From 2ee391fd9b32f39872abfcf339e949f5139c6cbd Mon Sep 17 00:00:00 2001
From: Matthijs Kooijman <matthijs@stdin.nl>
Date: Wed, 4 Mar 2009 00:54:09 +0100
Subject: [PATCH] Remove support for DontCare.

---
 Alu.hs     |  6 +++---
 Bits.hs    |  2 +-
 Flatten.hs | 49 +++++++++++++++----------------------------------
 3 files changed, 19 insertions(+), 38 deletions(-)

diff --git a/Alu.hs b/Alu.hs
index ea9bae8..0fba340 100644
--- 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 = DontCare
+dontcare = Low
 
 program = [
             -- (addr, we, op)
@@ -43,8 +43,8 @@ register_bank (addr, High, d) s = -- Write
   where
     --Regs r0 r1 = s
     (r0, r1) = s
-    r0' = case addr of Low -> d; High -> r0; otherwise -> dontcare
-    r1' = case addr of High -> d; Low -> r1; otherwise -> dontcare
+    r0' = case addr of Low -> d; High -> r0
+    r1' = case addr of High -> d; Low -> r1
     --s' = Regs r0' r1'
     s' = (r0', r1')
 
diff --git a/Bits.hs b/Bits.hs
index c0717bf..99131d0 100644
--- a/Bits.hs
+++ b/Bits.hs
@@ -38,7 +38,7 @@ displaysig High = "1"
 displaysig Low  = "0"
 
 -- The plain Bit type
-data Bit = High | Low | DontCare
+data Bit = High | Low
   deriving (Show, Eq, Read)
 
 -- A function to prettyprint a bitvector
diff --git a/Flatten.hs b/Flatten.hs
index 325f742..4bb6e71 100644
--- a/Flatten.hs
+++ b/Flatten.hs
@@ -331,25 +331,20 @@ flattenExpr binds expr@(Case scrut b _ alts) = do
       (args', res') <- flattenMultipleAltCaseExpr binds scrut b (a':alts)
       case a of
         (DataAlt datacon, bind_vars, expr) -> do
-          if isDontCare datacon 
-            then do
-              -- Completely skip the dontcare cases
-              return (args', res')
-            else do
-              lit <- dataConToLiteral datacon
-              -- The scrutinee must be a single signal
-              let Single sig = scrut
-              -- Create a signal that contains a boolean
-              boolsigid <- genSignalId SigInternal TysWiredIn.boolTy
-              addNameHint ("s" ++ show sig ++ "_eq_" ++ lit) boolsigid
-              let expr = EqLit sig lit
-              addDef (UncondDef (Right expr) boolsigid)
-              -- Create conditional assignments of either args/res or
-              -- args'/res based on boolsigid, and return the result.
-              -- TODO: It seems this adds the name hint twice?
-              our_args <- Monad.zipWithM (mkConditionals boolsigid) args args'
-              our_res  <- mkConditionals boolsigid res res'
-              return (our_args, our_res)
+          lit <- dataConToLiteral datacon
+          -- The scrutinee must be a single signal
+          let Single sig = scrut
+          -- Create a signal that contains a boolean
+          boolsigid <- genSignalId SigInternal TysWiredIn.boolTy
+          addNameHint ("s" ++ show sig ++ "_eq_" ++ lit) boolsigid
+          let expr = EqLit sig lit
+          addDef (UncondDef (Right expr) boolsigid)
+          -- Create conditional assignments of either args/res or
+          -- args'/res based on boolsigid, and return the result.
+          -- TODO: It seems this adds the name hint twice?
+          our_args <- Monad.zipWithM (mkConditionals boolsigid) args args'
+          our_res  <- mkConditionals boolsigid res res'
+          return (our_args, our_res)
         otherwise ->
           error $ "Case patterns other than data constructors not supported in case alternative: " ++ (showSDoc $ ppr a)
       where
@@ -374,20 +369,6 @@ flattenExpr binds expr@(Case scrut b _ alts) = do
 flattenExpr _ expr = do
   error $ "Unsupported expression: " ++ (showSDoc $ ppr expr)
 
--- | Is the given data constructor a dontcare?
-isDontCare :: DataCon.DataCon -> Bool
-isDontCare datacon =
-  case Name.getOccString tyname of
-    -- TODO: Do something more robust than string matching
-    "Bit" ->
-      Name.getOccString dcname  == "DontCare"
-    otherwise ->
-      False
-  where
-    tycon = DataCon.dataConTyCon datacon
-    tyname = TyCon.tyConName tycon
-    dcname = DataCon.dataConName datacon
-
 -- | Translates a dataconstructor without arguments to the corresponding
 --   literal.
 dataConToLiteral :: DataCon.DataCon -> FlattenState String
@@ -398,7 +379,7 @@ dataConToLiteral datacon = do
     -- TODO: Do something more robust than string matching
     "Bit"      -> do
       let dcname = DataCon.dataConName datacon
-      let lit = case Name.getOccString dcname of "High" -> "'1'"; "Low" -> "'0'"; "DontCare" -> "'-'"
+      let lit = case Name.getOccString dcname of "High" -> "'1'"; "Low" -> "'0'"
       return lit
     "Bool" -> do
       let dcname = DataCon.dataConName datacon
-- 
2.30.2