x86_64/device_io: switch to typed port io.

2 files changed, 19 insertions, 7 deletions

diff --git a/arch/x86_64/include/x86_64/device_io/port_io.hpp b/arch/x86_64/include/x86_64/device_io/port_io.hpp
index ceabf4a..9f115eb 100644
--- a/arch/x86_64/include/x86_64/device_io/port_io.hpp
+++ b/arch/x86_64/include/x86_64/device_io/port_io.hpp
@@ -2,6 +2,7 @@
 #define TEACHOS_X86_64_IO_PORT_IO_HPP
 
 #include <array>
+#include <concepts>
 #include <cstddef>
 #include <cstdint>
 #include <string_view>
@@ -10,6 +11,16 @@
 namespace teachos::io::x86_64
 {
 
+  //! The requirements imposed on a type usable for port I/O.
+  template<typename ValueType>
+  concept port_io_type = requires {
+    requires sizeof(ValueType) == 1 || sizeof(ValueType) == 2 || sizeof(ValueType) == 4;
+    requires std::default_initializable<ValueType>;
+    std::bit_cast<ValueType>(
+        std::conditional_t<sizeof(ValueType) == 1, std::byte,
+                           std::conditional_t<sizeof(ValueType) == 2, std::uint16_t, std::uint32_t>>{});
+  };
+
   //! An I/O port of a given size at a given address.
   //!
   //! Port I/O leverages a separate address space to communicate with devices via the memory bus, allowing for byte to
@@ -17,13 +28,14 @@ namespace teachos::io::x86_64
   //!
   //! @tparam Address The address (port number) of the I/O port.
   //! @tparam Size The size (in bytes) of the I/O port.
-  template<std::uint16_t Address, std::size_t Size>
-    requires(Size == 1 || Size == 2 || Size == 4)
+  template<std::uint16_t Address, port_io_type ValueType>
   struct port
   {
     //! The type of data available for reading and writing through this port.
-    using value_type =
-        std::conditional_t<Size == 1, std::byte, std::conditional_t<Size == 2, std::uint16_t, std::uint32_t>>;
+    using value_type = ValueType;
+
+    //! The size of the I/O port
+    constexpr auto static size = sizeof(value_type);
 
     //! Read from the I/O port.
     //!
@@ -54,7 +66,7 @@ namespace teachos::io::x86_64
     //!
     //! This index is used to select the correct assembly templates for the given operation (read or write), as well as
     //! the clobbered data register, from the relevant template arrays.
-    constexpr auto static asm_template_index = Size / 2;
+    constexpr auto static asm_template_index = size / 2;
 
     //! The assembly templates used for reading from an I/O port.
     constexpr auto static read_code = std::array{
diff --git a/arch/x86_64/include/x86_64/vga/crtc.hpp b/arch/x86_64/include/x86_64/vga/crtc.hpp
index 8bdc12d..b2c8028 100644
--- a/arch/x86_64/include/x86_64/vga/crtc.hpp
+++ b/arch/x86_64/include/x86_64/vga/crtc.hpp
@@ -10,12 +10,12 @@ namespace teachos::vga::x86_64::crtc
   /**
    * @brief The address port of the CRT Controller.
    */
-  using address = io::x86_64::port<0x3d4, 1>;  // NOLINT(cppcoreguidelines-avoid-magic-numbers)
+  using address = io::x86_64::port<0x3d4, std::byte>;  // NOLINT(cppcoreguidelines-avoid-magic-numbers)
 
   /**
    * @brief The data port of the CRT Controller.
    */
-  using data = io::x86_64::port<0x3d5, 1>;  // NOLINT(cppcoreguidelines-avoid-magic-numbers)
+  using data = io::x86_64::port<0x3d5, std::byte>;  // NOLINT(cppcoreguidelines-avoid-magic-numbers)
 
   namespace registers
   {