diff --git a/opcodes/ChangeLog b/opcodes/ChangeLog
index 4638e150c1e..9367d1c040c 100644
--- a/opcodes/ChangeLog
+++ b/opcodes/ChangeLog
@@ -1,3 +1,9 @@
+2015-08-11  Nick Clifton  <nickc@redhat.com>
+
+	PR 18800
+	* aarch64-tbl.h (aarch64_opcode_table): Fix mask for SIMD EXT
+	instruction.
+
 2015-08-10  Robert Suchanek  <robert.suchanek@imgtec.com>
 
 	* mips-opc.c (mips_builtin_opcodes): Add "sigrie".
diff --git a/opcodes/aarch64-tbl.h b/opcodes/aarch64-tbl.h
index cbb951ba524..86bc029654d 100644
--- a/opcodes/aarch64-tbl.h
+++ b/opcodes/aarch64-tbl.h
@@ -1367,7 +1367,7 @@ struct aarch64_opcode aarch64_opcode_table[] =
   {"sqrdmlah", 0x2f00d000, 0xbf00f400, asimdelem, 0, RDMA, OP3 (Vd, Vn, Em), QL_ELEMENT, F_SIZEQ},
   {"sqrdmlsh", 0x2f00f000, 0xbf00f400, asimdelem, 0, RDMA, OP3 (Vd, Vn, Em), QL_ELEMENT, F_SIZEQ},
   /* AdvSIMD EXT.  */
-  {"ext", 0x2e000000, 0xbfe0c400, asimdext, 0, SIMD, OP4 (Vd, Vn, Vm, IDX), QL_VEXT, F_SIZEQ},
+  {"ext", 0x2e000000, 0xbfe08400, asimdext, 0, SIMD, OP4 (Vd, Vn, Vm, IDX), QL_VEXT, F_SIZEQ},
   /* AdvSIMD modified immediate.  */
   {"movi", 0xf000400, 0xbff89c00, asimdimm, 0, SIMD, OP2 (Vd, SIMD_IMM_SFT), QL_SIMD_IMM_S0W, F_SIZEQ},
   {"orr", 0xf001400, 0xbff89c00, asimdimm, 0, SIMD, OP2 (Vd, SIMD_IMM_SFT), QL_SIMD_IMM_S0W, F_SIZEQ},