diff --git a/erlang/apps/sim/src/sim_boolean.erl b/erlang/apps/sim/src/sim_boolean.erl
index fbb41b6..1314474 100644
--- a/erlang/apps/sim/src/sim_boolean.erl
+++ b/erlang/apps/sim/src/sim_boolean.erl
@@ -71,6 +71,7 @@
         , handle_SETMI/4
         , handle_SETMM/4
         , handle_SETO/4
+        , handle_SETOB/4
         , handle_SETOM/4
         , handle_SETZ/4
         , handle_SETZB/4
@@ -778,6 +779,13 @@ handle_SETOM(Core, Mem, _IR, EA) ->
   Word = (1 bsl 36) - 1,
   handle_ANDM_1(Core, Mem, EA, Word).
 
+-spec handle_SETOB(#core{}, sim_mem:mem(), IR :: word(), #ea{})
+      -> {#core{}, sim_mem:mem(), {ok, integer()} | {error, {module(), term()}}}.
+handle_SETOB(Core, Mem, IR, EA) ->
+  AC = IR band 8#17,
+  Word = (1 bsl 36) - 1,
+  handle_ANDB(Core, Mem, AC, EA, Word).
+
 %% 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 a4efb01..490eb6f 100644
--- a/erlang/apps/sim/src/sim_core.erl
+++ b/erlang/apps/sim/src/sim_core.erl
@@ -316,6 +316,7 @@ dispatch(Core, Mem, IR, EA) ->
     8#474 -> sim_boolean:handle_SETO(Core, Mem, IR, EA);
     8#475 -> sim_boolean:handle_SETO(Core, Mem, IR, EA); % SETOI = SETO
     8#476 -> sim_boolean:handle_SETOM(Core, Mem, IR, EA);
+    8#477 -> sim_boolean:handle_SETOB(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 e3b1946..1db9bb0 100644
--- a/erlang/apps/sim/test/sim_boolean_tests.erl
+++ b/erlang/apps/sim/test/sim_boolean_tests.erl
@@ -107,6 +107,7 @@
 -define(OP_SETO, 8#474).
 -define(OP_SETOI, 8#475).
 -define(OP_SETOM, 8#476).
+-define(OP_SETOB, 8#477).
 
 %% 2.4 Boolean Functions =======================================================
 
@@ -852,6 +853,17 @@ setom_test() ->
          [ {#ea{section = 1, offset = 8#200, islocal = false}, ?COMMA2(-1, -1)} % C(1,,200) = -1,,-1
          ]).
 
+setob_test() ->
+  Prog =
+    [ {1, 8#100, ?INSN(?OP_SETOB, 1, 0, 0, 8#200)} % 1,,100/ SETOB 1,200
+    , {1, 8#101, ?INSN_INVALID}                    % 1,,101/ <invalid>
+    , {1, 8#200, 0}                                % 1,,200/ 0
+    ],
+  expect(Prog, [], {1, 8#101}, ?DEFAULT_FLAGS,
+         [ {#ea{section = 1, offset = 8#200, islocal = false}, ?COMMA2(-1, -1)} % C(1,,200) = -1,,-1
+         , {#ea{section = 1, offset = 1, islocal = false}, ?COMMA2(-1, -1)} % AC1 = -1,,-1
+         ]).
+
 %% Common code to run short sequences ==========================================
 
 expect(Prog, ACs, ExpectedPC, ExpectedFlags, ExpectedEs) ->