diff --git a/mach/i86/as/mach3.c b/mach/i86/as/mach3.c
index 535efb8c..005cc82a 100644
--- a/mach/i86/as/mach3.c
+++ b/mach/i86/as/mach3.c
@@ -313,6 +313,7 @@
 0,	NOOP_1,		0157,			"outs",
 0,	NOOP_1,		0157,			"outsw",
 
+0,	ARPLOP,		0143,			"arpl",
 0,	ENTER,		0310,			"enter",
 0,	NOOP_1,		0311,			"leave",
 0,	LEAOP,		0142,			"bound",
diff --git a/mach/i86/as/mach4.c b/mach/i86/as/mach4.c
index e6126bd0..3fd78c78 100644
--- a/mach/i86/as/mach4.c
+++ b/mach/i86/as/mach4.c
@@ -65,6 +65,8 @@ oper	:	NOOP_1
 			}
 	|	LEAOP R16 ',' mem
 			{	emit1($1); ea_2($2<<3);}
+	|	ARPLOP mem ',' R16
+			{	emit1($1); ea_2($4<<3);}
 	|	EXTOP	R16 ',' ea_2
 			{	emit1(0xF); emit1($1);
 				ea_2($2<<3);