Allow syntax cpl a

test/asm/destination-a.asm

@@ -0,0 +1,21 @@
+SECTION "destination optional", ROM0[0]
+
+MACRO both
+	REDEF op EQUS "\1"
+	SHIFT
+	{op} \#
+	if _NARG
+		{op} a, \#
+	else
+		{op} a
+	endc
+ENDM
+
+	both cpl
+	both add, b
+	both adc, 42
+	both sub, 69
+	both sbc, c
+	both and, d
+	both or, %1010
+	both xor, $80