Better generated code

1 files changed, 12 insertions, 7 deletions

diff --git a/Compiler.hs b/Compiler.hs
index f02a50a..23ce5d3 100644
--- a/Compiler.hs
+++ b/Compiler.hs
@@ -64,12 +64,18 @@ compileIns (ICopy _ _ 0) = return ()
 compileIns (ICopy from to m) = do
     emit $ "mov al, [" ++ cursorOffset from ++ "]"
     case m of
-        1 -> return ()
-        _ | Just p <- isTwoPower m -> emit $ "shl al, " ++ show p
+        1 -> emit $ "add [" ++ cursorOffset to ++ "], al"
+        -1 -> emit $ "sub [" ++ cursorOffset to ++ "], al"
+        _ | Just p <- isTwoPower m -> do
+                emit $ "shl al, " ++ show p
+                emit $ "add [" ++ cursorOffset to ++ "], al"
+          | Just p <- isTwoPower (-m) -> do
+                emit $ "shl al, " ++ show p
+                emit $ "sub [" ++ cursorOffset to ++ "], al"
           | otherwise -> do
-                             emit $ "mov cl, " ++ show m
-                             emit "mul byte cl"
-    emit $ "add [" ++ cursorOffset to ++ "], al"
+                emit $ "mov cl, " ++ show m
+                emit "mul byte cl"
+                emit $ "add [" ++ cursorOffset to ++ "], al"
 compileIns (ISlide off) = emit $ "add " ++ cursorReg ++ ", " ++ show off
 compileIns (ILoop inss off) = do
     loopid <- genId
@@ -84,8 +90,7 @@ compileIns (IInput off) = do
     emit $ generateCall "getchar"
     emit $ "mov [" ++ cursorOffset off ++ "], al"
 compileIns (IOutput off) = do
-    emit "xor edi, edi"
-    emit $ "mov dil, [" ++ cursorOffset off ++ "]"
+    emit $ "movzx edi, byte [" ++ cursorOffset off ++ "]"
     emit $ generateCall "putchar"
 compileIns IStart = return ()