X-Git-Url: https://git.stderr.nl/gitweb?a=blobdiff_plain;ds=sidebyside;f=Adders.hs;h=71d38dc4197293febaaca3917998fc8cf94841e2;hb=1e7d79de8b34aca4bf0f63d3822dd0b018356038;hp=f29927ceac3fd6e0804ade47ca5974ccae5ae333;hpb=844555bd28c13cfe1bcb450960008e81928fe2c5;p=matthijs%2Fmaster-project%2Fc%CE%BBash.git

diff --git a/Adders.hs b/Adders.hs
index f29927c..71d38dc 100644
--- a/Adders.hs
+++ b/Adders.hs
@@ -10,6 +10,22 @@ 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)
+
 -- Combinatoric stateless no-carry adder
 -- A -> B -> S
 no_carry_adder :: (Bit, Bit) -> Bit
@@ -26,8 +42,9 @@ 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))
+    x = a `hwxor` b
+    s = x `hwxor` cin
+    c = a `hwand` b `hwor` (cin `hwand` x)
 
 -- Four bit adder
 -- Explicit version