X-Git-Url: https://git.stderr.nl/gitweb?a=blobdiff_plain;f=Adders.hs;h=10590fa7c765736ced0e4cf166160687c4ff2fd1;hb=709b1c003317e745eecf745c3659afa75191a36c;hp=f29927ceac3fd6e0804ade47ca5974ccae5ae333;hpb=844555bd28c13cfe1bcb450960008e81928fe2c5;p=matthijs%2Fmaster-project%2Fc%CE%BBash.git

diff --git a/Adders.hs b/Adders.hs
index f29927c..10590fa 100644
--- a/Adders.hs
+++ b/Adders.hs
@@ -1,8 +1,13 @@
 module Adders where
 import Bits
+import qualified Sim
 import Language.Haskell.Syntax
 
-main = do show_add exp_adder; show_add rec_adder;
+mainIO f = Sim.simulateIO (Sim.stateless f) ()
+
+-- This function is from Sim.hs, but we redefine it here so it can get inlined
+-- by default.
+stateless f = \i s -> (s, f i)
 
 show_add f = do print ("Sum:   " ++ (displaysigs s)); print ("Carry: " ++ (displaysig c))
   where
@@ -10,6 +15,29 @@ show_add f = do print ("Sum:   " ++ (displaysigs s)); print ("Carry: " ++ (displ
     b = [Low, Low, Low, High]
     (s, c) = f (a, b)
 
+-- Not really an adder, but this is nice minimal hardware description
+wire :: Bit -> Bit
+wire a = a
+
+-- Not really an adder either, but a slightly more complex example
+inv :: Bit -> Bit
+inv a = hwnot a
+
+-- Not really an adder either, but a slightly more complex example
+invinv :: Bit -> Bit
+invinv a = hwnot (hwnot a)
+
+-- Not really an adder either, but a slightly more complex example
+dup :: Bit -> (Bit, Bit)
+dup a = (a, a)
+
+-- Not really an adder either, but a simple stateful example (D-flipflop)
+dff :: Bit -> Bit -> (Bit, Bit)
+dff d s = (s', q)
+  where
+    q = s
+    s' = d
+
 -- Combinatoric stateless no-carry adder
 -- A -> B -> S
 no_carry_adder :: (Bit, Bit) -> Bit
@@ -26,8 +54,11 @@ half_adder (a, b) =
 full_adder :: (Bit, Bit, Bit) -> (Bit, Bit)
 full_adder (a, b, cin) = (s, c)
   where
-    s = a `hwxor` b `hwxor` cin
-    c = a `hwand` b `hwor` (cin `hwand` (a `hwxor` b))
+    (s1, c1) = half_adder(a, b)
+    (s, c2)  = half_adder(s1, cin)
+    c        = c1 `hwor` c2
+
+sfull_adder = stateless full_adder
 
 -- Four bit adder
 -- Explicit version