diff --git a/stepmania/src/archutils/Win32/arch_setup.h b/stepmania/src/archutils/Win32/arch_setup.h
index 05b8346ee4..e9c9d0ecc9 100644
--- a/stepmania/src/archutils/Win32/arch_setup.h
+++ b/stepmania/src/archutils/Win32/arch_setup.h
@@ -104,7 +104,7 @@ inline uint32_t ArchSwap32( uint32_t n )
 		xchg al, ah
 		ror eax, 16
 		xchg al, ah
-		mov n, eax
+		ret
 	};
 }
 
@@ -117,7 +117,7 @@ inline uint32_t ArchSwap24( uint32_t n )
 		ror eax, 16
 		xchg al, ah
 		ror eax, 8
-		mov n, eax
+		ret
 	};
 }
 
@@ -125,9 +125,10 @@ inline uint16_t ArchSwap16( uint16_t n )
 {
 	__asm
 	{
+		mov eax, 0 /* make sure high 16-bits are zero */
 		mov ax, n
 		xchg al, ah
-		mov n, ax
+		ret
 	};
 }