diff --git a/service/ptos/head/arch/amd64/prim.h b/service/ptos/head/arch/amd64/prim.h
new file mode 100644
index 0000000..73743ff
--- /dev/null
+++ b/service/ptos/head/arch/amd64/prim.h
@@ -0,0 +1,43 @@
+/*
+ * Copyright (c) 2026, Chloe M.
+ * Provided under the BSD-3 clause.
+ *
+ * Description: Processor primitives
+ * Author:      Chloe M.
+ */
+
+#ifndef _MACHINE_PRIM_H_
+#define _MACHINE_PRIM_H_ 1
+
+#include <ptdef.h>
+
+#define MdCpuSuspend()  ASMV("hlt")
+#define MdCpuSpinWait() ASMV("pause")
+
+/*
+ * Atomic swap operation
+ *
+ * @Ptr: Location to swap with @Value
+ * @Value: Value to swap to @Ptr
+ */
+ALWAYS_INLINE static inline UQUAD
+MdCpuAswap(UUQUAD *Ptr, UQUAD Value)
+{
+    UQUAD RetVal;
+
+    if (Ptr == NULL) {
+        return 0;
+    }
+
+    RetVal = *(volatile UQUAD *)Ptr;
+    ASMV(
+        "xchg %0, %1\n"
+        : "+m" (*Ptr), "+r" (Value)
+        :
+        : "memory"
+    );
+
+    return RetVal;
+}
+
+#endif  /* !_MACHINE_PRIM_H_ */
diff --git a/service/ptos/head/hal/prim.h b/service/ptos/head/hal/prim.h
new file mode 100644
index 0000000..c217571
--- /dev/null
+++ b/service/ptos/head/hal/prim.h
@@ -0,0 +1,47 @@
+/*
+ * Copyright (c) 2026, Chloe M.
+ * Provided under the BSD-3 clause.
+ *
+ * Description: Processor primitives
+ * Author:      Chloe M.
+ */
+
+#ifndef _HAL_PRIM_H_
+#define _HAL_PRIM_H_ 1
+
+#include <machine/prim.h>
+#include <ptdef.h>
+
+/*
+ * Suspend the current processor until the next
+ * interrupt.
+ */
+ALWAYS_INLINE static inline VOID
+HalCpuSuspend(VOID)
+{
+    MdCpuSuspend();
+}
+
+/*
+ * Hint to the processor core that it is in a spin
+ * loop.
+ */
+ALWAYS_INLINE static inline VOID
+HalCpuSpinWait(VOID)
+{
+    MdCpuSpinWait();
+}
+
+/*
+ * Perform an atomic swap operation
+ *
+ * @Ptr:   Location to swap with @Value
+ * @Value: Value to swap with data at @Ptr
+ */
+ALWAYS_INLINE static inline VOID
+HalCpuAswap(UQUAD *Ptr, UQUAD Value)
+{
+    MdCpuAswap(Ptr, Value);
+}
+
+#endif  /* !_HAL_PRIM_H_ */