os: rework kernel architecture

Rework the code structure and architecture of the kernel by separating
platform-dependent and platform-independent code more cleanly. As of
this patchset, full feature parity has not been achieved. Nonetheless, a
sufficient subset of functionality has been ported to the new
architecture to demonstrate the feasibility of the new structure.

1 files changed, 35 insertions, 0 deletions

diff --git a/arch/x86_64/pre/src/user/main.cpp b/arch/x86_64/pre/src/user/main.cpp
new file mode 100644
index 0000000..8b07e4a
--- /dev/null
+++ b/arch/x86_64/pre/src/user/main.cpp
@@ -0,0 +1,35 @@
+#include "arch/user/main.hpp"
+
+#include "arch/context_switching/syscall/main.hpp"
+#include "arch/memory/heap/global_heap_allocator.hpp"
+
+#include <algorithm>
+#include <array>
+#include <atomic>
+#include <ranges>
+
+namespace teachos::arch::user
+{
+  auto main() -> void
+  {
+    constexpr char syscall_message[] = "Successfully entered user mode and wrote to VGA buffer via syscall!";
+    context_switching::syscall::syscall(context_switching::syscall::type::WRITE,
+                                        {reinterpret_cast<uint64_t>(&syscall_message)});
+
+    // Test C++ standard library
+    std::array<std::atomic<uint8_t>, 4> array_test = {std::atomic<uint8_t>{5}, std::atomic<uint8_t>{10},
+                                                      std::atomic<uint8_t>{15}, std::atomic<uint8_t>{20}};
+    std::ranges::for_each(array_test, [](auto & item) {
+      auto value = item.load();
+      uint8_t max_value = std::max(value, uint8_t{10});
+      item.exchange(max_value + 2);
+    });
+
+    auto address = new uint64_t{10U};
+    (void)address;
+
+    for (;;)
+    {
+    }
+  }
+}  // namespace teachos::arch::user