From 64bf7fcf58ced023be1701ed4508e38f746d40b8 Mon Sep 17 00:00:00 2001
From: Felix Morgner <felix.morgner@ost.ch>
Date: Mon, 16 Mar 2026 08:34:13 +0100
Subject: kernel/memory: implement basic free-list heap

---
 kernel/src/memory.cpp | 55 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 55 insertions(+)
 create mode 100644 kernel/src/memory.cpp

(limited to 'kernel/src/memory.cpp')

diff --git a/kernel/src/memory.cpp b/kernel/src/memory.cpp
new file mode 100644
index 0000000..14bedf1
--- /dev/null
+++ b/kernel/src/memory.cpp
@@ -0,0 +1,55 @@
+#include "kernel/memory.hpp"
+
+#include "kapi/memory.hpp"
+#include "kapi/system.hpp"
+
+#include "kernel/memory/free_list_allocator.hpp"
+#include "kernel/memory/heap_allocator.hpp"
+
+#include <atomic>
+#include <cstddef>
+#include <new>
+#include <optional>
+
+namespace kernel::memory
+{
+
+  namespace
+  {
+    struct null_allocator : heap_allocator
+    {
+      null_allocator static instance;
+
+      [[nodiscard]] auto allocate(std::size_t, std::align_val_t) noexcept -> void * override
+      {
+        return nullptr;
+      }
+
+      auto deallocate(void *) noexcept -> void override {}
+    };
+
+    constinit null_allocator null_allocator::instance{};
+
+    auto constinit active_heap_allocator = std::optional<heap_allocator *>{&null_allocator::instance};
+    auto constinit basic_allocator = std::optional<free_list_allocator>{};
+  }  // namespace
+
+  auto get_heap_allocator() -> heap_allocator &
+  {
+    return *active_heap_allocator.value();
+  }
+
+  auto init_heap(kapi::memory::linear_address base) -> void
+  {
+    auto static constinit is_initialized = std::atomic_flag{};
+
+    if (is_initialized.test_and_set())
+    {
+      kapi::system::panic("[OS] The heap has already been initialized.");
+    }
+
+    auto & instance = basic_allocator.emplace(base);
+    active_heap_allocator = &instance;
+  }
+
+}  // namespace kernel::memory
\ No newline at end of file
-- 
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