diff --git a/src/cmd/6l/l.h b/src/cmd/6l/l.h
index 265a6947e86..ecab867e430 100644
--- a/src/cmd/6l/l.h
+++ b/src/cmd/6l/l.h
@@ -193,7 +193,7 @@ struct	Optab
 	short	as;
 	uchar*	ytab;
 	uchar	prefix;
-	uchar	op[22];
+	uchar	op[23];
 };
 struct	Movtab
 {
diff --git a/src/cmd/6l/optab.c b/src/cmd/6l/optab.c
index c354967b982..46603ad451f 100644
--- a/src/cmd/6l/optab.c
+++ b/src/cmd/6l/optab.c
@@ -913,7 +913,7 @@ Optab optab[] =
 	{ AMOVHLPS,	yxr,	Pm, 0x12 },
 	{ AMOVHPD,	yxmov,	Pe, 0x16,0x17 },
 	{ AMOVHPS,	yxmov,	Pm, 0x16,0x17 },
-	{ AMOVL,	ymovl,	Px, 0x89,0x8b,0x31,0xb8,0xc7,(00),0x6e,0x7e,Pe,0x6e,Pe,0x7e },
+	{ AMOVL,	ymovl,	Px, 0x89,0x8b,0x31,0xb8,0xc7,(00),0x6e,0x7e,Pe,0x6e,Pe,0x7e,0 },
 	{ AMOVLHPS,	yxr,	Pm, 0x16 },
 	{ AMOVLPD,	yxmov,	Pe, 0x12,0x13 },
 	{ AMOVLPS,	yxmov,	Pm, 0x12,0x13 },
@@ -925,7 +925,7 @@ Optab optab[] =
 	{ AMOVNTPD,	yxr_ml,	Pe, 0x2b },
 	{ AMOVNTPS,	yxr_ml,	Pm, 0x2b },
 	{ AMOVNTQ,	ymr_ml,	Pm, 0xe7 },
-	{ AMOVQ,	ymovq,	Pw, 0x89, 0x8b, 0x31, 0xc7,(00), 0xb8, 0xc7,(00), 0x6f, 0x7f, 0x6e, 0x7e, Pf2,0xd6, Pf3,0x7e, Pe,0xd6, Pe,0x6e, Pe,0x7e },
+	{ AMOVQ,	ymovq,	Pw, 0x89, 0x8b, 0x31, 0xc7,(00), 0xb8, 0xc7,(00), 0x6f, 0x7f, 0x6e, 0x7e, Pf2,0xd6, Pf3,0x7e, Pe,0xd6, Pe,0x6e, Pe,0x7e,0 },
 	{ AMOVQOZX,	ymrxr,	Pf3, 0xd6,0x7e },
 	{ AMOVSB,	ynone,	Pb, 0xa4 },
 	{ AMOVSD,	yxmov,	Pf2, 0x10,0x11 },
@@ -935,7 +935,7 @@ Optab optab[] =
 	{ AMOVSW,	ynone,	Pe, 0xa5 },
 	{ AMOVUPD,	yxmov,	Pe, 0x10,0x11 },
 	{ AMOVUPS,	yxmov,	Pm, 0x10,0x11 },
-	{ AMOVW,	ymovw,	Pe, 0x89,0x8b,0x31,0xb8,0xc7,(00) },
+	{ AMOVW,	ymovw,	Pe, 0x89,0x8b,0x31,0xb8,0xc7,(00),0 },
 	{ AMOVWLSX,	yml_rl,	Pm, 0xbf },
 	{ AMOVWLZX,	yml_rl,	Pm, 0xb7 },
 	{ AMOVWQSX,	yml_rl,	Pw, 0x0f,0xbf },
diff --git a/src/cmd/8l/l.h b/src/cmd/8l/l.h
index 2167ccb003b..814aa14582c 100644
--- a/src/cmd/8l/l.h
+++ b/src/cmd/8l/l.h
@@ -175,7 +175,7 @@ struct	Optab
 	short	as;
 	uchar*	ytab;
 	uchar	prefix;
-	uchar	op[12];
+	uchar	op[13];
 };
 
 enum
diff --git a/src/cmd/8l/optab.c b/src/cmd/8l/optab.c
index 78fe45238e7..a4c40e8e379 100644
--- a/src/cmd/8l/optab.c
+++ b/src/cmd/8l/optab.c
@@ -152,6 +152,17 @@ uchar	ymovb[] =
 	Yi32,	Ymb,	Zibo_m,	2,
 	0
 };
+uchar	ymovw[] =
+{
+	Yrl,	Yml,	Zr_m,	1,
+	Yml,	Yrl,	Zm_r,	1,
+	Yi0,	Yrl,	Zclr,	1+2,
+//	Yi0,	Yml,	Zibo_m,	2,	// shorter but slower AND $0,dst
+	Yi32,	Yrl,	Zil_rp,	1,
+	Yi32,	Yml,	Zilo_m,	2,
+	Yiauto,	Yrl,	Zaut_r,	1,
+	0
+};
 uchar	ymovl[] =
 {
 	Yrl,	Yml,	Zr_m,	1,
@@ -162,7 +173,7 @@ uchar	ymovl[] =
 	Yi32,	Yml,	Zilo_m,	2,
 	Yml,	Yxr,	Zm_r_xm,	2,	// XMM MOVD (32 bit)
 	Yxr,	Yml,	Zr_m_xm,	2,	// XMM MOVD (32 bit)
-	Yiauto,	Yrl,	Zaut_r,	2,
+	Yiauto,	Yrl,	Zaut_r,	1,
 	0
 };
 uchar	ymovq[] =
@@ -592,8 +603,8 @@ Optab optab[] =
 	{ ALSLL,	yml_rl,	Pm, 0x03  },
 	{ ALSLW,	yml_rl,	Pq, 0x03  },
 	{ AMOVB,	ymovb,	Pb, 0x88,0x8a,0xb0,0xc6,(00) },
-	{ AMOVL,	ymovl,	Px, 0x89,0x8b,0x31,0x83,(04),0xb8,0xc7,(00),Pe,0x6e,Pe,0x7e },
-	{ AMOVW,	ymovl,	Pe, 0x89,0x8b,0x31,0x83,(04),0xb8,0xc7,(00) },
+	{ AMOVL,	ymovl,	Px, 0x89,0x8b,0x31,0x83,(04),0xb8,0xc7,(00),Pe,0x6e,Pe,0x7e,0 },
+	{ AMOVW,	ymovw,	Pe, 0x89,0x8b,0x31,0x83,(04),0xb8,0xc7,(00),0 },
 	{ AMOVQ,	ymovq,	Pf3, 0x7e },
 	{ AMOVBLSX,	ymb_rl,	Pm, 0xbe },
 	{ AMOVBLZX,	ymb_rl,	Pm, 0xb6 },