From 4f5817c0327dd4b2aa812808141f9b8ed637bda9 Mon Sep 17 00:00:00 2001
From: Joscha <joscha@plugh.de>
Date: Fri, 8 Nov 2019 18:45:47 +0000
Subject: [PATCH] Fix topBit always returning False

---
 src/Mima/Word.hs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Mima/Word.hs b/src/Mima/Word.hs
index b9a54ea..353c06a 100644
--- a/src/Mima/Word.hs
+++ b/src/Mima/Word.hs
@@ -31,7 +31,7 @@ type SmallValue  = Word16
 type Opcode      = Word4
 
 topBit :: (FiniteBits b) => b -> Bool
-topBit b = testBit b $ finiteBitSize b
+topBit b = testBit b $ finiteBitSize b - 1
 
 bytesToWord :: (Word8, Word8, Word8) -> MimaWord
 bytesToWord (w1, w2, w3) =