4 files changed, 11 insertions, 0 deletions
diff --git a/ABC/Machine/BStack.dcl b/ABC/Machine/BStack.dcl
index 9d938ef..9a0041d 100644
--- a/ABC/Machine/BStack.dcl
+++ b/ABC/Machine/BStack.dcl
@@ -39,3 +39,4 @@ bs_mulI   :: BStack -> BStack
 bs_negI   :: BStack -> BStack
 bs_remI   :: BStack -> BStack
 bs_subI   :: BStack -> BStack
+bs_notB   :: BStack -> BStack
diff --git a/ABC/Machine/BStack.icl b/ABC/Machine/BStack.icl
index a9a2d0e..ab96d60 100644
--- a/ABC/Machine/BStack.icl
+++ b/ABC/Machine/BStack.icl
@@ -113,3 +113,7 @@ bs_remI _               = abortn "bs_remI: no integers"
 bs_subI   :: BStack -> BStack
 bs_subI [Int m:Int n:s] = bs_pushI (m - n) s
 bs_subI _               = abortn "bs_subI: no integers"
+
+bs_notB   :: BStack -> BStack
+bs_notB [Bool b:s] = bs_pushB (not b) s
+bs_notB _          = abortn "bs_notI: no integer"
diff --git a/ABC/Machine/Instructions.dcl b/ABC/Machine/Instructions.dcl
index d5a37f9..2c580e6 100644
--- a/ABC/Machine/Instructions.dcl
+++ b/ABC/Machine/Instructions.dcl
@@ -65,3 +65,5 @@ mulI :: State -> State
 negI :: State -> State
 remI :: State -> State
 subI :: State -> State
+
+notB :: State -> State
diff --git a/ABC/Machine/Instructions.icl b/ABC/Machine/Instructions.icl
index 54e7ebd..37c436d 100644
--- a/ABC/Machine/Instructions.icl
+++ b/ABC/Machine/Instructions.icl
@@ -396,3 +396,7 @@ remI st=:{bstack}
 subI :: State -> State
 subI st=:{bstack}
 	= {st & bstack=bs_subI bstack}
+
+notB :: State -> State
+notB st=:{bstack}
+	= {st & bstack=bs_notB bstack}