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.

4 files changed, 85 insertions, 0 deletions

diff --git a/libs/kstd/src/bits/os.cpp b/libs/kstd/src/bits/os.cpp
new file mode 100644
index 0000000..e6edbfd
--- /dev/null
+++ b/libs/kstd/src/bits/os.cpp
@@ -0,0 +1,10 @@
+#include "kstd/bits/os.hpp"
+
+namespace kstd::os
+{
+  [[gnu::weak, noreturn]]
+  auto abort() -> void
+  {
+    os::panic("Abort called.");
+  }
+}  // namespace kstd::os
\ No newline at end of file
diff --git a/libs/kstd/src/libc/stdlib.cpp b/libs/kstd/src/libc/stdlib.cpp
new file mode 100644
index 0000000..a0f062a
--- /dev/null
+++ b/libs/kstd/src/libc/stdlib.cpp
@@ -0,0 +1,19 @@
+#include "kstd/bits/os.hpp"
+
+namespace kstd::libc
+{
+
+  extern "C"
+  {
+    [[noreturn]] auto abort() -> void
+    {
+      kstd::os::abort();
+    }
+
+    [[noreturn, gnu::weak]] auto free(void *) -> void
+    {
+      kstd::os::panic("Tried to call free.");
+    }
+  }
+
+}  // namespace kstd::libc
\ No newline at end of file
diff --git a/libs/kstd/src/libc/string.cpp b/libs/kstd/src/libc/string.cpp
new file mode 100644
index 0000000..319f6fd
--- /dev/null
+++ b/libs/kstd/src/libc/string.cpp
@@ -0,0 +1,32 @@
+#include <algorithm>
+#include <bit>
+#include <cstddef>
+#include <iterator>
+#include <span>
+
+namespace kstd::libc
+{
+
+  extern "C"
+  {
+    auto strlen(char const * string) -> std::size_t
+    {
+      return std::distance(string, std::ranges::find(string, nullptr, '\0'));
+    }
+
+    auto memcmp(void const * lhs, void const * rhs, std::size_t size) -> std::size_t
+    {
+      auto left_span = std::span{static_cast<std::byte const *>(lhs), size};
+      auto right_span = std::span{static_cast<std::byte const *>(rhs), size};
+      auto mismatched = std::ranges::mismatch(left_span, right_span);
+
+      if (mismatched.in1 == left_span.end())
+      {
+        return 0;
+      }
+
+      return std::bit_cast<char>(*mismatched.in1) - std::bit_cast<char>(*mismatched.in2);
+    }
+  }
+
+}  // namespace kstd::libc
\ No newline at end of file
diff --git a/libs/kstd/src/mutex.cpp b/libs/kstd/src/mutex.cpp
new file mode 100644
index 0000000..5a26154
--- /dev/null
+++ b/libs/kstd/src/mutex.cpp
@@ -0,0 +1,24 @@
+#include "kstd/mutex"
+
+#include <atomic>
+
+namespace kstd
+{
+  auto mutex::lock() -> void
+  {
+    while (!try_lock())
+    {
+      asm volatile("nop");
+    }
+  }
+
+  auto mutex::try_lock() -> bool
+  {
+    return !locked.exchange(true, std::memory_order_acquire);
+  }
+
+  auto mutex::unlock() -> void
+  {
+    locked.store(false, std::memory_order_release);
+  }
+}  // namespace kstd