2 files changed, 40 insertions, 10 deletions

diff --git a/engines/dreamweb/dreamweb.cpp b/engines/dreamweb/dreamweb.cpp
index f2ee6a6268..feec93f8f5 100644
--- a/engines/dreamweb/dreamweb.cpp
+++ b/engines/dreamweb/dreamweb.cpp
@@ -413,7 +413,7 @@ void mode640x480(Context &context) {
 }
 
 void showgroup(Context &context) {
-	warning("vsync: STUB");
+	warning("showgroup: STUB");
 }
 
 void fadedos(Context &context) {
@@ -426,7 +426,7 @@ void doshake(Context &context) {
 
 void vsync(Context &context) {
 	//engine()->waitForVSync();
-	warning("vsync: STUB");
+	//warning("vsync: STUB"); //fixme: loop
 }
 
 void setmode(Context &context) {
diff --git a/engines/dreamweb/runtime.h b/engines/dreamweb/runtime.h
index af484fe19c..b69bd15d52 100644
--- a/engines/dreamweb/runtime.h
+++ b/engines/dreamweb/runtime.h
@@ -245,14 +245,16 @@ public:
 	}
 
 	inline void _add(uint8 &dst, uint8 src) {
-		flags._c = (unsigned(dst) + src) >= 0x100;
-		dst += src;
+		unsigned r = (unsigned)dst + src;
+		flags._c = r >= 0x100;
+		dst = r;
 		flags.update(dst);
 	}
 
 	inline void _add(uint16 &dst, uint16 src) {
-		flags._c = (unsigned(dst) + src) >= 0x10000;
-		dst += src;
+		unsigned r = (unsigned)dst + src;
+		flags._c = r >= 0x10000;
+		dst = r;
 		flags.update(dst);
 	}
 
@@ -304,10 +306,38 @@ public:
 		flags.update(dst);
 	}
 
-	inline void _shr(uint8 &dst, uint8 src) {}
-	inline void _shr(uint16 &dst, uint8 src) {}
-	inline void _shl(uint8 &dst, uint8 src) {}
-	inline void _shl(uint16 &dst, uint8 src) {}
+	inline void _shr(uint8 &dst, uint8 src) {
+		if (src > 0 && src < 32) {
+			dst >>= (src - 1);
+			flags._c = dst & 1;
+			dst >>= 1;
+		}
+		flags.update(dst);
+	}
+	inline void _shr(uint16 &dst, uint8 src) {
+		if (src > 0 && src < 32) {
+			dst >>= (src - 1);
+			flags._c = dst & 1;
+			dst >>= 1;
+		}
+		flags.update(dst);
+	}
+	inline void _shl(uint8 &dst, uint8 src) {
+		if (src > 0 && src < 32) {
+			dst <<= (src - 1);
+			flags._c = dst & 0x80;
+			dst <<= 1;
+		}
+		flags.update(dst);
+	}
+	inline void _shl(uint16 &dst, uint8 src) {
+		if (src > 0 && src < 32) {
+			dst <<= (src - 1);
+			flags._c = dst & 0x8000;
+			dst <<= 1;
+		}
+		flags.update(dst);
+	}
 
 	inline void _mul(uint8 src) {
 		unsigned r = unsigned(al) * src;