diff --git a/erlang/apps/sim/src/sim_core.erl b/erlang/apps/sim/src/sim_core.erl
index ed9171c..d241cda 100644
--- a/erlang/apps/sim/src/sim_core.erl
+++ b/erlang/apps/sim/src/sim_core.erl
@@ -228,6 +228,7 @@ dispatch(Core, Mem, IR, EA) ->
     8#201 -> sim_moves:handle_MOVEI(Core, Mem, IR, EA);
     8#202 -> sim_moves:handle_MOVEM(Core, Mem, IR, EA);
     8#203 -> sim_moves:handle_MOVES(Core, Mem, IR, EA);
+    8#204 -> sim_moves:handle_MOVS(Core, Mem, IR, EA);
     8#250 -> sim_moves:handle_EXCH(Core, Mem, IR, EA);
     _ ->
       PC = (Core#core.pc_section bsl 18) bor Core#core.pc_offset,
diff --git a/erlang/apps/sim/src/sim_moves.erl b/erlang/apps/sim/src/sim_moves.erl
index 070a475..f52bd47 100644
--- a/erlang/apps/sim/src/sim_moves.erl
+++ b/erlang/apps/sim/src/sim_moves.erl
@@ -29,6 +29,7 @@
         , handle_MOVEI/4
         , handle_MOVEM/4
         , handle_MOVES/4
+        , handle_MOVS/4
         ]).
 
 -include("sim_core.hrl").
@@ -115,6 +116,21 @@ handle_MOVES(Core, Mem, AC, EA, Word) ->
                           fun(Core1, Mem1) -> handle_MOVES(Core1, Mem1, AC, EA, Word) end)
   end.
 
+%% MOVS - Move Swapped
+
+-spec handle_MOVS(#core{}, sim_mem:mem(), IR :: word(), #ea{})
+      -> {#core{}, sim_mem:mem(), {ok, integer()} | {error, {module(), term()}}}.
+handle_MOVS(Core, Mem, IR, EA) ->
+  case sim_core:c(Core, Mem, EA) of
+    {ok, CE} ->
+      Swapped = swap_halves(CE),
+      AC = IR band 8#17,
+      sim_core:next_pc(sim_core:set_ac(Core, AC, Swapped), Mem);
+    {error, Reason} ->
+      sim_core:page_fault(Core, Mem, ea_address(EA), read, Reason,
+                          fun(Core1, Mem1) -> handle_MOVS(Core1, Mem1, IR, EA) end)
+  end.
+
 %% Miscellaneous ===============================================================
 
 ea_address(#ea{section = Section, offset = Offset}) ->
@@ -122,3 +138,7 @@ ea_address(#ea{section = Section, offset = Offset}) ->
 
 set_non_zero_ac(Core, _AC = 0, _Word) -> Core;
 set_non_zero_ac(Core, AC, Word) -> sim_core:set_ac(Core, AC, Word).
+
+swap_halves(Word) ->
+  Low18Mask = ((1 bsl 18) - 1),
+  ((Word band Low18Mask) bsl 18) bor ((Word bsr 18) band Low18Mask).
diff --git a/erlang/apps/sim/test/sim_moves_tests.erl b/erlang/apps/sim/test/sim_moves_tests.erl
index b28025a..30d239f 100644
--- a/erlang/apps/sim/test/sim_moves_tests.erl
+++ b/erlang/apps/sim/test/sim_moves_tests.erl
@@ -47,6 +47,7 @@
 -define(OP_MOVEI, 8#201).
 -define(OP_MOVEM, 8#202).
 -define(OP_MOVES, 8#203).
+-define(OP_MOVS, 8#204).
 -define(OP_EXCH, 8#250).
 
 %% 2.1.1 Exchange Instruction ==================================================
@@ -133,6 +134,16 @@ moves_noac_test() ->
          , {#ea{section = 1, offset = 0, islocal = false}, 8#27} % AC0 = 27
          ]).
 
+movs_test() ->
+  Prog =
+    [ {1, 8#100, ?INSN(?OP_MOVS, 1, 0, 0, 8#150)}   % 1,,100/ MOVS 1,150
+    , {1, 8#101, ?INSN_INVALID}                     % 1,,101/ <invalid>
+    , {1, 8#150, ?COMMA2(8#27, 8#42)}               % 1,,150/ 27,,42
+    ],
+  expect(Prog, [], {1, 8#101}, ?DEFAULT_FLAGS,
+         [ {#ea{section = 1, offset = 1, islocal = false}, ?COMMA2(8#42, 8#27)} % AC1 = 42,,27
+         ]).
+
 %% Common code to run short sequences ==========================================
 
 expect(Prog, ACs, ExpectedPC, ExpectedFlags, ExpectedEs) ->