diff --git a/erlang/apps/sim/src/sim_boolean.erl b/erlang/apps/sim/src/sim_boolean.erl
index b19d4f0..5cc49c1 100644
--- a/erlang/apps/sim/src/sim_boolean.erl
+++ b/erlang/apps/sim/src/sim_boolean.erl
@@ -49,6 +49,7 @@
         , handle_IORI/4
         , handle_IORM/4
         , handle_ORCA/4
+        , handle_ORCAI/4
         , handle_SETCA/4
         , handle_SETCAB/4
         , handle_SETCAM/4
@@ -559,6 +560,14 @@ handle_ORCA(Core, Mem, IR, EA) ->
                           fun(Core1, Mem1) -> handle_ORCA(Core1, Mem1, IR, EA) end)
   end.
 
+-spec handle_ORCAI(#core{}, sim_mem:mem(), IR :: word(), #ea{})
+      -> {#core{}, sim_mem:mem(), {ok, integer()} | {error, {module(), term()}}}.
+handle_ORCAI(Core, Mem, IR, EA) ->
+  AC = IR band 8#17,
+  CA = sim_core:get_ac(Core, AC),
+  Word = (EA#ea.offset bor bnot CA) band ((1 bsl 36) - 1),
+  sim_core:next_pc(sim_core:set_ac(Core, AC, Word), Mem).
+
 %% Miscellaneous ===============================================================
 
 ea_address(#ea{section = Section, offset = Offset}) ->
diff --git a/erlang/apps/sim/src/sim_core.erl b/erlang/apps/sim/src/sim_core.erl
index 39fc875..384438c 100644
--- a/erlang/apps/sim/src/sim_core.erl
+++ b/erlang/apps/sim/src/sim_core.erl
@@ -298,6 +298,7 @@ dispatch(Core, Mem, IR, EA) ->
     8#452 -> sim_boolean:handle_SETCAM(Core, Mem, IR, EA);
     8#453 -> sim_boolean:handle_SETCAB(Core, Mem, IR, EA);
     8#454 -> sim_boolean:handle_ORCA(Core, Mem, IR, EA);
+    8#455 -> sim_boolean:handle_ORCAI(Core, Mem, IR, EA);
     _ ->
       PC = (Core#core.pc_section bsl 18) bor Core#core.pc_offset,
       {Core, Mem, {error, {?MODULE, {dispatch, PC, IR, EA}}}}
diff --git a/erlang/apps/sim/test/sim_boolean_tests.erl b/erlang/apps/sim/test/sim_boolean_tests.erl
index 075dff8..c611f6c 100644
--- a/erlang/apps/sim/test/sim_boolean_tests.erl
+++ b/erlang/apps/sim/test/sim_boolean_tests.erl
@@ -89,6 +89,7 @@
 -define(OP_SETCAM, 8#452).
 -define(OP_SETCAB, 8#453).
 -define(OP_ORCA, 8#454).
+-define(OP_ORCAI, 8#455).
 
 %% 2.4 Boolean Functions =======================================================
 
@@ -637,6 +638,16 @@ orca_test() ->
          [ {#ea{section = 1, offset = 1, islocal = false}, ?COMMA2(-1, 8#373737)} % AC1 = -1,,373737
          ]).
 
+orcai_test() ->
+  Prog =
+    [ {1, 8#100, ?INSN(?OP_MOVEI, 1, 0, 0, 8#707070)}  % 1,,100/ MOVEI 1,707070
+    , {1, 8#101, ?INSN(?OP_ORCAI, 1, 0, 0, 8#303030)}  % 1,,101/ ORCAI 1,303030
+    , {1, 8#102, ?INSN_INVALID}                        % 1,,102/ <invalid>
+    ],
+  expect(Prog, [], {1, 8#102}, ?DEFAULT_FLAGS,
+         [ {#ea{section = 1, offset = 1, islocal = false}, ?COMMA2(-1, 8#373737)} % AC1 = -1,,373737
+         ]).
+
 %% Common code to run short sequences ==========================================
 
 expect(Prog, ACs, ExpectedPC, ExpectedFlags, ExpectedEs) ->