error_label); EqPredicate(aux2_reg, r1, end_label);
            Inc(diff_reg); Inc(aux1_reg); Inc(aux2_reg); Goto(start_label);
            Label(error_label); Quit; Label(end_label); Copy(r1, diff_reg) ],
-         { max_reg = state.label_count + 3; label_count = state.label_count + 3 }
+         add_reg_label state 3 3
+
+    | any -> [ any ], state
 
+  in apply_transform (transform) state eurmcmds
+
+let compile_stage3 eurmcmds state =
+  let transform = function
+    | Goto(lbl) ->
+      let dummy_reg = state.max_reg + 1
+      in [ Zero(dummy_reg); EqPredicate(dummy_reg, dummy_reg, lbl) ],
+         add_reg_label state 1 0
     | any -> [ any ], state
 
   in apply_transform (transform) state eurmcmds
 
-let compile_stage3 eurmcmds state = eurmcmds, state
-let compile_stage4 eurmcmds state = [URMZero(0)], state
+let compile_stage4 eurmcmds state =
+  let label_table = Hashtbl.create 100
+  in let build_label_table =
+       List.iteri (fun lineo cmd -> match cmd with | Label(lbl) -> Hashtbl.add label_table lbl lineo | _ -> ())
+  in let transform = function
+    | Inc(r) -> [ URMSucc(r) ], state
+    | Zero(r) -> [ URMZero(r) ], state
+    | EqPredicate(r1, r2, lbl) -> [ URMJump(r1, r2, Hashtbl.find label_table lbl) ], state
+    | Label(_) ->
+      let dummy_reg = state.max_reg + 1
+      in [ URMZero(dummy_reg) ], add_reg_label state 1 0
+    | _ -> failwith "Invalid_argument"
+  in build_label_table eurmcmds; apply_transform (transform) state eurmcmds
 
 let urm_from_eurm eurmcmds =
   let chain transform (eurmcmds, compile_state) = transform eurmcmds compile_state
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