diff --git a/mach/m68k2/as/mach4.c b/mach/m68k2/as/mach4.c
index 1085b8cf7..a8c0c36ff 100644
--- a/mach/m68k2/as/mach4.c
+++ b/mach/m68k2/as/mach4.c
@@ -32,8 +32,11 @@ operation
 			}
 	|	BITOP ea_ea
 			{	bitop($1);}
-	|	OP_EA_D ea ',' DREG
-			{	emit2($1 | mrg_2 | $4<<9);
+	|	OP_EA_D sizedef ea ',' DREG
+			{	if ($2 != SIZE_W) {
+					serror("illegal size");
+				}
+				emit2($1 | mrg_2 | $5<<9);
 				ea_2(SIZE_W, DTA);
 			}
 	|	LEA ea ',' AREG