diff --git a/amaranth/sim/_pycoro.py b/amaranth/sim/_pycoro.py
index 63df6ec..503984d 100644
--- a/amaranth/sim/_pycoro.py
+++ b/amaranth/sim/_pycoro.py
@@ -1,13 +1,61 @@
 import inspect
 
+from .._utils import deprecated
 from ..hdl import *
 from ..hdl._ast import Statement, Assign, SignalSet, ValueCastable
-from .core import Tick, Settle, Delay, Passive, Active
 from ._base import BaseProcess, BaseMemoryState
 from ._pyeval import eval_value, eval_assign
 
 
-__all__ = ["PyCoroProcess"]
+__all__ = ["Command", "Settle", "Delay", "Tick", "Passive", "Active", "PyCoroProcess"]
+
+
+class Command:
+    pass
+
+
+class Settle(Command):
+    @deprecated("The `Settle` command is deprecated per RFC 27. Use `add_testbench` to write "
+                "testbenches; in them, an equivalent of `yield Settle()` is performed "
+                "automatically.")
+    def __init__(self):
+        pass
+
+    def __repr__(self):
+        return "(settle)"
+
+
+class Delay(Command):
+    def __init__(self, interval=None):
+        self.interval = None if interval is None else float(interval)
+
+    def __repr__(self):
+        if self.interval is None:
+            return "(delay ε)"
+        else:
+            return f"(delay {self.interval * 1e6:.3}us)"
+
+
+class Tick(Command):
+    def __init__(self, domain="sync"):
+        if not isinstance(domain, (str, ClockDomain)):
+            raise TypeError("Domain must be a string or a ClockDomain instance, not {!r}"
+                            .format(domain))
+        assert domain != "comb"
+        self.domain = domain
+
+    def __repr__(self):
+        return f"(tick {self.domain})"
+
+
+class Passive(Command):
+    def __repr__(self):
+        return "(passive)"
+
+
+class Active(Command):
+    def __repr__(self):
+        return "(active)"
 
 
 class PyCoroProcess(BaseProcess):
diff --git a/amaranth/sim/core.py b/amaranth/sim/core.py
index 936cd5f..f6e05af 100644
--- a/amaranth/sim/core.py
+++ b/amaranth/sim/core.py
@@ -7,59 +7,12 @@ from ..hdl._ir import *
 from ..hdl._ast import Value, ValueLike
 from ..hdl._mem import MemoryData
 from ._base import BaseEngine
+from ._pycoro import Tick, Settle, Delay, Passive, Active
 
 
 __all__ = ["Settle", "Delay", "Tick", "Passive", "Active", "Simulator"]
 
 
-class Command:
-    pass
-
-
-class Settle(Command):
-    @deprecated("The `Settle` command is deprecated per RFC 27. Use `add_testbench` to write "
-                "testbenches; in them, an equivalent of `yield Settle()` is performed "
-                "automatically.")
-    def __init__(self):
-        pass
-
-    def __repr__(self):
-        return "(settle)"
-
-
-class Delay(Command):
-    def __init__(self, interval=None):
-        self.interval = None if interval is None else float(interval)
-
-    def __repr__(self):
-        if self.interval is None:
-            return "(delay ε)"
-        else:
-            return f"(delay {self.interval * 1e6:.3}us)"
-
-
-class Tick(Command):
-    def __init__(self, domain="sync"):
-        if not isinstance(domain, (str, ClockDomain)):
-            raise TypeError("Domain must be a string or a ClockDomain instance, not {!r}"
-                            .format(domain))
-        assert domain != "comb"
-        self.domain = domain
-
-    def __repr__(self):
-        return f"(tick {self.domain})"
-
-
-class Passive(Command):
-    def __repr__(self):
-        return "(passive)"
-
-
-class Active(Command):
-    def __repr__(self):
-        return "(active)"
-
-
 class Simulator:
     def __init__(self, fragment, *, engine="pysim"):
         if isinstance(engine, type) and issubclass(engine, BaseEngine):