From 52d5de13a6c89e7dbc46627888210ddcda1c3e6c Mon Sep 17 00:00:00 2001
From: Matthijs Kooijman <m.kooijman@student.utwente.nl>
Date: Mon, 25 May 2009 11:58:23 +0200
Subject: [PATCH] Update the hardware models a bit.

---
 Adders.hs | 34 +++++++++++++++++++++++++++-------
 Alu.hs    |  4 ++--
 2 files changed, 29 insertions(+), 9 deletions(-)

diff --git a/Adders.hs b/Adders.hs
index f07c8e9..e6676e9 100644
--- a/Adders.hs
+++ b/Adders.hs
@@ -2,7 +2,7 @@ module Adders where
 import Bits
 import qualified Sim
 import Language.Haskell.Syntax
-import Data.TypeLevel
+import qualified Data.TypeLevel as TypeLevel
 import qualified Data.Param.FSVec as FSVec
 
 mainIO f = Sim.simulateIO (Sim.stateless f) ()
@@ -26,10 +26,10 @@ mux2 High (a, b) = b
 wire :: Bit -> Bit
 wire a = a
 
-bus :: (Pos len) => BitVec len -> BitVec len
+bus :: (TypeLevel.Pos len) => BitVec len -> BitVec len
 bus v = v
 
-bus_4 :: BitVec D4 -> BitVec D4
+bus_4 :: BitVec TypeLevel.D4 -> BitVec TypeLevel.D4
 bus_4 v = v
 
 {-
@@ -72,11 +72,31 @@ dff d s = (s', q)
 
 type ShifterState = (Bit, Bit, Bit, Bit)
 shifter :: Bit -> ShifterState -> (ShifterState, Bit)
-shifter a s =
-  (s', o)
+shifter i (a, b, c, d) =
+  (s', d)
   where
-    s' = (a, b, c, d)
-    (b, c, d, o) = s
+    s' = (i, a, b, c)
+
+{-# NOINLINE shifter_en #-}
+shifter_en :: Bit -> Bit-> ShifterState -> (ShifterState, Bit)
+shifter_en High i (a, b, c, d) =
+  (s', d)
+  where
+    s' = (i, a, b, c)
+
+shifter_en Low i s@(a, b, c, d) =
+  (s, d)
+
+-- Two multiplexed shifters
+type ShiftersState = (ShifterState, ShifterState)
+shifters :: Bit -> Bit -> ShiftersState -> (ShiftersState, Bit)
+shifters sel i (sa, sb) =
+  (s', out)
+  where
+    (sa', outa) = shifter_en sel i sa
+    (sb', outb) = shifter_en (hwnot sel) i sb
+    s' = (sa', sb')
+    out = if sel == High then outa else outb
 
 -- Combinatoric stateless no-carry adder
 -- A -> B -> S
diff --git a/Alu.hs b/Alu.hs
index 1797820..5403908 100644
--- a/Alu.hs
+++ b/Alu.hs
@@ -58,8 +58,8 @@ alu :: AluOp -> Word -> Word -> Word
 {-# NOINLINE alu #-}
 --alu High a b = a `hwand` b
 --alu Low a b = a `hwor` b
-alu High a b = a
-alu Low a b = b
+alu High a b = a + b
+alu Low a b = a - b
 
 type ExecState = (RegisterBankState, Word, Word)
 exec :: (RegAddr, Bit, AluOp) -> ExecState -> (ExecState, Word)
-- 
2.30.2