From bd585306e31889ee4fce60abb79bc3b3a58e2b84 Mon Sep 17 00:00:00 2001
From: Felix Morgner <felix.morgner@ost.ch>
Date: Mon, 6 Apr 2026 13:11:15 +0200
Subject: kapi: add basic ACPI support

---
 libs/kstd/include/kstd/units                       |  7 +++-
 .../multiboot2/constants/information_id.hpp        |  8 ++--
 libs/multiboot2/include/multiboot2/information.hpp | 43 +++++++++++++++++++++-
 .../include/multiboot2/information/data.hpp        | 12 +++++-
 4 files changed, 63 insertions(+), 7 deletions(-)

(limited to 'libs')

diff --git a/libs/kstd/include/kstd/units b/libs/kstd/include/kstd/units
index f6dcdb1..bc7e1b9 100644
--- a/libs/kstd/include/kstd/units
+++ b/libs/kstd/include/kstd/units
@@ -14,6 +14,11 @@ namespace kstd
   {
     using value_type = ValueType;
 
+    constexpr basic_unit() noexcept
+      : value{}
+    {
+    }
+
     explicit constexpr basic_unit(value_type value) noexcept
         : value{value}
     {}
@@ -142,4 +147,4 @@ namespace kstd
 
 }  // namespace kstd
 
-#endif
\ No newline at end of file
+#endif
diff --git a/libs/multiboot2/include/multiboot2/constants/information_id.hpp b/libs/multiboot2/include/multiboot2/constants/information_id.hpp
index be492eb..27c5300 100644
--- a/libs/multiboot2/include/multiboot2/constants/information_id.hpp
+++ b/libs/multiboot2/include/multiboot2/constants/information_id.hpp
@@ -57,10 +57,10 @@ namespace multiboot2
     smbios_tables,
 
     //! A copy of RSDP as defined per ACPI 1.0 specification.
-    acpi_old_rsdp,
+    acpi_rsdp,
 
-    //! A copy of RSDP as defined per ACPI 2.0 or later specification.
-    acpi_new_rsdp,
+    //! A copy of XSDP as defined per ACPI 2.0 or later specification.
+    acpi_xsdp,
 
     //! The network information specified specified as per DHCP.
     networking_information,
@@ -83,4 +83,4 @@ namespace multiboot2
 
 }  // namespace multiboot2
 
-#endif
\ No newline at end of file
+#endif
diff --git a/libs/multiboot2/include/multiboot2/information.hpp b/libs/multiboot2/include/multiboot2/information.hpp
index d2fac2e..a2ded56 100644
--- a/libs/multiboot2/include/multiboot2/information.hpp
+++ b/libs/multiboot2/include/multiboot2/information.hpp
@@ -11,6 +11,7 @@
 #include <elf/section_header.hpp>
 
 #include <algorithm>
+#include <cstddef>
 #include <cstdint>
 #include <cstdlib>
 #include <optional>
@@ -128,6 +129,26 @@ namespace multiboot2
       return kstd::units::bytes{end_address - start_address};
     }
   };
+  
+  struct acpi_rsdp : vla_tag<data::acpi_rsdp, std::byte, std::span>
+  {
+    using vla_tag::vla_tag;
+
+    [[nodiscard]] auto pointer() const noexcept -> range_type
+    {
+      return {data(), size()};
+    }
+  };
+
+  struct acpi_xsdp : vla_tag<data::acpi_xsdp, std::byte, std::span>
+  {
+    using vla_tag::vla_tag;
+
+    [[nodiscard]] auto pointer() const noexcept -> range_type
+    {
+      return {data(), size()};
+    }
+  };
 
   struct information_view
   {
@@ -245,6 +266,26 @@ namespace multiboot2
              std::views::transform(transform_module);
     }
 
+    [[nodiscard]] auto maybe_acpi_rsdp() const noexcept -> std::optional<acpi_rsdp>
+    {
+      return get<multiboot2::acpi_rsdp>();
+    }
+
+    [[nodiscard]] auto acpi_rsdp() const noexcept -> acpi_rsdp
+    {
+      return maybe_acpi_rsdp().value();
+    }
+
+    [[nodiscard]] auto maybe_acpi_xsdp() const noexcept -> std::optional<acpi_xsdp>
+    {
+      return get<multiboot2::acpi_xsdp>();
+    }
+
+    [[nodiscard]] auto acpi_xsdp() const noexcept -> acpi_xsdp
+    {
+      return maybe_acpi_xsdp().value();
+    }
+
   private:
     template<typename Tag>
     [[nodiscard]] constexpr auto get() const noexcept -> std::optional<Tag>
@@ -264,4 +305,4 @@ namespace multiboot2
 
 }  // namespace multiboot2
 
-#endif
\ No newline at end of file
+#endif
diff --git a/libs/multiboot2/include/multiboot2/information/data.hpp b/libs/multiboot2/include/multiboot2/information/data.hpp
index 3b07d20..315eb39 100644
--- a/libs/multiboot2/include/multiboot2/information/data.hpp
+++ b/libs/multiboot2/include/multiboot2/information/data.hpp
@@ -167,8 +167,18 @@ namespace multiboot2
       std::uint32_t end_address;
     };
 
+    //! A copy of the ACPI RSDP
+    struct acpi_rsdp : tag_data<information_id::acpi_rsdp>
+    {
+    };
+
+    //! A copy of the ACPI XSDP
+    struct acpi_xsdp : tag_data<information_id::acpi_xsdp>
+    {
+    };
+
   }  // namespace data
 
 }  // namespace multiboot2
 
-#endif
\ No newline at end of file
+#endif
-- 
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