Let the exec function output something.

[matthijs/master-project/cλash.git] / Alu.hs

diff --git a/Alu.hs b/Alu.hs
index e9ddf5775869a4538ee064b120d0034e8730cf82..ca2dbe9180613a3db75b55843660299246f809aa 100644 (file)
--- a/Alu.hs
+++ b/Alu.hs
@@ -5,7 +5,7 @@ import qualified Sim
 main = Sim.simulate exec program initial_state
 mainIO = Sim.simulateIO exec initial_state
 
-dontcare = Low
+dontcare = DontCare
 
 program = [
             -- (addr, we, op)
@@ -43,8 +43,8 @@ register_bank (addr, High, d) s = -- Write
   where
     --Regs r0 r1 = s
     (r0, r1) = s
-    r0' = if addr == Low then d else r0
-    r1' = if addr == High then d else r1
+    r0' = case addr of Low -> d; High -> r0; otherwise -> dontcare
+    r1' = case addr of High -> d; Low -> r1; otherwise -> dontcare
     --s' = Regs r0' r1'
     s' = (r0', r1')
 
@@ -61,11 +61,11 @@ salu High a b s = (s, a `hwand` b)
 salu Low a b s = (s, a `hwor` b)
 
 type ExecState = (RegisterBankState, Bit, Bit)
-exec :: (RegAddr, Bit, AluOp) -> ExecState -> (ExecState, ())
+exec :: (RegAddr, Bit, AluOp) -> ExecState -> (ExecState, (Bit))
 
 -- Read & Exec
 exec (addr, Low, op) s =
-  (s', ())
+  (s', z')
   where
     (reg_s, t, z) = s
     (reg_s', t') = register_bank (addr, Low, dontcare) reg_s
@@ -74,7 +74,7 @@ exec (addr, Low, op) s =
 
 -- Write
 exec (addr, High, op) s =
-  (s', ())
+  (s', dontcare)
   where
     (reg_s, t, z) = s
     (reg_s', _) = register_bank (addr, High, z) reg_s