diff --git a/opcodes/ChangeLog b/opcodes/ChangeLog
index 14a1407481..4f27092152 100644
--- a/opcodes/ChangeLog
+++ b/opcodes/ChangeLog
@@ -1,3 +1,10 @@
+2019-11-05  Jan Beulich  <jbeulich@suse.com>
+
+	* i386-dis.c (PREFIX_0F01_REG_7_MOD_3_RM_2,
+	PREFIX_0F01_REG_7_MOD_3_RM_3): New.
+	(prefix_table): Add respective entries.
+	(rm_table): Link to those entries.
+
 2019-11-05  Jan Beulich  <jbeulich@suse.com>
 
 	* i386-dis.c (REG_0F1C_MOD_0): Rename to ...
diff --git a/opcodes/i386-dis.c b/opcodes/i386-dis.c
index d1d8b55af3..11a9e33fbe 100644
--- a/opcodes/i386-dis.c
+++ b/opcodes/i386-dis.c
@@ -964,6 +964,8 @@ enum
   PREFIX_0F01_REG_5_MOD_0,
   PREFIX_0F01_REG_5_MOD_3_RM_0,
   PREFIX_0F01_REG_5_MOD_3_RM_2,
+  PREFIX_0F01_REG_7_MOD_3_RM_2,
+  PREFIX_0F01_REG_7_MOD_3_RM_3,
   PREFIX_0F09,
   PREFIX_0F10,
   PREFIX_0F11,
@@ -3643,6 +3645,16 @@ static const struct dis386 prefix_table[][4] = {
     { "saveprevssp",	{ Skip_MODRM }, PREFIX_OPCODE },
   },
 
+  /* PREFIX_0F01_REG_7_MOD_3_RM_2 */
+  {
+    { "monitorx",	{ { OP_Monitor, 0 } }, 0  },
+  },
+
+  /* PREFIX_0F01_REG_7_MOD_3_RM_3 */
+  {
+    { "mwaitx",		{ { OP_Mwaitx,  0 } }, 0  },
+  },
+
   /* PREFIX_0F09 */
   {
     { "wbinvd",   { XX }, 0 },
@@ -11016,8 +11028,8 @@ static const struct dis386 rm_table[][8] = {
     /* RM_0F01_REG_7_MOD_3 */
     { "swapgs",		{ Skip_MODRM }, 0  },
     { "rdtscp",		{ Skip_MODRM }, 0  },
-    { "monitorx",	{ { OP_Monitor, 0 } }, 0  },
-    { "mwaitx",		{ { OP_Mwaitx,  0 } }, 0  },
+    { PREFIX_TABLE (PREFIX_0F01_REG_7_MOD_3_RM_2) },
+    { PREFIX_TABLE (PREFIX_0F01_REG_7_MOD_3_RM_3) },
     { "clzero",		{ Skip_MODRM }, 0  },
   },
   {